The role of incorporation of gold nanoparticles (50-130 nm in diameter) into a series of photocurable methacrylic-acrylic based biosensor membranes containing tyrosinase on the response for phenol detection was investigated. Membranes with different hydrophilicities were prepared from 2-hydroxyethyl methacrylate and n-butyl acrylate via direct photocuring. A range of gold nanoparticles concentrations from 0.01 to 0.5 % (w/w) was incorporated into these membranes during the photocuring process. The addition of gold nanoparticles to the biosensor membrane led to improvement in the response time by a reduction of approximately 5 folds to give response times of 5-10 s. The linear response range of the phenol biosensor was also extended from 24 to 90 mM of phenol. The hydrophilicities of the membrane matrices demonstrated strong influence on the biosensor response and appeared to control the effect of the gold nanoparticles. For less hydrophilic methacrylic-acrylic membranes, the addition of gold nanoparticles led to a poorer sensitivity and detection limit of the biosensor towards phenol. Therefore, for the application of gold nanoparticles in the enhancement of a phenol biosensor response, the nanoparticles should be immobilized in a hydrophilic matrix rather than a hydrophobic material.
T4 genotype Acanthamoeba are opportunistic pathogens that cause two types of infections, including vision-threatening Acanthamoeba keratitis (AK) and a fatal brain infection known as granulomatous amoebic encephalitis (GAE). Due to the existence of ineffective treatments against Acanthamoeba, it has become a potential threat to all contact lens users and immunocompromised patients. Metal nanoparticles have been proven to have various antimicrobial properties against bacteria, fungi, and parasites. Previously, different types of cobalt nanoparticles showed some promise as anti-acanthamoebic agents. In this study, the objectives were to synthesize and characterize the size, morphology, and crystalline structure of cobalt phosphate nanoparticles, as well as to determine the effects of different sizes of cobalt metal-based nanoparticles against A. castellanii. Cobalt phosphate octahydrate (CHP), Co3(PO4)2•8H2O, was synthesized by ultrasonication using a horn sonicator, then three different sizes of cobalt phosphates Co3(PO4)2 were produced through calcination of Co3(PO4)2•8H2O at 200 °C, 400 °C and 600 °C (CP2, CP4, CP6). These three types of cobalt phosphate nanoparticles were characterized using a field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analysis. Next, the synthesized nanoparticles were subjected to biological assays to investigate their amoebicidal, amoebistatic, anti-encystation, and anti-excystation effects against A. castellanii, as well as cell cytotoxicity. The overall results showed that 1.30 ± 0.70 µm of CHP microflakes demonstrated the best anti-acanthemoebic effects at 100 µg/mL, followed by 612.50 ± 165.94 nm large CP6 nanograins. However, amongst the three tested cobalt phosphates, Co3(PO4)2, the smaller nanoparticles had stronger antiamoebic effects against A. castellanii. During cell cytotoxicity analysis, CHP exhibited only 15% cytotoxicity against HeLa cells, whereas CP6 caused 46% (the highest) cell cytotoxicity at the highest concentration, respectively. Moreover, the composition and morphology of nanoparticles is suggested to be important in determining their anti-acathamoebic effects. However, the molecular mechanisms of cobalt phosphate nanoparticles are still unidentified. Nevertheless, the results suggested that cobalt phosphate nanoparticles hold potential for development of nanodrugs against Acanthamoeba.
Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20V anodizing time: 30min to 3h) are used for anodizing porous titanium structures that were later heat treated at 500°C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500°C improve the cell culture response of porous titanium.
Matched MeSH terms: Metal Nanoparticles/administration & dosage; Metal Nanoparticles/ultrastructure; Metal Nanoparticles/chemistry
Silver-reduced graphene oxide (Ag-rGO) nanohybrid was synthesized by applying a slight modification to the Turkevich method using trisodium citrate as a reducing and stabilizing agent to catalyze the non-enzymatic electrochemical detection of hydrogen peroxide (H₂O₂). Spherical silver nanoparticles (AgNPs) with an average particle size of 2.2 nm surfaced on reduced graphene oxide (rGO) sheets. Cyclic voltammograms (CV) obtained from glassy carbon (GC) electrode coated with Ag-rGO nanohybrid (4 mM) exhibited a peak at an overpotential of -0.52 V, with a larger faradaic current for the reduction of H₂O₂. Using the modified electrode for the linear sweep voltammetry (LSV) detection of H₂O₂, the detection limit and sensitivity were determined to be 4.8 μM (S/N ═ 3) and 0.0262 μA μM-1, respectively. The sensor appeared selective and stable towards H₂O₂ in the presence of possible interference, and it also demonstrated good recoveries of H₂O₂ concentration in real water samples.
Vibrio cholerae is a Gram-negative bacterium that causes cholera, a diarrheal disease. Cholera is widespread in poor, under-developed or disaster-hit countries that have poor water sanitation. Hence, a rapid detection method for V. cholerae in the field under these resource-limited settings is required. In this paper, we describe the development of an electrochemical genosensor assay using lyophilized gold nanoparticles/latex microsphere (AuNPs-PSA) reporter label. The reporter label mixture was prepared by lyophilization of AuNPs-PSA-avidin conjugate with different types of stabilizers. The best stabilizer was 5% sorbitol, which was able to preserve the dried conjugate for up to 30 days. Three methods of DNA hybridization were compared and the one-step sandwich hybridization method was chosen as it was fastest and highly specific. The performance of the assay using the lyophilized reagents was comparable to the wet form for detection of 1aM to 1fM of linear target DNA. The assay was highly specific for V. cholerae, with a detection limit of 1fM of PCR products. The ability of the sensor is to detect LAMP products as low as 50ngµl(-1). The novel lyophilized AuNPs-PSA-avidin reporter label with electrochemical genosensor detection could facilitate the rapid on-site detection of V. cholerae.
Matched MeSH terms: Metal Nanoparticles/chemistry*
C-reactive protein (CRP) is an acute phase reactant to be a marker of inflammation and has been correlated with the cardiac injury. An immunoassay was performed using anti-human CRP antibody on an InterDigitated electrode (IDE) sensor to determine and specify CRP concentration for diagnosing the condition of myocardial inflammation. To promote the detection, gold nanoparticle (GNP) was seeded on the aminated-IDE surface. Anti-CRP was hitched on the GNP-seeded surface and identified the abundance of CRP. The limit of quantification was found as 100 fM, and the higher current response was noticed by increasing CRP concentrations with the sensitivity at 1 pM. Furthermore, CRP-spiked human serum did not interfere the determination of CRP and increased the current response, indicating suitability for a real-life sample. Similarly, the control experiments with nonimmune antibody Troponin I are not showing the definite current responses, proving the selective identification of CRP. This method of diagnosing is needful to determine the cardiovascular injury at the right time.
Matched MeSH terms: Metal Nanoparticles/chemistry*
This study presents the electromagnetic (EM) characterization of a multiwalled carbon nanotubes (MWCNT)-silver nanoparticles (AgNP)-reinforced poly(vinyl alcohol) (PVA) hybrid nanocomposite fabricated via the solution mixing technique. Primarily, the structure and morphological properties of the PVA/MWCNT-AgNP hybrid nanocomposite are confirmed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The complex permittivity (ε*) and permeability (μ*), as well as the electromagnetic scattering parameters are measured using a PNA network analyzer equipped with X-band waveguide. The results showed an enhanced permittivity (ε' ≈ 25) value of the hybrid nanocomposite in the frequency range of 8-12 GHz. However, the permeability decreased to almost zero (μ' ≈ 0.4) since the inclusion of AgNP with an average particle size of 40 nm is not susceptible to magnetization and causes higher magnetic losses (tan δμ) than dielectric losses (tan δε). Remarkably, the hybrid nanocomposite reduced transmission of electromagnetic (EM) wave by nearly 60% in comparison to PVA/MWCNT. This is attributed to the enhanced absorption and reflection at the nanotubes, and metal-dielectric interfaces have induced multiple internal reflections owing to the porous structure of the nanocomposite. The prospect of the PVA/MWCNT-AgNP hybrid nanocomposite is favorable as a thin absorbing material for EM shielding applications.
In the present study, a nanocomposite of f-MWCNTs-chitosan-Co was prepared by the immobilization of Co(II) on f-MWCNTs-chitosan by a self-assembly method and used for the quantitative determination of paracetamol (PR). The composite was characterized by field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analysis (EDX). The electroactivity of cobalt immobilized on f-MWCNTs-chitosan was assessed during the electro-oxidation of paracetamol. The prepared GCE modified f-MWCNTs/CTS-Co showed strong electrocatalytic activity towards the oxidation of PR. The electrochemical performances were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Under favorable experimental conditions, differential pulse voltammetry showed a linear dynamic range between 0.1 and 400 μmol L-1 with a detection limit of 0.01 μmol L-1 for the PR solution. The fabricated sensor exhibited significant selectivity towards PR detection. The fabricated sensor was successfully applied for the determination of PR in commercial tablets and human serum sample.
Matched MeSH terms: Metal Nanoparticles/ultrastructure; Metal Nanoparticles/chemistry
Titanium dioxide (TiO2) nanoparticles (NPs) have been doped with varying amounts (0.005, 0.010 and 0.015 M) of silver nanoparticles (Ag NPs) using hydrothermal method. Further, in this work, a green approach was followed for the formation of Ag@TiO2 NPs using Aloe vera gel as a capping and reducing agent. The structural property confirmed the presence of anatase phase TiO2. Increased peak intensity was observed while increasing the Ag concentration. Further, the morphological and optical properties have been studied, which confirmed the effective photocatalytic behavior of the prepared Ag@TiO2 NPs. The photocatalytic performance of Ag@TiO2 has been considered for the degradation of picric acid in the visible light region. The concentration at 0.010 M of the prepared Ag@TiO2 has achieved higher photocatalytic performance within 50 min, which could be attributed to its morphological behavior. Similarly, anticancer activity against lung cancer cell lines (A549) was also determined. The Ag@TiO2 NPs generated a large quantity of reactive oxygen species (ROS), resulting in complete cancer cell growth suppression after their systemic in vitro administration. Ag@TiO2 NPs was adsorbed visible light that leads to an enhanced anticancer sensitivity by killing and inhibiting cancer cell reproduction through cell viability assay test. It was clear that 0.015 M of Ag@TiO2 NPs were highly effective against human lung cancer cell lines and showed increased production of ROS in cancer cell lines due to the medicinal behavior of the Aloe vera gel.
Matched MeSH terms: Metal Nanoparticles/toxicity; Metal Nanoparticles/chemistry*
Nanomaterials can be incorporated in the synthesis of membrane to obtain mixed-matrix membrane with marked improvement in properties and performance. However, stability and dispersion of the nanomaterials in the membrane matrix, as well as the need to use high ratio of nanomaterials for obvious improvement of membrane properties, remain a major hurdle for commercialization. Hence, this study aims to investigate the improvement of polyamide 6,6 membrane properties with the incorporation of silver nanoparticles decorated on graphene oxide (Ag-GO) nanoplates and at the same time focus is given to the issues above. Graphene oxide nanoplates were synthesized using the modified Hummers' method and decorated with silver before embedded into the polyamide 6,6 matrix. Physicochemical characterizations were conducted on both nanoplates and the mixed-matrix Ag-GO polyamide 6,6 membrane. The issues of Ag agglomeration and leaching were not observed, which could be attributed to the decoration of Ag on GO that helped to disperse the nanomaterials and provided a better anchor point for the attachment of Ag nanoparticles. The synthesized membrane showed marked improvement regarding flux (135% increment) and antifouling (40% lower irreversible fouling), which could be ascribed to the more negative charge of membrane surface (-14 ± 6 to -31 ± 3.8 mV) and hydrophilicity (46% enhancement) of the membranes. With minimal embedment of Ag nanoparticles, the membrane showed superior antibacterial property where the E. coli bacteria could not form a single colony on the membrane surface. Overall, the decoration of Ag on GO nanoplates could be a promising approach to resolve the agglomeration and leaching issues as well as reduce the amount of precious Ag in the synthesis of Ag-GO polyamide 6,6 membrane.
This study investigated the different thicknesses of TiO2 photoanode films and the effect of surface plasmon resonance (SPR) of Ag-TiO2 nanocomposites on the current-voltage (I-V) performance of dye-sensitized solar cells (DSSC). The TiO2 layer was deposited using the doctor blade technique and the thickness of the TiO2 films was controlled by using a different number of Scotch tape layers. The silver nanoparticles (AgNP) were synthesised using a chemical reduction method and the concentration of sodium citrate as a reducing agent was varied from 4 to 12 mM to study the effect of citrate ion on the size of the nanoparticles. Ag-TiO2 nanopowder was prepared by adding pure anatase TiO2 powder into AgNP colloidal solution. The mixture was left to dry for 24 h to obtain Ag-TiO2 powder for paste preparation. The three-layer Scotch tape, with thickness of 14.38 µm, achieved a high efficiency of 4.14%. This results showed that three layers was the optimal thickness to improve dye loading and to reduce the charge recombination rate. As for the Ag-TiO2 nanocomposites, 10 mM of AgNP, with a mean diameter of 65.23 nm and high efficiency of 6.92%, proved that SPR can enhance the absorption capability of dye and improve the photon-to-electron generation.
This study demonstrated the terminated sialo-sugar chains (Neu5Acα2,6Gal and Neu5Acα2,3Gal) mediated specificity enhancement of influenza virus and chicken red blood cell (RBC) by hemagglutination assay. These glycan chains were immobilized on the gold nanoparticle (GNP) to withhold the higher numbers. With the preliminary optimization, a clear button formation with 0.5% RBC was visualized. On the other hand, intact B/Tokio/53/99 with 750 nM hemagglutinin (HA) displayed a nice hemagglutination. The interference on the specificity of RBC and influenza virus was observed by anti-influenza aptamer at the concentration 31 nM, however, there is no hemagglutination prevention was noticed in the presence of complementary aptamer sequences. Spiking GNP conjugated Neu5Acα2,6Gal or Neu5Acα2,3Gal or a mixture of these two to the reaction promoted the hemagglutination to 63 folds higher with 12 nM virus, whereas under the same condition the heat inactivated viruses were lost the hemagglutination. Neuraminidases from Clostridium perfringens and Arthrobacter ureafaciens at 0.0025 neuraminidase units are able to abolish the hemagglutination. Other enzymes, Glycopeptidase F (Elizabethkingia meningoseptica) and Endoglycosidase H (Streptomyces plicatus) did not show the changes with agglutination. Obviously, sialyl-Gal-terminated glycan conjugated GNP amendment has enhanced the specificity of erythrocyte-influenza virus and able to be controlled by aptamer or neuraminidases. This article is protected by copyright. All rights reserved.
This work presents a simple green synthesis of gold nanoparticles (AuNPs) by using an aqueous extract of Etlingera elatior (torch ginger). The metabolites present in E. elatior, including sugars, proteins, polyphenols, and flavonoids, were known to play important roles in reducing metal ions and supporting the subsequent stability of nanoparticles. The present work aimed to investigate the ability of the E. elatior extract to synthesise AuNPs via the reduction of gold (III) chloride hydrate and characterise the properties of the nanoparticles produced. The antioxidant properties of the E. elatior extract were evaluated by analysing the total phenolic and total flavonoid contents. To ascertain the formation of AuNPs, the synthesised particles were characterised using the ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) microscopy, and dynamic light scattering (DLS) measurement. The properties of the green synthesised AuNPs were shown to be comparable to the AuNPs produced using a conventional reducing agent, sodium citrate. The UV-Vis measured the surface plasmon resonance of the AuNPs, and a band centered at 529 nm was obtained. The FTIR results proved that the extract contained the O-H functional group that is responsible for capping the nanoparticles. The HRTEM images showed that the green synthesized AuNPs were of various shapes and the average of the nanoparticles' hydrodynamic diameter was 31.5 ± 0.5 nm. Meanwhile, the zeta potential of -32.0 ± 0.4 mV indicates the high stability and negative charge of the AuNPs. We further successfully demonstrated that using the green synthesised AuNPs as the nanocomposite to modify the working surface of screen-printed carbon electrode (SPCE/Cs/AuNPs) enhanced the rate of electron transfer and provided a sensitive platform for the detection of Cu(II) ions.
Matched MeSH terms: Metal Nanoparticles/ultrastructure; Metal Nanoparticles/chemistry*
Biosynthesis of nanoparticles has now become a novel trend in addressing some of the environmental issues by adopting eco-friendly approaches in manoeuvring nanoparticles for various applications. Plants and micro-organisms have been the potential sources of the biological mode of synthesizing nanoparticles as part of their bioremediation process. This principle has been harnessed for synthesizing nanoparticles either extra or intracellularly. In this line of phyto-mediated synthesis, eucalyptus buds have been used for synthesizing gold nanoparticles (Au NPs) under optimized laboratory conditions. The UV-visible spectrum of the Au NPs showed typical surface plasmon resonance at 550 nm (λmax) with a crystalline phase measuring <100 nm in size and monodispersed as revealed from XRD, FESEM, and AFM analyses. The biological role of phytochemical concoction in reducing and stabilizing the Au NPs was clearly identified from FT-IR studies. The antimicrobial effect of the Au NPs against clinically important pathogens viz. Staphylococcus sp., Pseudomonas sp., Bacillus sp. and E. coli determined using the disk diffusion method showed no significant antibacterial effect at all concentrations. Cytotoxicity studies were carried using Vero and HEp-2 cell lines and the 50% inhibition concentration (IC50) was determined to be 1.25 mg and 0.625 mg/mL respectively. Au NPs with potential antimicrobial and anti-proliferative effects could found profound implications in the field of nanomedicine once the toxicity in vivo has been investigated.
Cockle shell-derived calcium carbonate nanoparticles have shown promising potentials as slow drug-releasing compounds in cancer chemotherapy. In this study, we evaluated the in vitro efficacy of docetaxel (DTX)-loaded CaCO3NP on 4T1 cell line. This was achieved by evaluating the following: cytotoxicity using MTT assay, fluorescence imaging, apoptosis with Annexin V assay, cell cycle analysis, scanning (SEM) and transmission electron microscopy (TEM), and scratch assay. Based on the results, DTX-CaCO3NP with a DTX concentration of 0.5 μg/mL and above had comparable cytotoxic effects with free DTX at 24 h, while all concentrations had similar cytotoxic effect on 4T1 cells at 48 and 72 h. Fluorescence and apoptosis assay showed a higher (p
Matched MeSH terms: Metal Nanoparticles/administration & dosage; Metal Nanoparticles/chemistry*
Lead-halide perovskite nanoparticles (NPs) are a new technology, and investigation of toxicity is of considerable importance due to the potential lead (Pb) release into the environment. The aim of the study was to investigate aqueous and dietary toxicity of Pb-halide perovskite NP and Pb in zebrafish Danio rerio. Perovskite NP toxicity was evaluated in zebrafish by mortality, gene expression, histopathology, and phylogenetic analysis of gut microbiota. Zebrafish larvae were exposed to five Pb-halide perovskite NPs in parallel with Pb(NO3)2 exposures, and zebrafish adults were exposed to the three perovskite NPs that caused the strongest effect and Pb(NO3)2. No median lethal concentration (LC50) was observed for zebrafish larvae exposed to up to 200 mg/L of perovskite NPs for 96 h. Mortality, metallothionein 2 (mt2) and δ-aminolevulinic acid dehydratase (ala-d) gene expression (24-h exposure) in zebrafish larvae after aqueous perovskite NPs exposures did not differ from total Pb concentration - response curves. The lack of differences in mortality and gene expression between perovskite NPs and soluble Pb after aqueous exposure suggest that toxicity from perovskite NPs can be attributed to bioavailable Pb rather than nano-specific effects. Induction of mt2 and reduction of ala-d expression levels in liver tissues showed Pb bioavailability after 2-d and 4-d dietary exposure to perovskite-spiked feeds. Changes in gut microbiota of adult zebrafish were detected after 14-d exposure to Pb-spiked food, but no changes were detected from perovskite-NP spiked food. The phylogenetic analysis identified different microbiome profiles of Pb-fed fish compared to perovskite-fed fish suggesting a different mechanism of toxicity. Exposure to Pb-halide perovskite NPs led to absorption of Pb likely from release of Pb ions rather than absorption of NPs. Pb-halide perovskite NPs can release bioavailable Pb and this needs to be considered during the development of this technology.
Here we examine the organ level toxicology of both carbon black (CB) and silver nanoparticles (AgNP). We aim to determine metal-specific effects to respiratory function, inflammation and potential interactions with lung lining fluid (LLF). C57Bl6/J male mice were intratracheally instilled with saline (control), low (0.05 μg/g) or high (0.5 μg/g) doses of either AgNP or CB 15 nm nanospheres. Lung histology, cytology, surfactant composition and function, inflammatory gene expression, and pulmonary function were measured at 1, 3, and 7 days post-exposure. Acutely, high dose CB resulted in an inflammatory response, increased neutrophilia and cytokine production, without alteration in surfactant composition or respiratory mechanics. Low dose CB had no effect. Neither low nor high dose AgNPs resulted in an acute inflammatory response, but there was an increase in work of breathing. Three days post-exposure with CB, a persistent neutrophilia was noted. High dose AgNP resulted in an elevated number of macrophages and invasion of lymphocytes. Additionally, AgNP treated mice displayed increased expression of IL1B, IL6, CCL2, and IL10. However, there were no significant changes in respiratory mechanics. At day 7, inflammation had resolved in AgNP-treated mice, but tissue stiffness and resistance were significantly decreased, which was accompanied by an increase in surfactant protein D (SP-D) content. These data demonstrate that the presence of metal alters the response of the lung to nanoparticle exposure. AgNP-surfactant interactions may alter respiratory function and result in a delayed immune response, potentially due to modified airway epithelial cell function.
Many wounds are unresponsive to currently available treatment techniques and therefore there is an immense need to explore suitable materials, including biomaterials, which could be considered as the crucial factor to accelerate the healing cascade. In this study, we fabricated polyhydroxyalkanoate-based antibacterial mats via an electrospinning technique. One-pot green synthesized graphene-decorated silver nanoparticles (GAg) were incorporated into the fibres of poly-3 hydroxybutarate-co-12 mol.% hydroxyhexanoate (P3HB-co-12 mol.% HHx), a co-polymer of the polyhydroxyalkanoate (PHA) family which is highly biocompatible, biodegradable, and flexible in nature. The synthesized PHA/GAg biomaterial has been characterized by field emission scanning electron microscopy (FESEM), elemental mapping, thermogravimetric analysis (TGA), UV-visible spectroscopy (UV-vis), and Fourier transform infrared spectroscopy (FTIR). An in vitro antibacterial analysis was performed to investigate the efficacy of PHA/GAg against gram-positive Staphylococcus aureus (S. aureus) strain 12,600 ATCC and gram-negative Escherichia coli (E. coli) strain 8739 ATCC. The results indicated that the PHA/GAg demonstrated significant reduction of S. aureus and E. coli as compared to bare PHA or PHA- reduced graphene oxide (rGO) in 2 h of time. The p value (p < 0.05) was obtained by using a two-sample t-test distribution.
Silver nanoparticles (Ag-NPs) were successfully synthesized using the UV irradiation of aqueous solutions containing AgNO(3) and gelatin as a silver source and stabilizer, respectively. The UV irradiation times influence the particles' diameter of the Ag-NPs, as evidenced from surface plasmon resonance (SPR) bands and transmission electron microscopy (TEM) images. When the UV irradiation time was increased, the mean size of particles continuously decreased as a result of photoinduced Ag-NPs fragmentation. Based on X-ray diffraction (XRD), the UV-irradiated Ag-NPs were a face-centered cubic (fcc) single crystal without any impurity. This study reveals that the UV irradiation-mediated method is a green chemistry and promising route for the synthesis of stable Ag-NPs for several applications (e.g., medical and surgical devices). The important advantages of this method are that it is cheap, easy, and free of toxic materials.
Matched MeSH terms: Metal Nanoparticles/ultrastructure; Metal Nanoparticles/chemistry*
In this study, an electrochemical sensor was fabricated based on gold nanoparticles/ ethylenediamine/ multi-wall carbon-nanotubes modified gold electrode (AuNPs/en/MWCNTs/AuE) for determination of valrubicin in biological samples. Valrubicin was effectively accumulated on the surface of AuNPs/en/MWCNTs/AuE and produced a pair of redox peaks at around 0.662 and 0.578V (vs. Ag/AgCl) in citrate buffer (pH4.0). The electrochemical parameters including pH, buffer, ionic strength, scan rate and size of AuNPs have been optimized. There was a good linear correlation between cathodic peak current and concentration of valrubicin in the range of 0.5 to 80.0μmolL(-1) with the detection limit of 0.018μmolL(-1) in citrate buffer (pH4.0) and 0.1molL(-1) KCl. Finally, the constructed sensor was successfully applied for determination of valrubicin in human urine and blood serum. In further studies, the different sequences of single stranded DNA probes have been immobilized on the surface of AuNPs decorated on MWCNTs to study the interaction of oligonucleotides with valrubicin.
Matched MeSH terms: Metal Nanoparticles/chemistry*