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Synthesis and Surface Engineering or Iron Oxide Nanoparticles for Biomedical Applications
Abstract
Superparamagnetic iron oxide nanoparticles (SPION) with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications such as magnetic resonance imaging contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery and in cell separation, etc. All these biomedical and bioengineering applications require that these nanoparticles have high magnetization values and size smaller than 100 nm with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. In addition, these applications need special surface coating of the magnetic particles, which has to be not only non-toxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. To this end, most work in this field has been done in improving the biocompatibility of the materials, but only a few scientific investigations and developments have been carried out in improving the quality of magnetic particles, their size distribution, their shape and surface in addition to characterizing them to get a protocol for the quality control of these particles. Nature of surface coatings and their subsequent geometric arrangement on the nanoparticles determine not only the overall size of the colloid but also play a significant role in biokinetics and biodistribution of nanoparticles in the body. The types of specific coating, or derivatization, for these nanoparticles depend on the end application and should be chosen by keeping a particular application in mind, whether it be aimed at inflammation response or anti-cancer agents. Magnetic nanoparticles can bind to drugs, proteins, enzymes, antibodies, or nucleotides and can be directed to an organ, tissue, or tumour using an external magnetic field or can be heated in alternating magnetic fields for use in hyperthermia. This review discusses the synthetic chemistry, fluid stabilization and surface modification of superparamagnetic iron oxide nanoparticles, as well as their use for above biomedical applications.
... Iron oxide nanoparticles (IO-NPs) with suitable surface chemistry are widely used for several applications such as tissue repair, magnetic resonance imaging contrast enhancement, immunoassay, biological fluid detoxification, drug delivery [1,2], and cell separation [3]. For example, IO-NPs have many advantages in cancer treatment, cancer diagnosis [4,5], cancer hyperthermia therapy [6], and demonstrating safety when enjoyed in clinical use for about nine decades [6]. ...
... For instance, all biomedical and bioengineering applications need IO-NPs to have sizes smaller than 100 nm. Furthermore, the applications of small iron oxide particles in vitro diagnostics have been practiced for approximately 40 years [2]. In the last decade, improved investigations with ...
... It has long been a scientific and technological challenge to produce modified size and shape magnetic nanoparticles. For example, physical methods such as gas-phase deposition and electron beam lithography are elaborate procedures that suffer from the inability to control the size of nanoparticles in the nanometer size range, as demonstrated in the literature [2]. In this paper, highly stable and water-dispersible IO-NPs are produced in the same conditions with narrow size distributions, which were in the range of (4.8-7.5 nm, 6.3-8.72 nm, 10.2-14.2 ...
In this study, stable novel iron oxide nanoparticles (IO-NPs) were synthesized via chemical and green methods. In the chemical method, p-aminobenzoic acid (AB), diacetyl monoxime (DIA), and adenosine 5-monophosphate disodium (AD) were used as stabilized ligands, whereas the extract of Teucrium apollinis was used in the green synthesis method. The effect of these stabilized ligands on the size, stability, and antibacterial activity of IO-NPs was carried out. The synthesized IO-NPs were characterized using UV-Visible absorption spectroscopy (UV-Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), and attenuated Fourier transform infrared (ATR-FTIR). IO-NPs offered spherical shapes with small sizes (5 nm, 6 nm, 8 nm, and 34 nm) for IO-NPs functionalized by DIA, AD, AB, and Teucrium apollinis, respectively. This study shows a relationship between the type of NPs and Pseudomonas aeruginosa growth. The IO-NP functionalized by plant extract has a higher antibacterial effect than IO-NPs chemically synthesized. Because it has more infinity toward bacteria cells than other NP, it has a high ability to penetrate the membrane of bacterial cells. The use of Teucrium apollinis extract could be an eco-friendly way to synthesize IO-NP that offers a novel and potential alternative to chemically synthesized IO-NP.
... An eminent interest in exploring the realm of iron oxides has been nourished by comprehension of their remarkable physical behaviors and their inherent physicochemical properties, most of which have been found appealing for various appli-cations. Until now, iron oxides have been successfully applied in many branches of human activities comprising first media to store information, tools for diagnostic, 1-3 therapeutic, 4,5 and drug-delivery purposes in medicine, [6][7][8][9] agents enhancing photocatalytic/catalytic performances in diverse chemical processes, materials improving efficiency of energy-generating cells (e.g., cells for the direct solar splitting of water and hydrogen generation), 10 key components in spintronic/electronic devices and energy-storing units (e.g., Li-ion batteries), 11,12 sorbents removing toxic inorganic and organic/biological pollutants from the environment, 13,14 among many others. [15][16][17] Such a broad portfolio of iron oxide applications is attributed to their high abundance, low cost, and diversity of chemical procedures to synthesize them with desirable physicochemical features. ...
... Thus, γ-Fe 2 O 3 is described with a stoichiometric formula specified as [(Fe 3+ ) T 22,23 Apart from theoretical studies, nanosized γ-Fe 2 O 3 is the most significant form of ferric oxide, which has previously been used in assorted magnetism-based technologies (e.g., information storage pigments, magnetic fluids, gas sensors, magneto-optical devices, magneto-caloric refrigeration, etc.) and medical appliances (e.g., NMR imaging agent, medical diagnosis, cell labeling, and separation, targeted drug delivery, etc.). [6][7][8]15 Similar to β-Fe 2 O 3 , ε-Fe 2 O 3 is rare, metastable crystalline form of iron(III) oxide; initially observed in 1934 and primarily described in 1963. 22,23,32 It occurs only in the nanoworld with a scarce natural abundance. ...
... Due to its robust magnetic reactivity in the presence of small external magnetic fields and superparamagnetic properties at nanoscale, Fe 3 O 4 has been found to be effective in many biomedical applications such as contrast agents, carriers of drugs, and heating elements in magnetically-assisted hyperthermia for cancer treatment, and catalytical processes such as magnetically-separable catalysts. 6,7,21,37,38 It is widely acknowledged that the physical and chemical features and applicability of nanocrystalline iron oxides can be altered by their size and morphology, surface functionalization, particle arrangement and texture, and cation substitution. [6][7][8]10,13,[15][16][17] In this review, the selected and vitally important applications of iron oxide nanomaterials are deliberated in the domain of catalysis and environmental remediation (see Fig. 3). ...
Iron oxide nanoparticles have been intensively investigated owing to their huge potential as diagnostical, therapeutical, and drug-carrier agents in biomedicine, sorbents in environmental technologies, sensors of various inorganic and organic/biological...
... This discrepancy can be attributed to the hydration layer formed on the IO@Si MNPs' surface, stemming from robust intermolecular interactions within the Si-O bonds present in the aqueous solution 58 . These small hydrodynamic sizes are promising to circumvent the reticuloendothelial system, causing more maintenance in the blood circulatory system, and potentially passing through the BBB around the brain tumor region 60 . Coating the second layer of the shell increased the IO@Si@Gel MNPs and PHT-loaded IO@Si@Gel MNPs sizes to 89 nm and 81 nm, respectively. ...
... Hence, it is crucial to apply an appropriate surface coating to ensure the stability of these NPs. In this study, oleic acid was utilized during the preparation process to passivate the surface of the NPs, forming a protective monolayer that enhances stability 60,61 . Following the silica layer deposition onto the surface of the IO MNPs, the IO@Si MNPs' surface charge was elevated to − 34 mV, primarily attributable to the negative charge owing to the hydroxyl groups present in the silica. ...
The current study developed an innovative design for the production of smart multifunctional core-double shell superparamagnetic nanoparticles (NPs) with a focus on the development of a pH-responsive drug delivery system tailored for the controlled release of Phenytoin, accompanied by real-time monitoring capabilities. In this regard, the ultra-small superparamagnetic iron oxide@silica NPs (IO@Si MNPs) were synthesized and then coated with a layer of gelatin containing Phenytoin as an antiepileptic drug. The precise saturation magnetization value for the resultant NPs was established at 26 emu g⁻¹. The polymeric shell showed a pH-sensitive behavior with the capacity to regulate the release of encapsulated drug under neutral pH conditions, simultaneously, releasing more amount of the drug in a simulated tumorous-epileptic acidic condition. The NPs showed an average size of 41.04 nm, which is in the desired size range facilitating entry through the blood–brain barrier. The values of drug loading and encapsulation efficiency were determined to be 2.01 and 10.05%, respectively. Moreover, kinetic studies revealed a Fickian diffusion process of Phenytoin release, and diffusional exponent values based on the Korsmeyer-Peppas equation were achieved at pH 7.4 and pH 6.3. The synthesized NPs did not show any cytotoxicity. Consequently, this new design offers a faster release of PHT at the site of a tumor in response to a change in pH, which is essential to prevent epileptic attacks.
... These hybrid nanoparticles have potential use as noval intravascular probes for diagnostic (imaging) purpose. 4 Magnetic nanoparticles can be administered intravenously or orally and transported through blood stream to the desired area of treatment. Super paramagnetic particles do not retain any magnetism after removal of magnetic field and they are physiologically well tolerated in vivo. ...
... Monitoring and Sensing Capabilities: Nanomaterials can be integrated into biosensors or nanosensors to monitor microbial activity and contaminant levels in real-time. For instance, quantum dots have been used as fluorescent probes to detect the presence of specific microorganisms or track the biodegradation process [60]. These monitoring tools enable the optimization of bioremediation strategies and provide valuable insights into the remediation progress. ...
This book series invites all the Specialists, Professors, Doctors, Scientists, Academicians, Healthcare professionals, Nurses, Students, Researchers, Business Delegates, and Industrialists across the globe to publish their insights and convey recent developments in the field of Nursing, Pharmaceutical Research and Innovations in Pharma Industry. Book series on Pharmacy and Nursing covers research work in a set of clinical sciences and medicine.
... Advances in nanotechnology now make it possible to precisely engineer the essential properties of these tiny particles, just like other nanomaterial-based systems. It is possible to modify the composition, size, shape, and surface chemistry of NPs to influence their in vivo behaviour, as well as their magnetic properties [130,131]. A biomedical MNP platform in its most basic form has a code made up of inorganic NPs, and a surface layer that is biocompatible, providing stability in physiological conditions. ...
Atherosclerosis continues to be a leading cause of morbidity and mortality globally. The precise evaluation of the extent of an atherosclerotic plaque is essential for forecasting its likelihood of causing health concerns and tracking treatment outcomes. When compared to conventional methods used, nanoparticles offer clear benefits and excellent development opportunities for the detection and characterisation of susceptible atherosclerotic plaques. In this review, we analyse the recent advancements of nanoparticles as theranostics in the management of atherosclerosis, with an emphasis on applications in drug delivery. Furthermore, the main issues that must be resolved in order to advance clinical utility and future developments of NP research are discussed. It is anticipated that medical NPs will develop into complex and advanced next-generation nanobotics that can carry out a variety of functions in the bloodstream.
... In the biomedical fields, silica and iron oxide are the most common nanomaterials for drug delivery, tissue engineering, and cell promotion [30]. After entering cells, the NPs would degrade into irons and induce reactive oxygen species (ROS) through the changing of mitochondrial related organelles' structures [31]. The surplus production of ROS could create a chain reaction inside, along with the autophagy process of the cell, which would consist of a process of discarding superfluous and unnecessary materials from cells and regulating the ROS homeostasis [32]. ...
Rapid advancements in nanotechnology have expanded its applications and synergistic impact on modern nanosystems. The comprehensive assessment of nanomaterials’ safety for human exposure has become crucial and heightened. In addition to the characterization of cell proliferation and apoptosis, probing the implication of autophagy is vital for understanding the ramification of nanomaterials. Hence, HEK-293 kidney cells were employed to understand the changes in induction and perturbation of autophagy in cells by iron oxide (Fe3O4) and silica (SiO2) nanoparticles. Interestingly, Fe3O4 worked as a potent modulator of the autophagy process through its catalytic performance, which can develop better than that of SiO2 nanoparticles mechanism, stressing their therapeutic implication in the understanding of cell behaviors. The quantification of reactive oxygen species (ROS) was measured along with the process of autophagy during cell growth. This modulated autophagy will help in cell fate determination in complementary therapy for disease treatment, provide a clinical strategy for future study.
... These magnetic NPs can disperse in appropriate solvents and create homogeneous suspensions known as ferrofluids by using suitable surface coating. Such suspension is able to interact with the external magnetic field and be positioned to a precise area, enabling AC magnetic field-supported carcinoma treatment and magnetic resonance imaging for medicinal diagnostics [43][44][45]. Maghemite is a byproduct of the weathering of the magnetite or the heating of other oxides of iron that occurs in soils. It shapes continuous solid solvent with magnetite and is metastable in relation to hematite [46]. ...
With recent advances in nanotechnology, various nanomaterials have been used in various fields. The unique physiochemical properties and biocompatibility of Iron oxide nanoparticles (IONs) allow the exploration of IONs in various applications, including biomedicine, electronics, water/wastewater treatment, and sensors. The charge of IONs, crystallization, zeta potential solution stability, the coating, and synthetic methods are essential parameters that influence their applications in various fields. Each of these factors affects the optical and physical characteristics of the created material as well as determines the field of its application. In this regard, the main challenge of technology is related to the control of its physical properties. Therefore, the synthesis process used determines the properties of the synthesized substance. Pulsed laser ablation in liquid (PLAIL) is regarded as a green and environmentally friendly method for creating metal and metal oxide nanoparticles, and it does not require the use of toxic chemicals. The physical mechanism of laser ablation in a liquid environment, the subsequent growth of nanostructures, the essential laser technological parameters that determine the nanostructures’ properties, and the liquid medium’s influence are discussed. The size, shape, and distribution are crucial factors that influence the pharmacokinetics and bio-distribution of IONPs. Physiochemical properties such as size, shape, and surface and magnetic properties, as well as agglomeration of IONs and methods to enhance their stability, are also discussed. This review focuses on the recent development and various strategies in structure and magnetic properties of iron oxide nanoparticles (NPs) as well as the preparation processes of iron oxide NPs via pulsed laser ablation, and their environmental and medical applications.
... [40] Like the MNPs we used, MNPs whose sizes range between 10 and 200 nm are preferred to avoid removal by renal extravasation (<10 nm) or capture by the spleen (>200 nm). [41] In addition, our spatially localized delivery approach could help to reduce the required amounts of MNPs and AAVs to minimize potential toxicity effects, immune response/inflammation, and cost of goods. ...
Adeno‐associated viruses (AAVs) are intensively explored for gene therapies in general and have found promising applications for treating retina diseases. However, controlling the specificity (tropism) and delivery of AAVs to selected layers, cell types, and areas of the retina is a major challenge to further develop retinal gene therapies. Magnetic nanoparticles (MNPs) provide effective delivery platforms to magnetically guide therapeutics to target cells. Yet, how MNPs can deliver AAVs to transfect particular retina layers and cells remains elusive. Here, it is demonstrated that MNPs can be used to transport different AAVs through the retina and to modulate the selective transduction of specific retinal layers or photoreceptor cells in ex vivo porcine explants and whole eyes. Thereby, transduction is triggered by bringing the viruses in close proximity to the target cell layer and by controlling their interaction time. It is shown that this magnetically guided approach to transport AAVs to selected areas and layers of the retina does not require the cell‐specific optimization of the AAV tropism. It is anticipated that the new approach to control the delivery of AAVs and to selectively transduce cellular systems can be applied to many other tissues or organs to selectively deliver genes of interest.
... Metal oxide NPs possess many chemical and physical features, including particle size, density, and surface area [20]. Metal oxide nanoparticles have been synthesized, including nickel oxide [21], zinc oxide [22], and iron oxides [23]. Iron oxide nanoparticles are particularly intriguing in comparison to other nanomaterials due to their notable features, including a high surface area to volume ratio, rapid kinetics, robust adsorption capacities [24], and exceptional magnetic properties [25]. ...
This study examines the degradation of malachite green by utilizing Fe3O4 nanoparticles. These nanoparticles were prepared using an extract derived from Cannabis sativa roots. The synthesized catalysts were characterized using X-ray diffraction, scanning electron microscopy, UV-visible spectroscopy, and vibrating sample magnetometry to assess their structural, optical, and magnetic properties. The results suggest that the CF2 nanoparticles demonstrate exceptional degrading efficiencies of 87.72% when exposed to UV-visible light. Furthermore, the mildly alkaline conditions were determined to be advantageous for enhancing the efficiency of catalyst degradation (97.55%), as evidenced by the pH variation experiment. The study also included an examination of the main active species and possible photocatalytic mechanism. Furthermore, there was a minimal decrease of just 20.95% in the efficiency of degradation after four rounds of the degradation reusability experiment. Therefore, the Fe3O4 nanoparticles manufactured using Cannabis sativa roots show potential for use as very effective photocatalysts in the degradation of malachite green. Furthermore, anti-bacterial efficacy was checked against the bacterial strains Escherichia coli, Salmonella typhi, Shigella sonnei, Pseudomonas aeruginosa, and Staphylococcus aureus. This work presents a simple green method for producing innovative Fe3O4 nanoparticles as a remarkable nanomaterial for water bodies to degrade hazardous pollutants by visible light photodegradation and as an antibacterial agent.
... Furthermore, these particles exhibit magnetic characteristics, and there are also nanoparticles composed of different metals like nickel, cobalt, and their chemical compounds possess same features. Recent research has extensively studied magnetic nanoparticles due to their remarkable properties, which hold potential applications in various fields such as stimulation [30], biopharmaceuticals [31], magnetic resonance imaging [32], magnetic particle imaging [3], data storage, and environmental remediation [34]. ...
Our ongoing research involves the synthesis of iron nanoparticles through a multi-step procedure that includes intricate processes resulting in the disruption of the bonds between the fundamental components of the oyster shell. As a result, we successfully extract iron nanoparticles from oyster shell powder. The obtained iron nanoparticles were characterized using X-ray Diffraction Analysis (XRD), Scanning Electron Microscopy (SEM), and FTIR-Based Analysis. These techniques confirmed that the nanoparticles possess the standard properties and meet the optimal specifications necessary for their function as an antibiotic to suppress bacterial action. Objective: Our research aims to biologically generate iron nanoparticles from oyster shells, meeting conventional standards that enable them to function as antibiotics. Methods: Our research employs a method for producing iron nanoparticles that involves a series of processes combined with the addition of chemicals that disrupt the bonds between the fundamental constituents of the oyster shell. This shell is first purified and then ground into a powder. Results And Characterization: The results were obtained using the SPSS statistical program, and the size of the iron particles was determined using the XRD crystallite (grain) calculator, specifically the Scherrer Equation. The characteristics acquired from the steps involving Fe NPs in our ongoing study are confirmed based on the measurements conducted using X-ray Diffraction Analysis (XRD), Scanning Electron Microscopy (SEM), and FTIR-Based Analysis. These measurements indicate that the particles have a satisfactory size range of 30-100 nanometers.Conclusion: We conclude from our current study that there are no significant differences between the number of patients and the three stages type that recorded through this periodic time, even if there is a difference in age and gender.
... Hence, the non-specificity associated with conventional chemotherapy can be overcome by complexing them with magnetic NPs. 122 For the drug targeting, these nanocarriers should be biocompatible, hydrophilic and non-toxic. As mentioned earlier in this review; the diameter, shape, surface charge, surface modifications and composition of the magnetic nanoparticles have influence on magnetic property and drug delivery. ...
Numerous therapeutic measures have been developed in oncology to combat various types of cancer, which is a leading cause of death worldwide. These therapies range from conventional approaches to high-end precision medicines, all aimed at ensuring therapeutic efficacy and the patient's survival. However, drug resistance and off-target side effects continue to hinder treatment efficacy. In the case of solid tumors that have hypoxic regions that cause treatment resistance and a high risk of tumor recurrence. To address this, advanced therapies have been designed or under pipeline to specifically target cancer cells by considering their unique features. This review article primarily focuses on different treatment methods developed using the peculiar properties of the tumor microenvironment.
... It is also used as a pigment and a polishing agent. It exhibits antiferromagnetic ordering below the Néel temperature, which is around 120 K (Gupta, et al., 2005). However, FeO displays additional complexity in its magnetic properties. ...
This review focuses on the physical properties of three magnetic materials: Cobalt oxide (Co3O4), Iron oxide (FeO), and Manganese oxide (MnO). These materials exhibit interesting magnetic behavior and have been extensively studied due to their potential applications in various fields, including spintronics, magnetic storage, and magnetic sensors. In this review, we provide a comprehensive overview of the physical properties of Co3O4, FeO, and MnO, including their crystal structures, magnetic properties, structural properties, electrical properties, and thermal Properties. We also discuss the factors influencing the magnetic properties of these materials, such as temperature, doping, and external magnetic fields. Additionally, we highlight the technological applications and challenges associated with these magnetic materials. This review serves as a valuable resource for researchers and scientists interested in understanding and utilizing the physical properties of Co3O4, FeO, and MnO.
... The reason is the large number of potential biomedical applications that these particles may have in diagnostics and therapy. One can mention contrast enhancement in magnetic resonance imaging [1], magnetic hyperthermia treatment [2], detoxification of biological fluids [3], magnetic separation of cancer cells [4] or alternating magnetic field-induced thermal strengthening of the shells of microcapsules and liquid marbles [5]. ...
The investigation and clarification of the properties of surface-functionalized superparamagnetic nanoparticles in a biological environment are key challenges prior to their medical applications.
In the present work, electron paramagnetic resonance spectroscopy (EPR) combined with the spin labeling technique was utilized to better understand the behavior of nitroxides attached to magnetite nanoparticles dispersed in body fluid. EPR spectra of spin-labeled, silane-coated Fe3O4 nanoparticles in human serum and whole blood were recorded and analyzed for both room- and low-temperature values. In all cases, the obtained EPR signal consisted of a broad line from magnetite cores and a characteristic signal from the attached 4-Amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4-amino-TEMPO). Even for liquid samples, the anisotropic components of magnetic tensors did not fully average out, which was reflected in the differences in the intensity of three narrow hyperfine lines from nitroxide. At 230 K the irregular slow-motion signal from the attached radical was also simulated using the EasySpin toolbox, which allowed to determine the parameters related to magnetic tensors and the dynamics of the spin label. The study showed that the anisotropy of the motion of the spin label 4-amino-TEMPO reflects its interactions with the surrounding medium and the manner of the
attachment of the nitroxide to the surface of nanoparticles.
... In the whole organism, the toxic effects of iron oxides NPs are related to their pharmaco/toxicokinetics [64], in which size plays a major role. It is known, that magnetite NPs smaller than 10 nm are quickly eliminated by the kidneys, while particles larger than 200 nm are captured by the organs of the reticuloendothelial system, especially spleen [65]. ...
Among nanoparticles (NPs) of metal oxides, magnetite NPs are the most well-known. The need for regulations related to the safety of magnetite NPs requires a deep understanding of their toxicological paradigm. The purpose of the presented review is to analyze the methods of studying the magnetite NPs toxicity and to summarize their toxicity factors based on the literature data. Literature sources were searched in the PubMed database, and 99 works were selected, supplemented with articles from other databases in some cases. It is shown that the study of the magnetite NPs toxicity became widespread during the last decade, reflecting the expansion of the list of synthesized magnetic NPs and the awareness that the prospects for their use depend on the safety of the created nanomaterial. The safety assessment of magnetite NPs on cell lines is the most popular. Primitive and more highly organized animals can be used to evaluate various aspects of the magnetite NPs toxicity. The toxicity factors of magnetite NPs depend on their characteristics (core composition, coating, size, and shape) and the mode of application (concentration, dose, exposure, type of cells, or animal model). One of the main mechanisms of nanomagnetite toxicity is the interference with iron metabolism and increased generation of reactive oxygen species leading to the disruption of cell proliferation, viability, and metabolism. Thus, the toxicity of magnetite NPs is studied by various methods and at different levels of living systems. Understanding the mechanisms of nanotoxicity should contribute to the targeted design of safe magnetic NPs.
... Ferromagnetic nanoclusters are also of great scientific and technical importance. They can be used in different systems for magnetic cooling, mixing, identification, and acceleration of reactions of substances [21,22], as well as for biomedical purposes [23][24][25], due to the high biocompatibility of the magnetic field and its ability to penetrate deep into living tissues without damaging them. However, their use is limited due to oxidation in air. ...
Columnar phases consisting of a group of carbon toroidal molecules (C120, C192, C252, C288) are studied numerically. Each nanotorus was previously doped with an iron atom. This made it possible to use an external magnetic field as a tool for influencing both an individual molecule and a linear fragment of the columnar phase. A high-precision scheme for calculating the dynamics of large molecules with a rigid frame structure is proposed to solve the problem. The group dynamics of nanotori clusters under the influence of an external magnetic field has been studied using classical molecular dynamics methods. The influence of the molecular cluster size, temperature, magnetic moment of the molecule, and magnetic field direction on the collective behavior of iron-doped toroidal molecules with different contents of carbon atoms is analyzed. Molecular dynamics calculations showed that systems of nanotori doped with a single iron atom retain a columnar structure both in the absence and in the presence of an external magnetic field. The columnar fragment behaves as a stable linear association of molecules even at sufficiently high values of magnetic induction, performing a coordinated collective orbital rotation around a common center of mass on a nanosecond time scale.
... The superparamagnetic behavior of biocompatible nanoparticles is another crucial prerequisite. Magnetic materials have been investigated in several application domains over the last few decades [1][2][3][4]. Different kinds of magnetic materials, such as Fe-based nanoparticles, exhibit intriguing behaviors depending on the synthesis techniques [5][6][7][8]. Because they have a wide range of uses, particularly in rechargeable lithium batteries, alkaline metal ferrites with the general formula AFeO 2 (where A = Li, Na, and K) have been thoroughly researched [9][10][11]. ...
The current study reports on the shape, size distribution, structure, magnetic properties, and biocompatibility of potassium ferrite nanoparticles (KFeO2 NPs), which were produced using the traditional sol–gel method. The development of spherical nanoparticles with an orthorhombic structure has been verified using X-ray diffraction and Field emission scanning electron microscopy. According to transmission electron microscopy, the particles have a size of about 30 nm. The production of metal (Fe, K) bonds was demonstrated by thermogravimetric analysis and Fourier transform-infrared spectroscopy. The optical analysis shows that the KFeO2 nanoparticles' bandgap is 1.88 eV, which is within the visible spectrum. Further Photoluminescent properties were investigated and showed strong luminescence in 600 nm range thus confirming oxygen deficient property. The synthesized KFeO2 NPs exhibited superparamagnetic behavior, with a saturation magnetization of 22.12 emu/g, according to the vibrating sample magnetometer examination. Furthermore, as determined by MTT and BrdU assays, the observed in vitro cytotoxicity and lymphoproliferative effects appeared to be biocompatible and concentration-dependent. The MTT assay was used in an in vitro cytotoxicity test which demonstrated the biocompatibility of KFeO2 NPs at 100 mg/mL of particle concentration. The findings of the current study suggest that potassium ferrite magnetic nanomaterials, which have better optical qualities and less coercivity in optoelectronic instruments, could be used in transformer cores. They can also be used as iron-oxide-based nanomaterials for applications in the health and medical science sectors.
... These tailored particle properties offer an added functional value in many industrial sectors, resulting in a wide range of potential applications such as battery electrodes (Meierhofer et al., 2017), gas sensors (Kemmler, Pokhrel, Mädler, Weimar, & Barsan, 2013;Mädler et al., 2006), catalysts (Pokhrel & Mädler, 2020;Strobel, Baiker, & Pratsinis, 2006), biomedical devices (Gupta and Gupta, 2005a;Sotiriou, 2013) and environmental safety (Khan, Saeed, & Khan, 2019;Meierhofer & Fritsching, 2021). The performance and industrial suitability of these final products are directly influenced by the quality of the synthesized nanoparticles, which differ depending on the mass transfer of the precursor into the gas phase via either droplet-to-particle or gas-to-particle synthesis route Stark, Mädler, Maciejewski, Pratsinis, & Baiker, 2003;Strobel & Pratsinis, 2007, 2011. ...
Puffing (weak disruptions) and µ-explosions (strong disruptions) play an important role in the synthesis of nanoparticles via flame spray pyrolysis (FSP), as they increase the mass transport of the liquid precursor-solvent system into the gas phase, thus contributing to the formation of homogeneous nanoparticles. Therefore, the targeted experimental study of droplet breakup using single droplet experiments is an essential step in gaining fundamental knowledge about time- and concentration-dependent mechanisms of these disruptions. Here, we study the disruptive combustion of single droplets containing a commonly applied Tin-based precursor with initial Sn molar concentrations ranging from 0.05 mol L-1 to 1 mol L-1. High-speed imaging techniques have been combined with high sample-rate acoustic measurements to detect, distinguish, and quantify droplet disruption phenomena. It has been demonstrated that precursor concentrations up to 0.25 mol L-1 are more prone to µ-explosions, whereas higher Sn molar concentrations show puffing. This shift in the disruption modes between different precursor concentrations is characterized by a boundary that is acoustically identified by quantifying the strength of a disruption using a disruption strength index. Droplet sizes at the instant of the breakup are suggested to play a central role in causing the different droplet breakup characteristics. While the initial droplet sizes of the different precursor solutions are almost identical, they vary at the instant of disruption, resulting in distinct breakup characteristics. Thus, puffing is detected at the instant of disruption for droplet sizes above 55 µm, whereas
µ-explosions occur for smaller droplets. Using high-speed measurements to investigate a fixed precursor concentration with two different initial droplet sizes confirms instantaneous droplet-size-dependent effects on the disruption mode.
... Owing to their size, which ranges from approximately 1 to 100 nm, nanoparticles exhibit specific and controllable properties that distinguish them from their macroscopic counterparts, thus paving the way for unique applications [1] [2] [3]. The alteration in properties is attributed to two primary effects: surface effects or size reduction effects, where a decrease in particle size increases the proportion of atoms on the surface; and quantum modification effects, which alter the electronic structure [1] [4]. The ratio of surface atoms to bulk atoms escalates significantly as particle size diminishes. ...
... EGFR (also referred to as ErbB1 and HER, 1), ErbB3 (HER 3), HER-2, and ErbB4 (HER4) are the members of the EGFR family. Among these, breast cancer had overexpressed HER-2 [115,116]. Numerous clinical trials examining VEGF, EGFR, Src and mTOR molecular markers, aimed at the treatments of triple-negative breast cancer are ongoing. ...
One common cancer among women is breast cancer. Chemotherapy, radiation therapy, and surgery have historically been used as breast cancer treatments. Thanks to recent technological advancements , we have been able to progressively comprehend the complexity and heterogeneity of diseases, which has led to the development of more effective treatments for many conditions. Working with variably shaped nanoparticles, nanotechnology has recently enabled us to work on tumor targeting and drug delivery, and it has undoubtedly helped to reduce the spread and death of breast cancer. The efficacy of treatment for breast cancer can be increased by a variety of target therapies made possible by nanotechnology. The current review discusses the advantages and disadvantages of nanotechnology-based therapy for breast cancer while also highlighting the disease's current state. The article will provide an overview of the current strategy available for better treatment of breast cancer and aid in understanding the various drug delivery systems designed to provide effective treatment for the disease. By utilizing cutting-edge technologies and early screening, breast cancer fatalities can be decreased. Drug delivery methods based on nano carriers enable medication to reach the target site at the ideal concentration with the least amount of harmful side effects.
... This technique is widely used in scientific research and industrial production. [1][2][3][4][5][6] The principle of DLS for particle size measurement is to use the measured scattered light signal from randomly fluctuating particles to calculate the intensity autocorrelation function (ACF) in real time. Then the Siegert relation is used to obtain the electric field ACF, and the PSD is obtained by inverting the electric field ACF. ...
Tikhonov regularization, or truncated singular value decomposition (TSVD), is usually used for dynamic light scattering (DLS) inversion of particles in suspension. The Tikhonov regularization method uses a regularization matrix to modify all singular values in the kernel matrix. The modification of large singular values cannot effectively reduce the variance of the estimated values but may introduce bias in the solution, resulting in poor disturbance resistance in the inversion results. The TSVD method, on the other hand, truncates all small singular values, which leads to the loss of particle size information during the inversion process. The shortcomings of the two methods mentioned above do not have a significant impact on the inversion of high signal-to-noise ratio data. However, compared to the classical DLS particle size inversion for non-flowing suspended particles, the DLS inversion of flowing aerosols is more significantly affected by noise, and the extraction of particle size information is more difficult due to the effect of flow velocity, resulting in worse inversion results with increasing aerosol flow velocity for both methods. To improve the accuracy of the particle size distribution (PSD) of flowing aerosols, we introduced a kernel matrix into the regularization matrix, and based on the principles of the two methods, the spectral information of the kernel matrix was utilized to make the modification of small singular values by the regularization matrix. Correspondingly, weak or no modification was made according to the values of large singular values to reduce the introduction of bias. The inversion results of simulated and measured data indicate that the reconstruction of the regularization matrix improves the anti-disturbance performance and avoids the loss of particle size information during the regularization inversion process, thereby significantly improving the PSD accuracy, which is affected by the dual effects of flow velocity and noise in the DLS measurement of flowing particles. The peak error and distribution error of the inversion results by reconstructing the regularization matrix are lower than those of Tikhonov regularization.
... Nitrogen gas through the solution not only can prevent the oxidation but also reduces the particle size. The solution is then stirred and purged with N 2 gas until the temperature reached 373°F under a nonoxidizing, oxygen-free environment 50 The product was collected by an external magnetic field and rinsed with deionized water three times, and dried in a vacuum at 80°C for an hour to obtain MNPs. 51 ...
Montmorillonite clay and agar are naturally occurring materials of significant importance in designing biocompatible materials tailored for applications in biotechnology and medicine. The introduction of magnetic properties has the potential to significantly boost their characteristics and expand their applications. In this study, we have successfully synthesized highly intercalated magnetic composites, incorporating magnetic iron oxide nano-particles (MNPs), montmorillonite clay (MMT), and agar (AG), through a thermo-physicomechanical method. Three samples of MMT-AG with 2, 1.5, and 0.5% MNPs and three sample composites of MNPs-AG with 2, 1, and 0.5% MMT clay are prepared. The synthesized composites were characterized by SEM, XRD, TGA, DTA, and FTIR. SEM analysis revealed a uniform dispersion of MNPs and MMT in the composite. The XRD pattern confirmed the presence of MNPs in the composite site. The TGA and DTA results demonstrated improved thermal stability due to the MNP incorporation. FTIR spectra showed all of the constituents of agar, MNPs, and MMT clay. The swelling ratio was observed to range from 835% to 1739%. The swelling study indicated an increased hydrophobicity with the addition of MNPs to the composite. Antibacterial activities revealed a significant inhibition of Escherichia coli (E. coli) growth by ranging from 10 to 19 nm in the composite. The composite also exhibited a considerable antioxidant action, with IC50 values of 7.96, 46.55, and 57.58 μg/mL, and electrical properties just like conductors.
Herein, we demonstrate the preparation of magnetic polyamide 11 feedstock powders for powder bed fusion (PBF) using liquid-liquid phase separation and crystallization. By adding magnetic nanomaterials during the precipitation process, the particulate additive is incorporated into the polymer matrix. This enables the production of filled systems at single particle level, which is advantageous in terms of the adjustable magnetic strength and homogeneity of the powder. Thermogravimetric analysis is used to determine the additive content and onset temperature of decomposition of composite powders, where additive-enhancement of PA11 powders with magnetic iron oxide nanoparticles showed a positive influence on the thermal stability of the feedstock. Successive analysis of particle size distribution, shape, colour, crystal structure, magnetic properties and thermal properties of the composite powders are carried out and their properties are discussed with respect to the PBF process. A decrease in particle size, width of the thermal process window and isothermal crystallization time can be attributed to the nucleating effect of the magnetic additive. The PBF processability of the composite feedstock is demonstrated by the production of magnetic tensile bar specimens from additive-enhanced PA11 powders with 1 wt. % magnetic iron oxide.
Introduction: To achieve a proper disinfection of the root canal system, besides many irrigant solutions, laser has become increasingly popular in recent years. Bacteria that penetrate deep in the dentine can be destroyed by laser up to 1150 µm. The aim of the study is to investigate and to compare the efficiency of conventional chemical disinfection using cleaning solutions - sodium hypochlorite (2%), citric acid (20%) - and the physical disinfection using a diode laser (940 nm, 1 W) in vitro using extracted teeth. Material and Methods: 23 intact, single rooted teeth were prepared and inoculated with Enterococcus Faecalis. Afterwards samples were taken from each group and placed on solid mediums. The following were applied to members of each group prior to sampling: 2% sodium hypochlorite, 20% citric acid and diode laser (940 nm, 1W). To evaluate the results, so that the bacterial strains on the medium could be counted, quenches were performed from 1/10 and 1/100 dilutions. Statistical analysis was performed using Kruskall-Wallis and unpaired T-test with a value of p>0.05. Results: Statistical analysis on the 3 groups (NaOCl, citric acid, and diode laser) showed significant differences between the counted remaining colonies after disinfection. Conclusions: The diode laser used for disinfection under the used settings is not effective enough, but as an adjuvant, associated with conventional irrigation effective disinfection can be obtained. Keywords: root canal, E. Faecalis, sodium hypochlorite, citric acid, diode laser
This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses.
Thermal decomposition of iron oleate is a simple and widespread method for synthesizing monodispersed iron oxide nanoparticles (IONPs) with well‐defined morphology. However, the complexity of the underlying mechanism makes this method rather sensitive to variations in experimental conditions, and the lack of simple techniques to monitor the reaction progress in situ usually results in poor reproducibility and time‐consuming optimizations. Here, a simple, robust, and versatile in situ marker to monitor particle formation based on a sudden change in the temperature during reflux is reported. A linear relationship between the onset of particle formation and the concentration of surfactants is unveiled, corroborating a ‘chemically activated’ burst nucleation mechanism. Using this linear relationship as a guide, highly uniform spherical, cubic, and star‐shaped particles between 12 and 30 nm can be obtained. This temperature marker and the derived linear relationship not only deepen the understanding of the reaction process, but also provide a powerful tool for the straightforward optimization of IONPs.
Magnetic nanoparticles (MNPs) are appealing materials as assistant to resolve environmental pollution issues and as recyclable catalysts for the oxidative degradation of resistant contaminants. Moreover, they can significantly influence the advancement of medical applications for imaging, diagnostics, medication administration, and biosensing. On the other hand, due to unique features, excellent biocompatibility, high curie temperatures and low cytotoxicity of the Iron-based nanoparticles, they have received increasing attention in recent years. Using an external magnetic field, in which the ferrite magnetic nanoparticles (FMNPs) in the reaction mixtures can be easily removed, make them more efficient approach than the conventional method for separating the catalyst particles by centrifugation or filtration. Ferrite magnetic nanoparticles (FMNPs) provide various advantages in food processing, environmental issues, pharmaceutical industry, sample preparation, wastewater management, water purification, illness therapy, identification of disease, tissue engineering, and biosensor creation for healthcare monitoring. Modification of FMNPs with the proper functional groups and surface modification techniques play a significant role in boosting their capability. Due to flexibility of FMNPs in functionalization and synthesis, it is possible to make customized FMNPs that can be utilized in variety of applications. This review focuses on synthesis, modifications, and applications of Iron-based nanoparticles.
Metal oxide nanostructures have received an increasing attention owing to their unique chemical and physical properties along with their widespread applications in various fields. This article provides an overview of the recent discovery – christened Hydroxides‐Derived Nanostructures, or HDNs – in which hydroxide aqueous solutions (mostly tetramethylammonium hydroxide, TMAH) are reacted at temperatures < 100 °C and under atmospheric pressure with various metal‐containing precursors to scalably prepare novel metal oxide nanostructures. In one case, a dozen commercial and earth abundant Ti‐containing powders such as binary carbides, nitrides, borides, among others, are converted into new, 1D TiO2‐based lepidocrocite (1DL) nanofilaments (NFs). Application‐wise, the 1DLs show outstanding performance in a number of energy, environmental, and biomedical fields such as photo‐ and electrocatalysis, water splitting, lithium–sulfur and lithium‐ion batteries, water purification, dye degradation, cancer therapy, and polymer composites. In addition to 1DL, the HDNs family encompasses other metal oxides nanostructures including magnetic Fe3O4 nanoparticles and MnO2 birnessite‐based crystalline 2D flakes. The latter showed promise in electrochemical energy conversion and storage applications. The developed recipe provides a new vista in the molecular self‐assembly synthesis of nanomaterials that can advance the field with a library of novel nanostructures with substantial implications in a multitude of fields.
The study of nanoparticles has emerged as a prominent research field, offering a wide range of applications across various disciplines. With their unique physical and chemical properties within the size range of 1-100 nm, nanoparticles have garnered significant attention. Among them, magnetic nanoparticles (MNPs) exemplify promising super-magnetic characteristics, especially in the 10-20 nm size range, making them ideal for swift responses to applied magnetic fields. In this comprehensive review, we focus on MNPs suitable for analytical purposes. We investigate and classify them based on their analytical applications, synthesis routes, and overall utility, providing a detailed literature summary. By exploring a diverse range of MNPs, this review offers valuable insights into their potential application in various analytical scenarios.
Aim
The aim of this study is to explore and evaluate the possibility of rambutan-shaped micro-nanostructured γ-Al2O3 material’s usage as an adsorbent in industrial wastewater processing.
Background
Every year, more than 7 million tons of dyestuff-containing wastewater are produced in the industry. Although there are many adsorbents like fly ash and clays, the shortages limit their actual applications. It is still necessary to find a new cheaper adsorbent.
Objective
The paper aimed to investigate the adsorption capacity and decolorization ability of rambutan- shaped γ-Al2O3 material synthesized via a composite soft template method.
Methods
The rambutan-shaped γ-Al2O3 material was prepared and characterized via XRD, TEM, FE-SEM, and FT-IR (See our group’s published article in “Ming Shen*, et al., Acta Phys.-Chim. Sin. 2013, 29 (10), 2286-2294”). The methyl orange aqueous solution was selected as the model of industrial wastewater. The methyl orange solution (15.0 mg·L-1) with different pH (2~9) was exposed to a series of amounts of γ-Al2O3 powder ranging from 10.0 to 70.0 mg. Different concentrations of methyl orange solution, ranging from 5.0 to 200.0 mg·L-1 were also tested with the same amount of γ-Al2O3 powder (50.0 mg). The adsorption-calcination cycle analysis was performed with methyl orange solution (50.0 mg·L-1) and 500.0 mg of γ-Al2O3 powder at pH=3.
Results
The γ-Al2O3 material exhibits excellent adsorption capacity (114.10 mg·g-1) towards acidic methyl orange aqueous solution. At the same time, the decolorization rate of the γ-Al2O3 material reaches about 88%. This material still keeps a 50% decolorization rate after 6 repeats of the adsorption- calcination cycle. Moreover, the excellent self-sedimentation ability of this material also provides an easy separation for future industrial applications.
Conclusion
The γ-Al2O3 material with rambutan-like micro-nanostructure presents excellent adsorption capacity/decolorization ability and self-sedimentation ability. It can be used as a new type of adsorbent for wastewater processing. The rambutan-shaped micro-nanostructure plays an important role in maintaining the adsorption ability of the γ-Al2O3 material.
The present study reports the autoxidation of adrenaline to adrenochrome using polyethylene glycol coated iron oxide nanoparticles (PEG-IONPs) in hydrogen peroxide presence. The influence of PEG with different molecular weights has been studied for the oxidation of adrenaline. A slightly modified co-precipitation method was employed to synthesize PEG-IONPs that were characterized using TEM, XRD, FTIR, TGA, and VSM analyses. Oxidation rate of adrenaline was examined with bare-IONPs and PEG-IONPs using H2O2in aqueous and surfactant media. Cetyltrimethyl ammonium bromide (CTABr), sodium dodecyl sulphate (SDS), and Triton X-100 (TX100) were used at premicellar concentrations. The existence of PEG on the surface of IONPs decreased the rate of reaction. Also, the improvement in molecular weight of PEG further declined the reaction rate. The addition of surfactants increased the oxidation rate in the copresence of bare-IONPs, however, decreased the rate with increasing molecular weight of the polymer. Thus, higher molecular weight PEG-supported PEG-IONPs could be used to decrease the oxidation of adrenaline.
Nanotechnology is a broad interdisciplinary field with many applications in science & technology. These Nanoparticles are 1-100nm in dimension. Locally available plant namely Thespesia populnea commonly called Portia tree leaves and figs were taken for nanoparticle isolation. The solvent most widely used are water, Copper sulphate & Manganese oxide mixture at PH 5 -7, temperature between 50-700 C and Concentrations 1:2, 1:3 respectively. The mixtures after incubation centrifuged and the pellet was dried in oven at 70℃ for 2hours and the formed copper and Manganese nanoparticles were isolated. Totally 32 samples of copper & Manganese nanoparticles with different parameters have been collected. 0.1g of each sample is taken and 1ml of DMSO (Dimethyl Sulfoxide) to each tube and mixed them thoroughly. Then 10µl of the prepared solution was added and the sample is subjected to UV-Visible spectrophotometer at 200nm, 220nm, 240nm, 250nm, 300nm, 350nm and 400nm, SEM at 500 – 94,300X, XRD at 2ɵ = 100– 900 for characterization. Antibacterial and antifungal activity performed i.e sterilized and solidified nutrient agar and PDA loaded with 100µl of Gram positive bacteria, Gram negative bacteria, fungal organisms through disc diffusion method. Cu NP’s acts against upon Gram positive Bacteria Clostridium Perfringens, Gram negative Bateria Aeromonas hydrophila, Salmonella enterica & Fungi like Phytophthora infestans and Mn NP’s acts against upon Gram positive bacteria Bacillus subtilis , Gram negative bateria Salmonella enterica & Fungi like Candida albicans
The latest findings in iron metabolism and the newly uncovered process of ferroptosis have paved the way for new potential strategies in anti-leukemia treatments. In the current project, we reviewed and summarized the current role of nanomedicine in the treatment and diagnosis of leukemia through a comparison made between traditional approaches applied in the treatment and diagnosis of leukemia via the existing investigations about the ferroptosis molecular mechanisms involved in various anti-tumor treatments. The application of nanotechnology and other novel technologies may provide a new direction in ferroptosis-driven leukemia therapies. The article explores the potential of targeting ferroptosis, a new form of regulated cell death, as a new therapeutic strategy for leukemia. It discusses the mechanisms of ferroptosis and its role in leukemia and how nanotechnology can enhance the delivery and efficacy of ferroptosis-inducing agents. The article not only highlights the promise of ferroptosis-targeted therapies and nanotechnology in revolutionizing leukemia treatment, but also calls for further research to overcome challenges and fully realize the clinical potential of this innovative approach. Finally, it discusses the challenges and opportunities in clinical applications of ferroptosis.
Many aspects of how magnetic particles, particularly magnetite particles, are distributed in living organisms and how they affect brain function and neurodegenerative diseases remain unclear. There is an urgent need to develop new methods and techniques to non-invasively and highly accurately detect the presence of these magnetic particles and estimate their location. In this study, we adopted Nearest Neighbors as a machine learning algorithm and analyzed the inverse problem of the machine learning model to estimate the position of magnetic particles that are the source of biomagnetic signals. By arranging the magnetic sensors in three dimensions, the percentage of position estimation errors of 1 cm or less increased, even though there were only 8 magnetic sensors, and the average position estimation error per horizontal plane was approximately 8 mm. Since the resolution of conventional magnetoencephalography equipment is 5 to 7 mm, and measurements are performed using approximately 150 SQUID sensors, it is possible to improve position estimation accuracy by adjusting the placement conditions of the magnetic sensors.
Tetrapeptide Arg-Gly-Asp-Ser (RGDS) exhibiting cell-attachment activity was immobilized to poly(vinyl alcohol) (PVA), and to ethylene-acrylic acid copolymer (PEA) conaining 2.84 mol% acrylic acid. RGDS was also immobilized to PEA via Gly-Gly-Gly (GGG) as a spacer. Adsorption behaviors of plasma proteins, albumin and γ-globulin, on these peptide-immobilized PVA and PEA surfaces were examined in phosphate buffer solution by means of interfacial pressure. It was found that the interfacial pressures of these polymer surfaces were drastically lowered by immobilizing the peptides, RGDS and GGGRGDS.
The discovery of the nanoworld in the past decade or so has depended to a large extent on the invention of the atomic force microscope and a variety of methods to fabricate nanostructures.
Fluids with ferromagnetic properties may be formed by a colloidal suspension of solid magnetic particles such as magnetite in a parent liquid. The viscosity of the fluid in a magnetic field is predicted by dimensional analysis to be a function of the ratio of hydrodynamic stress to magnetic stress, . The prediction is verified experimentally and from the correlated data it is determined that for values of this ratie greater than 10−4 there is no change of viscosity in an applied field. For values between 10−6 and 10−4 the viscosity is a function of both magnetic field and rate of shear. Theoretically, for high values of applied field, the viscosity again becomes independent of field or shear rate.
Mössbauer-effect measurements on extremely small (~60 Å) crystallites of gamma-Fe2O3 show that the spin configuration differs from the Néel type found in large crystallites. It is proposed that the ions in the surface layer are inclined at various angles to the direction of the net moment.
The development of functionalized nanoparticles has made it possible to design target specific markers for detecting morphological and physiological changes in vivo using magnetic resonance imaging (MRI). The proposed technique is very useful for detecting tumors and can even be used for detecting metabolic functional alterations in the brain such as epileptic activity. Nonionic surfactant coated superparamagnetic nanoparticles with narrow size distribution were prepared by chemical coprecipitation method as a diagnostic tracer for MRI imaging. Imaging results indicate that the nanoparticles have a superparamagnetic property that is detectable in an MRI scanner, thus to be a suitable substrate for MR contrast agents.
Quantification of apoptotic cell death in vivo has become an important area of investigation in patients with acute lymphoblastic leukemia (ALL). We have devised a noninvasive analytical method to estimate the percentage of apoptotic lymphoblasts in doxorubicin-treated Jurkat T-cell ALL cultures, using proton nuclear magnetic resonance spectroscopy (1H NMR). We have found that the ratio of the methylene (CH2 ) resonance (at 1.3 ppm) to the methyl (CH3 ) resonance (at 0.9 ppm) signal intensity, as observed by 1H NMR, is directly proportional to the percentage of apoptotic lymphoblasts in vitro. The correlation between the CH2/CH3 signal intensity ratio and the percentage of apoptotic lymphoblasts was optimal 24 to 28 hours after doxorubicin treatment (r2 = .947, N = 27 samples). There was also a direct temporal relationship between an increase in the CH2/CH3 signal intensity ratio and the onset of apoptosis as detected by nuclear morphologic analysis, fluorescein-annexin V flow cytometry, and DNA gel electrophoresis. Thin-layer chromatography confirmed that a dynamic and/or compositional change of the plasma membrane, rather than increases in lipase activity or fatty acid production, appears to account for the increase in the CH2/CH3 signal intensity ratio during apoptosis. 1H NMR may have clinical utility for the early noninvasive assessment of chemotherapeutic efficacy in patients with ALL.
Nanophase Materials is the first and, as yet, the only comprehensive book published in this new and exciting area of materials science. It gives a broad overview of the revolutionary new field of nanophase materials; a view which spans the materials, physics, and chemistry research communities at a tutorial level that is suitable for advanced undergraduates, graduate students, postdoctoral researchers, and experts or would-be experts in the science of nanostructured materials. The articles are authored by many of the world's most prominent scientists in this field. The book covers the diverse methods for synthesizing nanophase materials, a variety of subsequent processing methodologies, what is known about the structures of these materials on various length scales from atomic to macroscopic, and the properties of these unique and novel materials. The materials properties covered are mechanical, electronic, optical, and magnetic and hence span a wide range of important new opportunities for technological applications.
Timely information on scientific and engineering developments occurring in laboratories around the world provides critical input to maintaining the economic and technological strength of the United States. Moreover, sharing this information quickly with other countries can greatly enhance the productivity of scientists and engineers. These are some of the reasons why the National Science Foundation (NSF) has been involved in funding science and technology assessments comparing the United States and foreign countries since the early 1980s. A substantial number of these studies have been conducted by the World Technology Evaluation Center (WTEC) managed by Loyola College through a cooperative agreement with NSF. The National Science and Technology Council (NSTC), Committee on Technology's Interagency Working Group on NanoScience, Engineering and Technology (CT/IWGN) worked with WTEC to develop the scope of this Nanostucture Science and Technology report in an effort to develop a baseline of understanding for how to strategically make Federal nanoscale R&D investments in the coming years. The purpose of the NSTC/WTEC activity is to assess R&D efforts in other countries in specific areas of technology, to compare these efforts and their results to U. S. research in the same areas, and to identify opportunities for international collaboration in precompetitive research. Many U. S. organizations support substantial data gathering and analysis efforts focusing on nations such as Japan. But often the results of these studies are not widely available. At the same time, government and privately sponsored studies that are in the public domain tend to be "input" studies.
We present a study on the magnetic behavior of nanosized iron oxide particles coated with different surfactants (sodium oleate, PVA and starch) in a ferrofluid. The effect of the coating material, and different particle concentrations in the ferrofluid have been magnetically investigated to determine the effective magnetic particle size and possible interaction. The superparamagnetic iron oxide particles, synthesized by a controlled co-precipitation technique, are found to contain magnetic (Fe3O4) as a main phase with a narrow physical particle size distribution between 6 and 8 nm. The mean effective magnetic size of the particles in different ferrofluid systems are estimated to be around 4-5 nm which is smaller than the physical particle size. On a 10% dilution in the starch coated ferrofluid we observe a decrease in the blocking temperature.
Magnetic fluids (ferrofluids), which are stable suspensions of single-domain particles of magnetic materials, are now well-established in a number of devices. However, in devices where ultra-stability is required in the presence of magnetic fields, the presence of aggregates and/or phase-separation may impose limitations on their usefulness. Their usefulness is further constrained by the limited temperature range over which fluids remain stable.
Cytokines are growth factors which regulate proliferation, differentiation and function of cells of the blood and the immune system.
Poly(ethylene glycol) (PEG) is a highly investigated polymer for the covalent modification of biological macromolecules and surfaces for many pharmaceutical and biotechnical applications. In the modification of biological macromolecules, peptides and proteins are of extreme importance. Reasons for PEGylation (i.e. the covalent attachment of PEG) of peptides and proteins are numerous and include shielding of antigenic and immunogenic epitopes, shielding receptor-mediated uptake by the reticuloendothelial system (RES), and preventing recognition and degradation by proteolytic enzymes. PEG conjugation also increases the apparent size of the polypeptide, thus reducing the renal filtration and altering biodistribution. An important aspect of PEGylation is the incorporation of various PEG functional groups that are used to attach the PEG to the peptide or protein. In this paper, we review PEG chemistry and methods of preparation with a particular focus on new (second-generation) PEG derivatives, reversible conjugation and PEG structures. (C) 2002 Published by Elsevier B.V.
New biodegradable magnetic nanospheres were synthesized for the application in the magnetic field assisted radionuclide therapy. For this purpose, superparamagnetic iron oxide cores were coated with several hydrophilic polymers, such as dextran, starch, chitosan, ficoll, polyethylene imine and polyvinylpyrrolidone. The different surface properties of these magnetic polymer nanospheres were demonstrated by a significant variation of the electrophoretic mobility of the particles in dependence on the pH-value.
This book addresses the interface between chemical engineering and cell biology, demonstrating how a mathematical modeling approach combined with quantitative experiments can provide enhanced understanding of cell phenomena involving receptor-ligand interactions. The work introduces engineers to key problems in receptor biology, and familiarizes cell biologists with the valuable insights that can be gained from engineering analysis and synthesis. The central unifying theme is the development of a quantitative understanding of how receptor-mediated cell functions depend on receptor and ligand molecular properties. Both basic and newly developed model frameworks are described over the entire spectrum of receptor processes, from fundamental cell-surface binding, intracellular trafficking, and signal transduction events to the cell behavioral functions they govern, including proliferation, adhesion, and migration. Emphasis is placed on mechanistic models that are accessible to testing. Researchers in the fields of biotechnology, biomedicine, bioengineering, and molecular biology will find the information presented here highly useful and clearly described.
Polyethylene oxide presents interesting properties in relation to biological macromolecules and cells, and especially in relation to blood proteins and platelets. The forms of polyethylene oxide considered in this review include free homogeneous solution as well as polymers adsorbed from solutions onto surfaces, covalently bound to surfaces, or formed into virtual networks by phase separation of block copolymers. Cumulative evidence indicates a very low level of interaction between polyethylene oxide and biological species studied (molecular, cellular). Thus, this polymer is potentially important as a biomaterial.
Oleic acid and stearic acid are similar surfactants which, however, lead respectively to stability and to precipitation of ferrofluid suspensions: to understand this, the forces between layers of oleic-like surfactants and between layers of stearic-like surfactants across a hexadecane (HD) medium were measured using a surface force balance (SFB). Separate measurements reveal that only the oleic layers are solvated by HD, while the SFB results reveal that for both surfactants a marked net attraction is present between the surfaces. Simple considerations based on these observations explain why, despite this attraction, ferrofluid dispersions are stabilized by oleic but not by stearic surfactants.
We present a study on the magnetic behavior of nanosized iron oxide particles coated with different surfactants (sodium oleate, PVA and starch) in a ferrofluid. The effect of the coating material, and different particle concentrations in the ferrofluid have been magnetically investigated to determine the effective magnetic particle size and possible interaction. The superparamagnetic iron oxide particles, synthesized by a controlled co-precipitation technique, are found to contain magnetic (Fe3O4) as a main phase with a narrow physical particle size distribution between 6 and 8 nm. The mean effective magnetic size of the particles in different ferrofluid systems are estimated to be around 4-5 nm which is smaller than the physical particle size. On a 10% dilution in the starch coated ferrofluid we observe a decrease in the blocking temperature.
Surface‐modified nanoparticles have received much attention as drug carriers. Natural and synthetic polymers are used as the materials to prepare nanoparticles and the properties of these nanoparticles originate with these polymeric materials. In particular, these nanoparticles are modified for specific objectives. The surface characteristics of (shell) nanoparticles are more important than those of the core, because the shell layer directly contacts body fluids and organs. Generally, the nanoparticles are coated with hydrophilic polymer to give long circulation and/or are conjugated with functional ligands or proteins for site‐specific delivery. In this review, the preparative methods and the applications of surface modification of polymeric functionalized nanoparticles for long‐circulation, site‐specific delivery, and oral delivery are discussed.
Magnetic nanoparticles have been proposed for use as biomedical purposes to a large extent for several years. In recent years, nanotechnology has developed to a stage that makes it possible to produce, characterize and specifically tailor the functional properties of nanoparticles for clinical applications. This has led to various opportunities such as improving the quality of magnetic resonance imaging, hyperthermic treatment for malignant cells, site-specific drug delivery and the manipulation of cell membranes. To this end a variety of iron oxide particles have been synthesized. A common failure in targeted systems is due to the opsonization of the particles on entry into the bloodstream, rendering the particles recognizable by the body's major defence system, the reticulo-endothelial system. This review discusses each of the above bio-applications of such magnetic nanoparticles and details some of the main recent advances in biological research.
We study the magnetic properties of dispersions of uniformly sized,
chemically synthesized cobalt nanoparticles (NP's), observing a
crossover from a blocked state to a superparamagnetic one with
increasing temperature. By analyzing magnetization data, we determine
the distributions of NP volumes and anisotropies, and establish that
variations in the shapes of the magnetic cores of the NP's generate the
anisotropy governing the crossover. We characterize the frustrated
low-temperature state produced by the competition between dipolar
interactions and anisotropy at sufficiently high NP density through
remanent magnetization measurements, and explain the results through
analysis of a simple model.
Work on the synthesis, properties, and applications of nanophase
materials has developed rapidly during the past decade. A wide variety
of methods now exist for their production, including several
plasma-based processes. The possibilities for engineering new materials
with unique or improved properties for a number of applications is now
evident from the extant research results. A brief review is presented
here along with some examples of useful application areas and some
thoughts for the future of this field.
ELECTROMAGNETISM: MAGNETIC PHENOMENA ON THE MACROSCOPIC SCALE Magnetic Fields Magnetic Field Magnetic Induction Magnetic Field Calculations References Further Reading Exercises Magnetization and Magnetic Moment Magnetic Moment Magnetic Poles and Amperian Bound Currents Magnetization Magnetic Circuits and the Demagnetizing Field Penetration of Alternating Magnetic Fields into Materials References Further Reading Exercises Magnetic Measurements Induction Methods Force Methods Methods Depending on Changes in Material Properties Superconducting Quantum Interference Devices References Further Reading Exercises Magnetic Materials Classification of Magnetic Materials Magnetic Properties of Ferromagnets Different Types of Ferromagnetic Materials for Applications Paramagnetism and Diamagnetism References Further Reading Exercises MAGNETISM IN MATERIALS: MAGNETIC PHENOMENA ON THE MICROSCOPIC SCALE Magnetic Properties Hysteresis and Related Properties Barkhausen Effect and Related Phenomena Magnetostriction Magnetoresistance References Further Reading Exercises Magnetic Domains Development of Domain Theory Energy Considerations and Domain Patterns References Further Reading Exercises Domain Walls Properties of Domain Boundaries Domain-Wall Motion References Further Reading Exercises Domain Processes Reversible and Irreversible Domain Processes Determination of Magnetization Curves from Pinning Models Theory of Ferromagnetic Hysteresis Dynamics of Domain Magnetization Processes References Further Reading Exercises Magnetic Order and Critical Phenomena Theories of Paramagnetism and Diamagnetism Theories of Ordered Magnetism Magnetic Structure References Further Reading Exercises Electronic Magnetic Moments Classical Model of Magnetic Moments of Electrons Quantum Mechanical Model of Magnetic Moments of Electrons Magnetic Properties of Free Atoms References Further Reading Exercises Quantum Theory of Magnetism Electron-Electron Interactions Localized Electron Theory Itinerant Electron Theory References Further Reading Exercises MAGNETICS: TECHNOLOGICAL APPLICATIONS Soft Magnetic Materials Properties and Applications of Soft Magnets Materials for AC Applications Materials for DC Applications Materials for Magnetic Shielding References Further Reading Materials Conferences Hard Magnetic Materials Properties and Applications of Hard Magnets Permanent Magnet Materials References Further Reading Materials Conferences Magnetic Recording History of Magnetic Recording Magnetic Recording Media Recording Heads and the Recording Process Modeling the Magnetic Recording Process References Further Reading Magnetic Evaluation of Materials Methods for Evaluation of Materials Properties Methods for Detection of Flaws and Other Inhomogeneities Magnetic Imaging Methods Sensitivity to Microstructure and Material Treatment References Further Reading Solutions to Exercises
Unilamellar vesicles, formed spontaneously by mixing single-tailed anionic and cationic surfactants (dodecylbenzenesulfonic acid (HDBS) and cetyltrimethylammonium bromide (CTAB), respectively), have been used as reactors for the synthesis of magnetic nanoparticles. The micellar cationic surfactant solution containing ferrous chloride was mixed with the micellar anionic surfactant solution, resulting in the formation of defect-free unilamellar vesicles, with ferrous chloride within the cores as well as in the extravesicular spaces. The external ferrous ions were replaced with sodium ions by gel permeation chromatography. Sodium hydroxide was then added to the extravesicular region. Hydroxyl ions penetrated the vesicle cores and reacted with the available ferrous ions to initiate particle formation. The presence of intravesicular particles was confirmed by cryogenic transmission electron microscopy. Absorbance measurement showed that the reaction proceeded over a period of several minutes. To form the magnetic nanoparticles, the suspension was heated to about 70°C for 1 min, and then cooled back to room temperature. The resulting particles had a mean diameter of approximately 2.6 nm and displayed superparamagnetic behavior. Wide-area electron diffraction showed the particles to be either γ-ferrite or magnetite. Magnetization measurements yielded a least upper bound for the magnetic diameter of these particles of 0.61 nm. These results are consistent with the presence of a magnetically disordered surface layer on the order of 1 nm thick.
Aqueous solutions of , , or chloride and nitrate were encapsulated inside unilamellar vesicles and made to react with hydroxyl ions diffusing into the intravesicular space through the vesicle walls. The normal intravesicular coprecipitation product was nanometer-sized, nearly spherical crystalline particles, with one particle in each vesicle. The particle sizes are controllable and their size distribution remained unchanged over several days. Both the cationic species were incorporated, and, with one exception, the divalent/trivalent component ratio was higher in the intravesicular product than that in the original solution. In contrast, when the same reactant solutions were brought together for free precipitation, two distinct phases and particle morphologies resulted—each corresponding to the expected single cation hydroxide, and both radically different from the intravesicular product. Thus coprecipitation inside vesicles opens up the possibility of combining two normally “incompatible” components into one particle with the maximum scale of heterogeneity equal to the vesicle inner diameter—a low-temperature homogenization technique. It was possible to precipitate barium hydroxide in the intravesicular space when the initial solution had a barium ion concentration below its solubility, while a free reaction at the same concentration did not yield any precipitate. The ability to overcome traditional solubility limitations can be exploited for the production of unique phases. Except in a few cases, it was difficult to match electron diffraction patterns for the intravesicular product with those of known compounds, further confirming the possibility of making novel phases by this technique. By increasing the outflux of the chloride ions and hence enhancing the influx of the hydroxyl ions, it was possible to nucleate more than one particle in each vesicle—a potentially useful feature for forming polycrystalline or amorphous nanocomposites.
The use of nanometre thick silica shells as a means to stabilize metal clusters and semiconductor particles is discussed, and its potential advantages over conventional organic capping agents are presented. Shell deposition depends on control of the double layer potential, and requires priming of the core particle surface. Chemical reactions are possible within the core, via diffusion of reactants through the shell layer. Quantum dots can be stabilized against photochemical degradation through silica deposition, whilst retaining strong fluorescence quantum yields and their size dependent optical properties. Ordered 3D and 2D arrays of a macroscopic size with uniform particle spacing can be created. Thin colloid films can also be created with well-defined interparticle spacing, allowing controlled coupling of exciton and surface plasmon modes to be investigated. A number of future core–shell nanocomposite structures are postulated, including quantum bubbles and single electron capacitors based on Au@SiO2.
Iron oxide films have been grown onto MgO and oxidized silicon substrates using pulsed laser deposition with a 248 nm excimer laser. The films were deposited in a vacuum from an α-Fe2O3 target. Films grown epitaxially on MgO consisted of the ferrimagnetic Γ-Fe2O3 phase, with an average saturation magnetization of 353±26 kA/m. The Faraday rotation of the Γ-Fe2O3 films was measured at 645 nm and 1550 nm wavelengths, and was found to be 4 and 2.5 degrees/μm, respectively. It is assumed that the high Faraday rotation, accompanied by a relatively high absorption, is associated with a transition of Fe2+ ions in octahedral sites.
Magnetic nanoparticles have been proposed for use as biomedical purposes to a large extent for several years. In recent years, nanotechnology has developed to a stage that makes it possible to produce, characterize and specifically tailor the functional properties of nanoparticles for clinical applications. This has led to various opportunities such as improving the quality of magnetic resonance imaging, hyperthermic treatment for malignant cells, site-specific drug delivery and the manipulation of cell membranes. To this end a variety of iron oxide particles have been synthesized. A common failure in targeted systems is due to the opsonization of the particles on entry into the bloodstream, rendering the particles recognizable by the body's major defence system, the reticulo-endothelial system. This review discusses each of the above bio-applications of such magnetic nanoparticles and details some of the main recent advances in biological research.
In recent years, interest in the preparation and characterization of nanostructured materials has grown due to their distinctive properties and potential technological applications. Nanoscale materials represent a new realm of matter and offer widespread possibilities for contributions to science and technology. Nanoscale Materials in Chemistry explores the vast potential of nanomaterials and serves as essential reading for the entire science community. The extensive coverage of Nanoscale Materials in Chemistry presents a thorough introduction to the field of nanostructured materials, including chemical synthesis methods, bonding theories, and applications. Because nanomaterials are finding more applications in the real world, this text contains up-to-date treatment of such topics as: Metals, semiconductor nanocrystals, and ceramics Double layers, optical properties, and the electrochemistry of metal nanoparticles Chemical and catalytic aspects of nanocrystals Specific heats and melting points of nanocrystalline materials Authored by world-renowned experts in the field of nanotechnology, Nanoscale Materials in Chemistry is suitable as a primary text for graduate courses and is a reliable resource for scientists.
Fine equiaxed gamma-CoxFe2-xO3 (x=0, 0.06) particles with diameters of 200-1000 Å were prepared by chemical precipitation. The average crystallite sizes of the particles were determined from X-ray line broadening measurements. The saturation magnetization of the particles were measured at 295 and 79 K, respectively. An empirical linear dependence of the specific saturation magnetization sigmas on the specific surface area Sa of the fine crystallites was obtained in the form of sigmas(S) = sigmas(∞)(1 - ASa), where the slope A is different for gamma-Fe2O3 and gamma-Co 0.06Fe1.94O3 particles. Under the supposition that the fine crystallite consists of two parts, i.e. a surface layer, whose magnetic moment can not be turned entirely along the direction of the applied field, but makes an average canting angle with the field, and an inner part, whose magnetic moment can be aligned along the direction of the applied field, the above empirical formula can be interpreted well.
A microelectromagnet matrix and a ring trap that position and control magnetic nanoparticles are demonstrated. They consist of multiple layers of lithographically defined Au wires separated by transparent, insulating polyimide layers on sapphire substrates. Magnetic field patterns produced by these devices allow microscopically precise control and manipulation of magnetic nanoparticles. A microelectromagnet matrix produces single or multiple peaks in the magnetic field magnitude, which trap, move, and rotate magnetic nanoparticles, as well as electromagnetic fields to probe and detect particles. Microelectromagnets are new tools with which to study and manipulate nanoparticles and biological entities.
The formation of zinc oxide microcrystals obtained from hydrolysis of zinc nitrate and zinc chloride in the presence of hexamethylenetetramine has been studied by X-ray diffraction, electron microscopy and IR spectroscopy. Prisms, needles and spherulitic aggregates are formed depending on several factors such as reactant concentrations, pH and temperature. It is shown that the formation of prisms and needles is mainly determined by kinetic conditions with prisms favoured at lower temperatures (< 80 °C), where faces can be developed from the solution complexes. The formation mechanism of the monodispersed prisms and needles occurs by coupling of microcrystalline spheres through their c axes forming embryonic rod particles which later grow. On the other hand, the formation of spherulitic aggregates is more the consequence of solution heterogeneity, i.e. high reactant concentrations.
Preparation and Modification of Biodegradable Magnetic Particles: Preparation and Application of Monosized Magnetic Particles in Selective Cell Separation W.S. Prestvik, et al. Characterization of Magnetic Particles: Intravenously Injected Particles: Surface Properties and Interaction with Blood Proteins - The Key Determining the Organ Distribution R.H. Muller, et al. Applications in Cell Separation and Analysis: Physics of the Magnetic Cell Sorting M. Zborowski. Applications in Molecular Biology: Magnetic Separation in Molecular Biology M. Bosnes, et al. Biomedical Applications of Magnetic Carriers: Overview of Magnetic Separations Used in Biochemical and Biotechnological Applications I. Safarik, M. Safarikova. Drug Delivery and Radionuclide Therapy: Targeting Magnetic Microspheres to Brain Tumors S.K. Pulfer, J.M. Gallo. MRI-Contrast Agents: Magnetic Nanoparticles as Contrast Agents for MR Imaging: An Overview J.W. Bulte, R.A. Brooks. Hyperthermia: Magnetic Fluid Hyperthermia (MFH) A. Jordan, et al. 36 Additional Articles. Index.
Amorphous poly(dl-lactic acid-co-glycolic acid) copolymers are used to prepare biodegradable carriers for drug delivery formulations. A luteinizing hormone-releasing hormone agonist, triptoreline, is incorporated in small microspheres and obtained by a phase separation technique in non-aqueous medium. The microspheres are injected by the intramuscular route in the thigh of male rats. The rate of peptide release depends on the overall polymer hydrophobicity defined by the amount of residual oligomers present and technology variables. The best release results are obtained from micro-spheres prepared at 2500 rpm (high preparative stirring speed) and with polymer P2 (intermediate hydrophobicity) which ensures complete castration in rats over one month.
Acrylamide (AAm)-methacrylic acid (MAc)-methylenebisacrylamide (MBAAm) terpolymer microspheres and AAmMAc-MBAAm-nitrophenyl acrylate (NPA) quaterpolymer microspheres with high monodispersity were prepared by precipitation polymerization in alcohol. The former were modified into composite microspheres containing hydrophobic domains or magnetite nanospheres. The active ester in the quaterpolymer microspheres was allowed to undergo hydrolysis or aminolysis to prepare novel microspheres such as highly negative, amphoteric, hydrophobic or bioconjugate microspheres.
Ferrofluids containing gadolinium and iron particles in the size range 80-750 Å in diameter have been prepared by evaporating gadolinium and iron onto a mercury surface in an argon atmosphere at a controlled pressure. The particle sizes are determined by electron microscopy and identified by microprobe analysis.