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In recent years, paramagnetic nanoparticles (NPs) have been widely used for magnetic
resonance imaging (MRI). This paper reports the fabrication and toxicity evaluation of polyethylene
glycol (PEG)-functionalized holmium oxide (Ho2O3) NPs for potential T2-weighted MRI applications.
Various characterization techniques were used to examine the morpho...
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The design of graphene-based nanomaterials for biomedical purposes is of great interest. Graphene oxide (GO) nanosheets represent the most widespread type of graphene materials in biological investigations. In the present study, GO nanosheets were synthesized and subsequently chemically functionalized with carboxymethylated dextran (CMD) molecules,...
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... High-purity reagents were purchased from Merck Group (St. Louis, MO, USA) and utilized without any purification. The luminescent Y 2 O 3 :Eu 3+ particles were produced using the urea homogeneous precipitation protocol [22,23]. In brief, 0.5 g of urea, 371.5 mg of yttrium nitrate hexahydrate, and 12.8 mg of europium nitrate pentahydrate were completely dissolved in 40 mL of deionized water. ...
Solar cells have been developed as a highly efficient source of alternative energy, collecting photons from sunlight and turning them into electricity. On the other hand, ultraviolet (UV) radiation has a substantial impact on solar cells by damaging their active layers and, as a result, lowering their efficiency. Potential solutions include the blocking of UV light (which can reduce the power output of solar cells) or converting UV photons into visible light using down-conversion optical materials. In this work, we propose a novel hydrophobic coating based on a polydimethylsiloxane (PDMS) layer with embedded red emitting Y2O3:Eu³⁺ (quantum yield = 78.3%) particles for UV radiation screening and conversion purposes. The favorable features of the PDMS-Y2O3:Eu³⁺ coating were examined using commercially available polycrystalline silicon solar cells, resulting in a notable increase in the power conversion efficiency (PCE) by ~9.23%. The chemical and UV stability of the developed coatings were assessed by exposing them to various chemical conditions and UV irradiation. It was found that the developed coating can endure tough environmental conditions, making it potentially useful as a UV-protective, water-repellent, and efficiency-enhancing coating for solar cells.
... Atabaev et al. reported an r 2 value of 23.47 mM −1 s −1 at 1.5 T for PEG-coated Ho 2 O 3 NPs (PEG Mn = 4000 amu) with a particle diameter of 67-81 nm [94], which is high enough to be used as T 2 MRI contrast agents. ...
In recent decades, magnetic nanoparticles (MNPs) have attracted considerable research interest as versatile substances for various biomedical applications, particularly as contrast agents in magnetic resonance imaging (MRI). Depending on their composition and particle size, most MNPs are either paramagnetic or superparamagnetic. The unique, advanced magnetic properties of MNPs, such as appreciable paramagnetic or strong superparamagnetic moments at room temperature, along with their large surface area, easy surface functionalization, and the ability to offer stronger contrast enhancements in MRI, make them superior to molecular MRI contrast agents. As a result, MNPs are promising candidates for various diagnostic and therapeutic applications. They can function as either positive (T1) or negative (T2) MRI contrast agents, producing brighter or darker MR images, respectively. In addition, they can function as dual-modal T1 and T2 MRI contrast agents, producing either brighter or darker MR images, depending on the operational mode. It is essential that the MNPs are grafted with hydrophilic and biocompatible ligands to maintain their nontoxicity and colloidal stability in aqueous media. The colloidal stability of MNPs is critical in order to achieve a high-performance MRI function. Most of the MNP-based MRI contrast agents reported in the literature are still in the developmental stage. With continuous progress being made in the detailed scientific research on them, their use in clinical settings may be realized in the future. In this study, we present an overview of the recent developments in the various types of MNP-based MRI contrast agents and their in vivo applications.
... For example, magnetic nanomaterials have been highlighted as their theranostic properties. They can be combined with fluorescent molecules or anti-tumor drugs and used as magnetic resonance imaging (MRI) agents [29][30][31]. ...
Recent advances in inorganic nanomaterial-based theranostics enabled imaging-guided molecular targeting and drug delivery, and various combinations of theranostic systems. The term “theranostics” is defined as diagnosis processed with therapy simultaneously with a specific connection between therapy and diagnosis. The inorganic nanomaterials, representatively carbon, metal, ceramic, and semiconductor-based nanomaterials, exhibit their unique characteristics to be used in theranostic applications. However, the unveiled human biosafety of nanomaterials for clinical use has become a major concern. Therefore, in this review, we compiled recent research on in vitro and in vivo biosafety of inorganic nanomaterials in various theranostic applications, along with a discussion of how the particle formulation, size, surface functionalization, test species, and test condition affect biocompatibility. Furthermore, the progress and challenges of the development of biocompatible inorganic nanomaterials for theranostic applications were discussed. In conclusion, with appropriate precautions on the biosafe condition to be administered, inorganic nanomaterials can be proposed to have excellent potential in the future theranostic application.
... 26 Most of the research on Ho 3+ chelates and their conjugates has evolved around their ability toward T2 negative contrast enhancement. 27,28 However, the potential of Ho 3+ after doping in the CD matrix is still not fully explored. Hence there is a scope to design a single matrix by combining the potential of these two individuals (Ho 3+ and CDs) and achieve optimum FL/MR properties. ...
... Generally, holmium (III) complexes and chelated are well recognized for their T2 contrast enhancement capability in MRI studies. 27,28,39 However, we encounter the T1 brightening ability of holmium-doped CDs in a concentration-dependent manner. A concentration-induced T1 brightening ability is demonstrated in Figure 4a, where CDs without any Ho 3+ trace show no contrast enhancement in the same concentration range. ...
Accurate diagnosis with secure and target-specific drug delivery improves the success rate in cancer treatment and patient survival outcomes. The development of stimuli-responsive theranostic with the molecular computing ability could address all these criteria at a time. This work attempts to design a multifunctional biocomputing agent that can serve as a secure and target-specific drug carrier and simultaneously act as a molecular logic device. Hence, we developed a novel Holmium doped Carbon dot-gelatin nanoparticle (HoCDGNPs) by two-step desolvation methods and used it as fluorescence imaging and MRI contrast agents with effective pH and Cu2+ ions sensing ability. Further, Boolean algebraic operations (NOR, OR, IMP and NIMP) are executed on the HoCDGNPs system using the fluorescence (FL)/ magnetic resonance (MR) response in the presence of different inputs (H+, OH- and Cu2+ ions), and the results are mesmerizing. Moreover, the FL quenching phenomena of HoCDGNPs in the presence of Cu2+ ions by cupric-amine or cupric-carboxylate coordination formation is also exploited in the living HeLa cells. Finally, the resulting system is used for pH-responsive drug delivery of a model anticancer drug (5-fluorouracil) and the release profile is found selective and sustained over the pH range 6 and 7.4. Thus counter the shortcomings associated with the 5-Fluorouracil drug administration (short lifetime and poor specificity at high doses). The cellular uptake and cell viability assessment are also accomplished in cancerous and noncancerous cell lines to ensure the acceptability of this multifunctional biocomputing system, and the results are pretty satisfactory.
... Certain lanthanide oxide nanoparticles are suitable MRI contrast agents because their paramagnetic moments at room temperature are sufficiently high to induce water proton spin relaxations [6][7][8][9][10][11][12], especially at high MR fields [10,11,13,14]. Their magnetic moments Figure 1 shows the one-pot polyol synthesis of PEI-coated ultrasmall Ho 2 O 3 nanoparticles. ...
Water proton spin relaxivities, colloidal stability, and biocompatibility of nanoparticle magnetic resonance imaging (MRI) contrast agents depend on surface-coating ligands. In this study, hydrophilic and biocompatible polyethylenimines (PEIs) of different sizes (Mn = 1200 and 60,000 amu) were used as surface-coating ligands for ultrasmall holmium oxide (Ho2O3) nanoparticles. The synthesized PEI1200- and PEI60000-coated ultrasmall Ho2O3 nanoparticles, with an average particle diameter of 2.05 and 1.90 nm, respectively, demonstrated low cellular cytotoxicities, good colloidal stability, and appreciable transverse water proton spin relaxivities (r2) of 13.1 and 9.9 s−1mM−1, respectively, in a 3.0 T MR field with negligible longitudinal water proton spin relaxivities (r1) (i.e., 0.1 s−1mM−1) for both samples. Consequently, for both samples, the dose-dependent contrast changes in the longitudinal (R1) and transverse (R2) relaxation rate map images were negligible and appreciable, respectively, indicating their potential as efficient transverse T2 MRI contrast agents in vitro.
... Another commonly investigated lanthanide that also displays great aptitude for ultra-high MRI, as well as a higher magnetic moment than Gd, is holmium (Ho) [213]. It has been used to perform doping on magnetic upconversion nanoparticles to create dual-mode MRI/OI (Optical Imaging) contrasts. ...
... Additionally, NaHoF 4 , HoF 3 and Ho 2 O 3 nanoparticles have been shown to be effective tools in negative contrast imaging [6,212]. Cytotoxicity studies were also conducted with the latter PEG-Ho 2 O 3 nanoparticles which demonstrated nontoxicity at concentrations inferior to 16 µg/mL [213]. ...
Magnetic nanoparticles (MNPs) have been studied for diagnostic purposes for decades. Their high surface-to-volume ratio, dispersibility, ability to interact with various molecules and superparamagnetic properties are at the core of what makes MNPs so promising. They have been applied in a multitude of areas in medicine, particularly Magnetic Resonance Imaging (MRI). Iron oxide nanoparticles (IONPs) are the most well-accepted based on their excellent superparamagnetic properties and low toxicity. Nevertheless, IONPs are facing many challenges that make their entry into the market difficult. To overcome these challenges, research has focused on developing MNPs with better safety profiles and enhanced magnetic properties. One particularly important strategy includes doping MNPs (particularly IONPs) with other metallic elements, such as cobalt (Co) and manganese (Mn), to reduce the iron (Fe) content released into the body resulting in the creation of multimodal nanoparticles with unique properties. Another approach includes the development of MNPs using other metals besides Fe, that possess great magnetic or other imaging properties. The future of this field seems to be the production of MNPs which can be used as multipurpose platforms that can combine different uses of MRI or different imaging techniques to design more effective and complete diagnostic tests.
... The r 2 value of lanthanide oxide NPs is very sensitive to the particle diameter because bigger NPs can have larger M NP values. The M NP can be approximately estimated assuming a spherical shape for NPs and using d avg as follows: M NP ≈ µ × [number (n) of Ln 3+ per NP] and n ≈ (2/5) × (d avg /w) 3 (Table 2) [49,53,54]. Compared to r 2 values of D-glucuronic acid-coated Ln 2 O 3 NPs (Ln = Tb and Ho) [49] with similar particle diameters as those of PAA-coated Ln 2 O 3 NPs, the PAA-coated NPs exhibited lower r 2 values due to their larger coating ligands, explained as follows. ...
... However, D-glucuronic acid with a smaller size than PAA can allow more water molecules to closely approach the NP, making more water molecules feel stronger magnetic fields (B) generated by the NP, consequently making the D-glucuronic acid-coated NPs have a higher r 2 value. On the other hand, large NPs and nanorods [53,54] exhibited high r 2 values even with a large ligand coating because of their enhanced paramagnetic magnetic moment per NP or per nanorod, which increases with increasing particle size and because the r 2 value is proportional to the square of the magnetic moment [14]. ...
Polyacrylic acid (PAA)-coated lanthanide oxide (Ln2O3) nanoparticles (NPs) (Ln = Tb and Ho) with high colloidal stability and good biocompatibility were synthesized, characterized, and investigated as a new class of negative (T2) magnetic resonance imaging (MRI) contrast agents at high MR fields. Their r2 values were appreciable at a 3.0 T MR field and higher at a 9.4 T MR field, whereas their r1 values were negligible at all MR fields, indicating their exclusive induction of T2 relaxations with negligible induction of T1 relaxations. Their effectiveness as T2 MRI contrast agents at high MR fields was confirmed from strong negative contrast enhancements in in vivo T2 MR images at a 9.4 T MR field after intravenous administration into mice tails.
... For example, small Gd 2 O 3 NPs are often used as potential contrast agents for magnetic resonance imaging (MRI), and computed tomography (CT) [3,4]. Other nanostructures based on lanthanides such as Dy 2 O 3 , Yb 2 O 3 , Eu 2 O 3 , Ho 2 O 3 , and their mixtures were also efficient for CT, MRI, and optical imaging of cells [4][5][6][7][8]. In general, some lanthanide oxide-based NPs show higher water proton relaxivity rates as compared to their molecular counterparts [9]. ...
... Therefore, a green approach should be introduced for the fabrication of lanthanide-based contrast agents. From Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. this point of view, environment-friendly and low-cost urea homogeneous precipitation is an attractive method for the preparation of lanthanide oxides [8,11]. In this method, urea dissolved in water is decomposed at elevated temperatures, which slowly increases the pH of the solution. ...
... Numerous reports suggested that the toxicity of the NPs strongly depends on different parameters such as size, shape, and surface functional groups [12][13][14]. Various surface functional groups such as polyacrylic acid (PAA), polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and polyethyleneimine (PEI) are commonly used to improve the biocompatibility and colloidal stability of nanostructures [4,8,[15][16][17]. Among them, a cationic polymer such as polyethyleneimine (PEI) can create positive charges on the surface resulting in steric and electrostatic stabilization of nanostructures. ...
Rare-earth metal oxide nanoparticles considered promising contrast agents for x-ray computed tomography (CT) and magnetic resonance imaging (MRI). The main purpose of this study is to investigate the potential applicability of polyethyleneimine (PEI)-coated Eu 2 O 3 and Dy 2 O 3 nanoparticles (NPs) for CT x-ray attenuation. Morphology and other physicochemical properties of prepared samples were systematically investigated using a range of characterization tools. Preliminary cytotoxicity experiments with L-929 fibroblastic cells suggested that both samples have no significant toxicity at concentrations below 100 μ g ml ⁻¹ . Clinical CT analysis shows that PEI@Eu 2 O 3 NPs exhibit higher x-ray attenuation efficiency (∼8 HU mM ⁻¹ ) as compared to PEI@Dy 2 O 3 NPs (∼5 HU mM ⁻¹ ).
... Contrasted and Fe-or Mn-based contrast operators, Gd 2 O 3 -NPs are very biocompatible. Specifically, Gd 2 O 3 -NPs with a size littler than 5 nm have a diminished attractive minute and an unequivocally smothered T 2 impact, and can be utilized for T 1 -enhanced MRI contrast [14][15][16][17] This will be significantly more worthwhile than superparamagnetic Fe 3 O 4 -NPs utilized for T 2 -enhanced MR imaging that creates obscured MR imaging contrast. Earlier, Taeghwan et al. revealed the advancement of ultrasmall Gd 2 O 3 -NPs with a size scope of 3.5-5.2 ...
Herein we report the synthesis and characterization of the antifouling Gadolinium oxide (Gd2O3) nanoparticles (NPs) modified with PEG with improved biocompatibility for MR imaging purposes. In this report, using the solvothermal decomposition of Gadolinium (III) in the presence of Na3cit, monitored by surface modification with PEG and L-Cys. The synthesized nanoparticles were confirmed by the TEM, DLS and UV-Visible spectroscopy. The morphological results show normal distance across of the flawless Gd2O3-PEG-Cys-NPs show 7.9 ± 0.4 nm, discretely, with a thin size exchange. This infers the surface adjustment does not obviously alteration the center size of the Gd2O3-NPs when contrasted with the perfect sodium citrate-balanced out Gd2O3-NPs. The Gd2O3-PEG-L-Cys-NPs are highly stable at room temperature, water dispersible and importantly less cytotoxic at high concentration of the NPs. The T1-weighted MR phantasm readings evidentially displayed that the formed PEG coated Gd2O3-PEG and Gd2O3-PEG-Cys-NPs with and without Cys may be performed as the promising T1-weighted MR imaging. The NPs displays no signs of toxicity against the human blood, which represents the biocompatibility for the human medicine applications. The Gd2O3-PEG-Cys-NPs shows relatively, high r1 acceptable cytocompatibility, target specific cancer cells and activate the dual mode MR imaging of lung metastasis cancer model in vitro. The development of versatile zwitterion functionalized Gd2O3 may be promising as an active nanoparticle probe for improved multi-model of MR imaging agents for various cancer diseases.
... Furthermore, the biocompatible and multicolor C-dots can be also concurrently used in controlled drug delivery and multimodal imaging. The development of magnetic doped C-dots can be used not only for fluorescence imaging probe but also for T1 and T2-weighted MRI (positive and negative contrast agents) [76,77]. ...
Rapid and recent progress in fluorescence microscopic techniques has allowed for routine discovery and viewing of biological structures and processes in unprecedented spatiotemporal resolution. In these imaging techniques, fluorescent nanoparticles (NPs) play important roles in the improvement of reporting systems. A short overview of recently developed fluorescent NPs used for advanced in vivo imaging will be discussed in this mini-review. The discussion begins with the contribution of fluorescence imaging in exploring the fate of NPs in biological systems. NP applications for in vivo imaging, including cell labeling, multimodal imaging and theranostic agents, are then discussed. Finally, despite all of the advancements in bioimaging, some unsolved challenges will be briefly discussed concerning future research directions.
