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TEM image and electron diffraction pattern of the purified gold nanoparticles. (a) TEM image showing the morphology of the gold crystals. (b) Electron diffraction pattern from the GNPs showing the (111), (200), (220), (311), and (222) reflections of gold.
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In the quest for producing an effective clinically relevant therapeutic agent, scalability, repeatability, and stability are paramount. In this paper, gold nanoparticles (GNPs) with precisely controlled near infrared (NIR) absorption are synthesized by a single step reaction of HAuCl4 and Na2S2O3, without assistance of additional templates, capping...
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... centrifuga- tion, the NIR peak of the GNPs shifted from 850 to 890 nm, accompanying a great decrease in the inten- sity of the SPR band at 530 nm. Figure 6a shows the Z-contrast STEM images after purification. Different species of gold particles are clearly present. ...Context 2
... of the small spherical colloid GNPs were removed after cen- trifugation. Figure 6b shows the diffraction pattern obtained from the purified GNPs, with rings correspond- ing to the (111), (200), (220), (311), and (222) reflections of the face-centered-cubic (fcc) structure of gold. Figure 7a shows a high-resolution TEM image of the vertex of one of the nanoplate structure with well- resolved (111)-type crystallographic planes (measured D-spacing of about 2.35 Å, as shown in Figure 7b), which run parallel to the long sidewalls of the struc- tures. ...Similar publications
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In order to understand more deeply the surface enhanced Raman scattering (SERS) effect, this article develops a model, based upon the simulation of the UV–visible extinction spectra which allows the determination of the morphology of metallic particles in silver and gold colloids either unaggregated or in any aggregation state. The main assumptions...
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Citations
... Various synthesis procedures are available for nanoprisms, such as microwave-assisted methods, thermal synthesis, and chemical methods. Zhang et al. synthesized nanoprisms using a one-pot seedless method using sodium thiosulfate as a reducing agent [19]. Since the nanoprisms can be synthesized as surfactant-free through this technique, their surface can easily be functionalized with suitable cross linkers for bioconjugation and provide high sensitivity. ...
... Gold nanoprisms were prepared using HAuCl 4 and sodium thiosulfate (Na 2 S 2 O 3 ) solutions, as explained by Zhang et al. [19]. For the synthesis, three sets of 5 mL each of 1.71 mM of HAuCl 4 were prepared in ultrapure water (Mili-Q, 18.2 MΩ). ...
... The increase in the band maxima of the longitudinal LSPR band is due to the increase in the edge length of the nanoprisms [48]. The shape separation of nanoprisms was performed by centrifuging solution at 3500 rpm [19]. The residue containing nanoprisms was separated after centrifugation. ...
The localized surface plasmon resonance (LSPR) is an optical phenomenon observed in noble metal nanoparticles such as gold, silver, copper, and platinum. In LSPR, the metal nanoparticles show strong electric field enhancement and extinction. The LSPR peaks of metal nanoparticles are sensitive to their size, shape and refractive index (RI) of the medium. Any changes in these parameters can be observed as the shift in the LSPR peaks of nanoparticles and used for sensing applications. Among different plasmonic metal nanoparticles, gold nanoparticles are the most suitable candidates for fabricating LSPR-based biosensors due to their exceptional long-term stability and biocompatibility. In this paper, we synthesized different shapes and sizes of gold nanoparticles, such as nanospheres, nanorods, nanostars, and nanoprisms, using simple chemical methods and compared their bulk refractive index sensitivities (RIS). The sensitivity of nanoparticles increases with the size of nanoparticles, and a maximum sensitivity in gold nanoprisms was observed. The comparison of bulk RIS of different sizes and shapes of gold nanoparticles helps in selecting the most suitable nanoparticle to achieve high sensitivity in LSPR-based sensing.
... The synthesis of AuNTs was made by following the seed-mediated growth method, described and optimized by several research groups (Scheme 1a) [35,36]. Briefly, we obtain the nanoparticles from the reduction of HAuCl 4 by Na 2 S 2 O 3 in an aqueous media. ...
Electrochemical biosensors are widely used in a multitude of applications, such as medical, nutrition, research, among other fields. These sensors have been historically used and have not undergone many changes in terms of the involved electrochemical processes. In this work, we propose a new approach on the immobilization and enhancement of the electrochemical properties of the sensing layers through the control and bioconjugation of hemoproteins (hemoglobin, myoglobin, and cytochrome C) on anisotropic gold nanoparticles (gold nanotriangles (AuNTs)). The hemeproteins and the AuNTs are mixed in a solution, resulting in stable bioconjugates that are deposited onto the electrode surface to obtain the biosensors. All the systems proposed herein exhibited direct well-defined redox responses, highlighting the key role of the AuNTs acting as mediators of such electron transfers. Several protein layers surrounding the AuNTs are electroactive, as demonstrated from the charge measured by cyclic voltammetry. The retention of the stability of the hemeproteins once they are part of the bioconjugates is evidenced towards the electrocatalytic reduction of hydrogen peroxide, oxygen, and nitrite. The parameters obtained for the proposed biosensors are similar or even lower than those previously reported for similar systems based on nanomaterials, and they exhibit attractive properties that make them potential candidates for the latest developments in the field of sensing devices.
... In addition to the HIV-1 reverse transcriptase, the HIV-1 protease is a critical component of the HIV replication cycle at the post-entry stage. HIV-1 protease is a retroviral aspartyl protease (retropepsin), an enzyme involved with peptide bond hydrolysis in retroviruses [84]. In HIV, protease shepherds viral components to the host cell membrane, causing immature virions to emerge, which menacingly infect other cells. ...
Background The adoption of Antiretroviral Therapy (ART) substantially extends the life expectancy and quality of HIV-infected patients. Yet, eliminating the latent reservoirs of HIV to achieve a cure remains an unmet need. The advent of nanomedicine has revolutionized the treatment of HIV/AIDS. The present study explores a unique combination
of Tenofovir (TNF) with gold nanoparticles (AuNPs) as a potential therapeutic approach to overcome several
limitations of the current ART.
Results TNF-tethered AuNPs were successfully synthesized. Cell viability, genotoxicity, haemolysis, and histopathological studies confirmed the complete safety of the preparation. Most importantly, its anti-HIV1 reverse transcriptase
activity was ~ 15 folds higher than the native TNF. In addition, it exhibited potent anti-HIV1 protease activity, a much sought-after target in anti-HIV1 therapeutics. Finally, the in vivo biodistribution studies validated that the AuNPs could reach many tissues/organs, serving as a secure nest for HIV and overcoming the problem of deficient drug delivery to
HIV reservoirs.
Conclusions We show that the combination of TNF and AuNPs exhibits multifunctional activity, viz. anti-HIV1 and anti-HIV1 protease. These findings are being reported for the first time and highlight the prospects of developing AuNP-TNF as a novel next-generation platform to treat HIV/AIDS.
... While synthesis of gold nanoparticles various chemical compounds are used to avert agglomeration such as surfactants, organic/inorganic molecules, polymers. These compounds served as capping agents and provide structural stability to gold nanoparticles [6,7]. Curcumin is one of the natural organic molecules widely used in nanotherapeutics as well as reducing and capping agent for preparation of gold nanoparticles [8]. ...
A solvent casting technique was used for the preparation of biomimetic nanocomposites scaffolds at three various concentrations of Curcumin loaded gold nanoparticles (Cur-AuNPs-1, 1.5, and 2 ml) as filler materials with chitosan-sodium alginate composite. The physico-chemical properties of prepared Cu-Au NPs and biomimetic nanocomposites were analyzed using various characterization techniques. In vitro biocompatibility of biomimetic nanocomposites are determined using simulated body fluid for biomineralization property, HAp formation and phosphate buffer saline (PBS) for swelling property, protein adsorption. Antibacterial activity of Cur-Au NPs and their nanocomposites carried out against Escherichia coli (E. coli) and Staphylococcus aureus. In vitro cytotoxicity of Cur-AuNPs is identified against UC-6 and MDA-MB 231 cell lines. The use of above studies and activity of Cur-AuNPs with contain biomimetic nanocomposites can adoptable for nanotheranostics.
... Nanomaterials with these unique features were used to address several problems in many scientific areas and industry, including the food industry. Along with these advanced features, nanotechnology became one of the most promising technologies in the 21st century [94][95][96][97][98][99][100]. ...
Throughout the food supply chain, including production, storage, and distribution, food can be contaminated by harmful chemicals and microorganisms, resulting in a severe threat to human health. In recent years, the rapid advancement and development of nanotechnology proposed revolutionary solutions to solve several problems in scientific and industrial areas, including food monitoring. Nanotechnology can be incorporated into chemical and biological sensors to improve analytical performance, such as response time, sensitivity, selectivity, reliability, and accuracy. Based on the characteristics of the contaminants and the detection methods, nanotechnology can be applied in different ways in order to improve conventional techniques. Nanomaterials such as nanoparticles, nanorods, nanosheets, nanocomposites, nanotubes, and nanowires provide various functions for the immobilization and labeling of contaminants in electrochemical and optical detection. This review summarizes the recent advances in nanotechnology for detecting chemical and biological contaminations in the food supply chain.
... The AuNPs are crystalline in nature, as evidenced by the distinct lattices. The diffraction pattern derived from AuNPs is depicted in Fig. S1d, with rings corresponding to the (1 1 1), (2 0 0), (3 1 1), and (2 2 2) reflections of gold's face-centered cubic (fcc) structure [47]. HRTEM scans of B-GQDs notify modest particle sizes ranging from 2 to 6 nm that are densely and consistently scattered (See Fig. S2(a-b)). ...
To acquire substantial electrochemical signals of guanine-GUA and adenine-ADE present in deoxyribonucleic acid-DNA, it is critical to investigate innovative electrode materials and their interfaces. In this study, gold-loaded boron-doped graphene quantum dots ([email protected]) interface was prepared via ultrasound-aided reduction method for monitoring GUA and ADE electrochemically. Transmission electron microscopy-TEM, Ultraviolet-Visible spectroscopy-UV-Vis, Raman spectroscopy, X-ray photoelectron spectroscopy-XPS, cyclic voltammetry-CV, and differential pulse voltammetry-DPV were used to examine the microstructure of the fabricated interface and demonstrate its electrochemical characteristics. The sensor was constructed by depositing the as-prepared [email protected] as a thin layer on a glassy carbon-GC electrode by the drop-casting method and carried out the electrochemical studies. The resulting sensor exhibited a good response with a wide linear range (GUA= 0.5-20 μM, ADE= 0.1-20 μM), a low detection limit-LOD (GUA= 1.71 μM, ADE=1.84 μM), excellent sensitivity (GUA= 0.0820 µAµM⁻¹, ADE=0.1561 µAµM⁻¹) and selectivity with common interferents results from biological matrixes. Furthermore, it seems to have prominent selectivity, reproducibility, repeatability, and long-lasting stability. The results demonstrate that the fabricated [email protected]/GC electrode is a simple and effective sensing platform for detecting GUA and ADE in neutral media at low potential as it exhibited prominent synergistic impact and outstanding electrocatalytic activity corresponding to individual AuNPs and B-GQDs modified electrodes.
... The synthesized Ag NPs are dispersed and have spheroidal morphologies. The observed diffuse bands in the SAED patterns can be indexed to the (111), (200), (220), and (311) diffraction planes of Ag, which helps determine the phase of the NPs [33]. No Figure 3b shows the UV spectra of the Ag NP solutions obtained at different ultrasonic times (40,80, and 120 min) at a frequency of 100 kHz. ...
... The synthesized Ag NPs are dispersed and have spheroidal morphologies. The observed diffuse bands in the SAED patterns can be indexed to the (111), (200), (220), and (311) diffraction planes of Ag, which helps determine the phase of the NPs [33]. No discernible differences were observed on changing the ultrasonic parameters, indicating that the frequency and ultrasonic time had no major effect on the crystallinity of the produced Ag NPs. ...
Polyvinylpyrrolidone (PVP) is used in a wide variety of applications because of its unique chemical and physical features, including its biocompatibility and low toxicity. In this study, hollow PVP/silver nanoparticle (PVP/Ag NP) composite fibers were synthesized. Stable, spherical Ag NPs, with an average size of 14.4 nm, were produced through a facile sonochemical reduction method. A small amount of starch as a potent reducing and stabilizing agent was used during the reduction of Ag ions to Ag NPs. The fabricated Ag NPs were then added to a 10 wt% PVP-dichloromethane (DCM) solution, which was utilized as an electrospinning feed solution under a dense carbon dioxide (CO2) environment at 313 K and 5 MPa and an applied voltage of 15 kV. The dense CO2 enabled rapid extraction of DCM from the PVP-Ag NPs-DCM solution, which was then dissolved into PVP/Ag NPs, resulting in a hollow structure. Scanning electron microscopy, Fourier-transform infrared (FT-iR) spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses, and thermogravimetric analysis (TGA), were used to characterize the electrospinning products.
... 21,49 There are a number of reports in literature that show transitions of crystallinity in gold. 13,52 Here, we have chosen a ligand system for which changes in crystallinity are well known and documented, to enable us to identify the incorporation of different types of twin planes. 53 Growth under these ligand conditions is known to lead to either single-crystal products or penta-twinned crystals. ...
... Initially, sodium thiosulfate solution was combined with HAuCl 4 solution, and after 9 min of stirring, sodium thiosulfate solution was further added. 146 With an increase in sodium thiosulfate volume added in the second step, larger gold nanoplates were obtained. Stability and tunability of gold nanoplates obtained by this method have been further studied, and it is found that the stable nanoplates are formed only in a certain range of the HAuCl 4 /Na 2 S 2 O 3 molar ratio. ...
Due to their unique optical properties, anisotropic silver and gold nanostructures are widely studied for applications ranging from catalysis to sensing and imaging. The wet chemical synthesis method provides a convenient route to produce desired nanostructures with good control over the morphology of nanoparticles. Nanostructures prepared in the solutions can be loaded on the substrate to fabricate cost-effective nanoplasmonic substrates at a large scale. This review discusses the various strategies available to synthesize anisotropic silver and gold nanostructures by wet chemical methods. The applications of these nanostructures are also presented, particularly in the context of localized surface plasmon resonance-based refractometric sensing.
... [6,[8][9][10] Nevertheless significant attempts are now being made to improve therapeutic and diagnostic properties in a single effective nanomedicine solution: this concept, coined as "theranostics," comprises selective nanosystems that are able to diagnose, deliver, and monitor the therapeutic response. [11][12][13][14] Gold nanoparticles (AuNPs), due to their innate bioinertness, quantum-size-related properties, such as highly tunable optical properties (e.g., plasmonically resonant optical absorbance and fluorescence or Raman scattering enhancement), [15] have shown remarkable promise in cancer diagnostics and treatment. Indeed, as intrinsic theranostic agents, AuNPs stand out because of their remotely activatable anticancer activity (photothermal ablation) [16,17] and optical or hybrid imaging features (photoacoustic imaging, PAI), [18] which removes the need of other nanocarriers to rely on additional therapeutic and diagnostic agents. ...
Near infrared (NIR)‐resonant gold nanoparticles (AuNPs) hold great promise in cancer diagnostics and treatment. However, translating the theranostic potential of AuNPs into clinical applications still remains a challenge due to the difficulty to improve the efficiency and specificity of tumor delivery in vivo as well as the clearance from liver and spleen to avoid off target toxicity. In this study, endothelial colony forming cells (ECFCs) are exploited as vehicles to deliver AuNPs to tumors. It is first demonstrated that ECFCs display a great capability to intake AuNPs without losing viability, and exert antitumor activity per se. Using a human melanoma xenograft mouse model, it is next demonstrated that AuNP‐loaded ECFCs retain their capacity to migrate to tumor sites in vivo 1 day after injection and stay in the tumor mass for more than 1 week. In addition, it is demonstrated that ECFC‐loaded AuNPs are efficiently cleared by the liver over time and do not elicit any sign of damage to healthy tissue.
