Presence Of Silver Nanoparticles Research Articles

Determination of Norfloxacin by Sensitized Terbium Fluorescence in the Presence of Silver Nanoparticles and Surfactant Micelles

Determination of Norfloxacin by Sensitized Terbium Fluorescence in the Presence of Silver Nanoparticles and Surfactant Micelles

Evaluation of PVC@Silver Nanocomposite as Sensor for Low Limit Detection of Cadmium Ion By Surface Plasmon Resonance Based Method

AbstractThis study explores the development of a PVC@Silver nanocomposite for enhanced detection of cadmium ions in water samples. Various characterization techniques confirmed the successful incorporation of silver nanoparticles into the polyvinyl chloride (PVC) matrix across different concentrations (1–4%). X-ray diffraction revealed the face-centered cubic crystalline structure of the silver nanoparticles, with the intensities of the (111), (200), (220), and (311) peaks increasing with higher Ag concentrations. The average crystallite sizes ranged from 26.1 nm (3% Ag) to 30.0 nm (2% Ag). Dynamic light scattering showed nanoparticle sizes of 24–43 nm, while zeta potential values of -24 to -40 mV indicated reasonable colloidal stability. Brunauer–Emmett–Teller (BET) surface area analysis demonstrated a decreasing surface area from 30.09 m2/g (1% Ag) to 25.27 m2/g (3% Ag), attributed to pore filling by silver nanostructures. Significantly, the PVC@Silver nanocomposite facilitated sensitive detection of Cd(II) ions using surface plasmon resonance (SPR), exhibiting an SPR angle shift of 26.30° with intensity values ranging from 10.80 (4% Ag) to 12.19 (3% Ag). UV–vis spectra revealed a prominent surface plasmon resonance band at 420–430 nm, indicating the presence of silver nanoparticles. The optical band gap varied from 4.51eV (1% Ag) to 4.12eV (4% Ag).

An Efficient Photocatalytic Oxygen Evolution System with the Coupling of Polyoxometalates with Bismuth Vanadate

In this work, a coupling system consisting of bismuth vanadate (BiVO4) and cobalt-based polyoxometalates (Co-POMs) was developed to enhance the oxygen evolution reaction. Crystallization-driven self-assembly and the wet chemical synthesis method were deployed in synthesizing Co-POMs and monoclinic–tetragonal mixed–phase BiVO4, respectively. The introduction of Co-POMs into a BiVO4-containing mixture significantly enhanced the water oxidation reaction, with a more than twofold increment in the total amount of oxygen evolved. For instance, 461.2 µmol of oxygen was evolved from the system containing 20 mg of Co-POMs compared to 195 µmol of oxygen produced from a pristine BiVO4 system. This extraordinary improvement in the oxygen evolution reaction indicates the existence of a positive synergic effect between BiVO4 and Co-POMs, in which Co-POMs could act as effective cocatalysts to extract photogenerated charge carriers generated by BiVO4 and improve the charge transfer process. However, the amount of oxygen produced was slightly reduced to 440.7 µmol with an increase in AgNO3 loading from 30 mg to 60 mg. This unforeseen phenomenon could be elucidated by the shielding effect of silver particles, in which a higher AgNO3 loading led to a more prominent shielding effect. The presence of silver nanoparticles on post-reaction BiVO4 was confirmed by TEM and XPS analysis. This newly established process scheme provides an insight into the development of an efficient photocatalytic oxygen evolution system in realizing future commercial applications toward green energy production.

Plasmonic Contact Lenses Based on Silver Nanoparticles for Blue Light Protection.

Constant exposure to blue light emanating from screens, lamps, digital devices, or other artificial sources at night can suppress melatonin secretion, potentially compromising both sleep quality and overall health. Daytime exposure to elevated levels of blue light can also lead to permanent damage to the eyes. Here, we have developed blue light protective plasmonic contact lenses (PCLs) to mitigate blue light exposure. Crafted from poly(hydroxyethyl methacrylate) (pHEMA) and infused with silver nanoparticles, these contact lenses serve as a protective barrier to filter blue light. Leveraging the plasmonic properties of silver nanoparticles, the lenses effectively filtered out the undesirable blue light (400-510 nm), demonstrating substantial protection (22-71%) while maintaining high transparency (80-96%) for the desirable light (511-780 nm). The maximum protection level reaches a peak of 79% at 455 nm, aligned with the emission peak for the blue light sourced from LEDs in consumer displays. The presence of silver nanoparticles was found to have an insignificant impact on the water content of the developed contact lenses. The lenses maintained high water retention levels within the range of 50-70 wt %, comparable to commercial contact lenses. The optical performance of the developed lenses remains unaffected in both artificial tears and contact lens storage solution over a month with no detected leakage of the nanoparticles. Additionally, the MTT assay confirmed that the lenses were biocompatible and noncytotoxic, maintaining cell viability at over 85% after 24 h of incubation. These lenses could be a potential solution to protect against the most intense wavelengths emitted by consumer displays and offer a remedy to counteract the deleterious effects of prolonged blue light exposure.

Safe and sustainable food packaging: Argemone albiflora mediated green synthesized silver-carrageenan nanocomposite films

Silver-Carrageenan (Ag/Carr) nanocomposite film for food packing application by the green method using Argemone albiflora leaf extract has been developed in this study. Different plant parts of Argemone albiflora (blue stem prickly poppy) are used all over the world for the treatment of microbial infections, jaundice, skin diseases etc. GC–MS analysis was used to examine the phytochemical found in the Argemone albiflora leaf extract which reduces the metal ions to nanoscale. The biopolymer employed in the synthesis of nanocomposite film was carrageenan, a natural carbohydrate (polysaccharide) extracted from edible red seaweeds. We developed a food packing that is biodegradable, eco-friendly, economical and free from harmful chemicals. These films possess better UV barrier and mechanical and antimicrobial properties with 1 mM AgNO3 solution. The presence of silver nanoparticles in the carrageenan matrix was evident from FESEM. The mechanical properties were analysed by a Universal testing machine (UTM) and different properties like water vapour permeability (WVP), moisture content (MC) and total soluble matter (TSM) important for food packing applications were also analysed. The antimicrobial properties of the synthesized film samples were studied against E. coli and S. aureus pathogenic bacteria. These films were employed for the storage of cottage cheese (dairy product) and strawberries (fruit). This packing increased the shelf life of the packed food effectively. Ag/Carr films are biodegradable within four weeks.

Nitrate radical formation and reaction with limonene by TiO2 photocatalysis: A kinetic study

The oxidative cleavage and the epoxidation of the endocyclic double bond of limonene can be performed in irradiated suspensions of TiO2 because of the formation of nitrate radical species deriving from the hole-induced oxidation of nitrate ions. The reaction is boosted by electron acceptors such as silver ions or in the presence of silver nanoparticles at the surface of TiO2. A thorough kinetic analysis of the reaction performances under several experimental conditions provided a set of kinetic constants, which characterise the elementary steps of this complex reaction. In particular, for the first time an evaluation of the kinetics of the formation of nitrate radicals in heterogeneous photocatalysis has been provided. Moreover, the effect of silver ions in solution and of silver nanoparticles at the surface of TiO2 could be quantitatively estimated. The developed set of kinetic equations satisfactorily predict the experimental data under several experimental conditions and can be used as the starting point of reactor design activities, in view of a future scale-up of the process. Moreover, the successful fitting of the model corroborates the proposed reaction mechanism, and provides fundamental insights on the elementary reaction steps.

Ionic and nanoparticulate silver alleviate the toxicity of inorganic mercury in marine microalga Chaetoceros muelleri.

Toxicological effects of silver nanoparticles (SNPs) in different organisms have been studied; however, interactions of SNPs with other environmental pollutants such as mercury are poorly understood. Herein, bioassay tests were performed according to ΟECD 201 guideline to assess the toxic effects induced by mercury ions (mercury chloride, MCl) on the marine microalga Chaetoceros muelleri in the presence of SNPs or silver ions (silver nitrate, SN). Acute toxicity tests displayed that the presence of SNPs or SN (0.01mg L-1) significantly reduced the toxicity of MCl (0.001, 0.01, 0.1, 1, 10, and 100mg L-1) and increased the IC50 of MCl from 0.072 ± 0.014 to 0.381 ± 0.029 and 0.676 ± 0.034mg L-1, respectively. In the presence of SN or SNPs, the mercury-reducing effect on algal population growth significantly decreased. Considering the increase of IC50, the mercury toxicity decreased approximately 5.44 and 9.66 times in the presence of SNPs or SN, respectively. The chlorophyll a and c contents decreased at all exposures; however, the decrease by MCl-SNPs and MCl-SN was significantly less than MCl except at 1mg L-1. The lowering effect of MCl-SN on chlorophyll contents was less than MCl and MCl-SNPs. MCl exposure induced significant raises in total protein content (TPC) at concentrations < 0.01mg L-1, with a maximum of ~ 70.83% attained at 100mg L-1. The effects of MCl-SNPs and MCl-SN on TPC were significantly less than MCl. Total lipid content (TLC) at all MCl concentrations was higher than the control, while at coexposure to MCl-SN, TLC did not change until 0.01mg L-1 compared with the control. The effects of MCl-SN and MCL-SNPs on TPC and TLC were in line with toxicity results, and were significantly less than those of MCl individually, confirming their antagonistic effects on MCl. The morphological changes of algal cells and mercury content of the cell wall at MCl-SN and MCl-SNPs were mitigated compared with MCl exposure. These findings highlight the mitigatory impacts of silver species on mercury toxicity, emphasizing the need for better realizing the mixture toxicity effects of pollutants in the water ecosystem.

Bio‐fabrication of silver nanoparticles using an aqueous extract of Quercus baloot: Preparation, characterization and in vitro antimicrobial evaluation

Abstract In the current study, a novel method was used to synthesize silver nanoparticles (AgNPs) by utilizing Quercus baloot aqueous extract as a reducing agent. The biosynthesized AgNPs were then subjected to various physicochemical characterizations to assess their effectiveness against microbial familiarity. The characterization techniques included ultraviolet‐visible spectro‐photometry (UV‐Vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffractometer (XRD), and Fourier‐transform infrared spectroscopy (FTIR). The UV‐Vis analysis revealed a distinctive spectral peak at 420 nm, indicating the presence of silver nanoparticles. SEM imaging displayed the nanoparticle size range of about 100 nm at a magnification of 30,000x, while TEM demonstrated that the nanoparticles had a spherical morphology with a size of approximately 100 nm. Moreover, the crystalline structure of the silver nanoparticles was confirmed by XRD analysis, further validating their successful synthesis. Additionally, FTIR analysis provided evidence of the presence of phytochemicals involved in synthesizing the AgNPs. the biosynthesized silver nanoparticles (AgNPs) were evaluated for antibacterial and antifungal activities. The AgNPs displayed substantial efficacy against common bacterial strains, including Staphylococcus aureus (71%), Escherichia coli (59%), and Klebsiella pneumoniae (64%). Furthermore, they demonstrated significant antifungal activity against plant pathogenic fungi, namely Aspergillus niger (65%), Aspergillus flavus (70%) and Fusarium oxysporum (61%).

The response of human macrophages to 3D printed titanium antibacterial implants does not affect the osteogenic differentiation of hMSCs.

Macrophage responses following the implantation of orthopaedic implants are essential for successful implant integration in the body, partly through intimate crosstalk with human marrow stromal cells (hMSCs) in the process of new bone formation. Additive manufacturing (AM) and plasma electrolytic oxidation (PEO) in the presence of silver nanoparticles (AgNPs) are promising techniques to achieve multifunctional titanium implants. Their osteoimmunomodulatory properties are, however, not yet fully investigated. Here, we studied the effects of implants with AgNPs on human macrophages and the crosstalk between hMSCs and human macrophages when co-cultured in vitro with biofunctionalised AM Ti6Al4V implants. A concentration of 0.3g/L AgNPs in the PEO electrolyte was found to be optimal for both macrophage viability and inhibition of bacteria growth. These specimens also caused a decrease of the macrophage tissue repair related factor C-C Motif Chemokine Ligand 18 (CCL18). Nevertheless, co-cultured hMSCs could osteogenically differentiate without any adverse effects caused by the presence of macrophages that were previously exposed to the PEO (±AgNPs) surfaces. Further evaluation of these promising implants in a bony in vivo environment with and without infection is highly recommended to prove their potential for clinical use.

Silver-poly(N-isopropylacrylamide-co-2-hydroxyethylmethacrylate) hybrid microgels with excellent catalytic potential

Silver nanoparticles have been loaded in poly(N-isopropylacrylamide-co-2-hydroxyethylmethacrylate) [P(NIPA-HEMA)] microgels through in situ reduction method. Presence of silver nanoparticles in micro-hosts was confirmed by different characterization techniques like UV–Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS) and Transmission electron microscopy (TEM). Morphologies of micro-hosts and composite microparticles were clearly shown by microscopic analysis to be core–shell types. Nanoparticles were mainly found in the shell region of micro-hosts due to which high catalytic activity was observed towards reduction of p-nitrophenol (p-NP). Value of observed rate constant of the reaction was evaluated by changing different variables such as concentration of p-NP, NaBH4, catalyst and temperature of the reaction medium. Dependence of catalytic activity upon temperature was observed as tunable and switchable under variation of temperature of the medium. Value of observed rate constant (kob) was found to increase from 0.127 per min to 0.232 per min as the temperature (T) increased from 21 °C to 30 °C. Then further rise in temperature dropped the rate constant value to 0.153 per min because of volume phase transition in polymeric network. Further increase in kob with T rise was according to Arrhenius behavior. The positive activation enthalpy (ΔH* = +49641.23 Jmol−1) and positive activation entropy (ΔS* = +70.43 Jmol−1 K−1) indicate that formation of activated complex is an entropy driven endothermic process. P(NIPA-HEMA)-Ag has potential to be used as an efficient catalytic system for degradation of toxic chemicals.

Blueberries as a Source of Energy: Physical Chemistry Characterization of Their Anthocyanins as Dye-Sensitized Solar Cells’ Sensitizers

This work aimed to show the possibility of applying anthocyanins extracted from blueberries following a straightforward path as potential impregnation dyes in dye-sensitized solar cells (DSSCs), particularly in the presence of co-adsorbents, such as silver nanoparticles, as an alternative in order to profit from large amounts of discarded fruits. Following a simple procedure, anthocyanins (mainly delphinidin-3-glucoside) were obtained from blueberries (Southern Highbush type). Complete characterization was carried out in order to prove the utility of delphinidin-3-glucoside as a sensitizer in DSSCs. The analyzed anthocyanin is suitable for sensitizing because of its high molar absorptivity values within the visible region of the light spectra, the adsorption ability to a FTO/TiO2 electrode (FTO, fluorine-doped tin oxide) as confirmed by Fourier transform infrared (FTIR) as well as thermogravimetry coupled to differential scanning calorimetry (TG-DSC), a potential oxidation value near 1 V, and adequate thermal as well as light stabilities. Moreover, the cell’s conversion efficiency is improved in the presence of silver nanoparticles, reaching 0.24% (nearly a 25% increase). The sum of all these characteristics points to the application of delphinidin-3-glucoside as a sensitizer in DSSCs, offering a technological use with potential interest for countries where agricultural production offers an abundant origin of extraction.

DEVELOPMENT, CHARACTERIZATION AND ANTIBACTERIAL PROPERTIES OF SILVER NANOPARTICLES LOADED SODIUM ALGINATE/XANTHAN GUM MICROBEADS FOR DRUG DELIVERY APPLICATIONS

Objective: The aim of this study is to create pH-responsive drug carriers, which are useful because they have the potential to improve treatment efficacy by controlling the release rate of ofloxacin from the polymer matrix. Methods: In the first step, silver nanoparticles (Ag NPs) were synthesized from silver nitrate using leaf extract of phyllanthus urinaria L as a reducing agent. In the second step, Ag-NPs-loaded polymeric microbeads were synthesized using sodium alginate (SA) and xanthan gum (XG) for controlled release of ofloxacin (OFLX). The developed microbeads were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), transition electron microscopy (TEM), Selected Area Electron Diffraction (SAED), and scanning electron microscopy (SEM). Swelling and in vitro release studies were performed at pH 2.0 and 7.4 at 37 °C. The in vitro antibacterial activity of microbeads were tested against S. mutans, K. pneumoniae, and B. subtilis. The release kinetics and mechanism were analyzed by fitting the release data into different kinetic models and the korsmeyer-peppas equation. Results: FTIR confirms the generation of silver nanoparticle and also the generation of polymeric microbeads. SEM studies reveal the developed microbeads are spherical in shape with rough surfaces. TEM studies reveal the size of 20-40 nm. XRD analysis reveals the molecular dispersion of DOX and the presence of silver nanoparticles in the polymeric matrix. Investigations of in vitro release and swelling studies show that the developed microbeads are relatively suitable for intestinal drug delivery because higher release rate was observed at pH 7.4. The developed microbead follows non-Fickian diffusion drug release mechanism. The created samples exhibited antimicrobial activity against S. mutans, K. pneumoniae, and B. subtilis. Conclusion: The results indicate that microbeads containing OFLX and silver nanoparticles are effective drug-delivery vehicles. A further warrant is required for the use of manufactured microbeads in drug delivery applications.

Fluorescence Evolution of Gold Nanoclusters in the Presence of Shapely Silver Nanoparticles and UV-Vis Light

Gold nanoclusters (Au NCs) belong to a class of materials that is highly fluorescent and biocompatible. Bovine serum albumin (BSA) protected gold nanoclusters (BSA-Au NCs) have been extensively used in biological applications due to their easy synthesis and relatively high quantum yield. Therefore, understanding the behavior of BSA-Au NCs in different chemical and physical environments is essential to enhance their application in biological systems. In this study, we investigated the effect of plasmonic nanostructures with different localized surface plasmon resonance (LSPR) wavelengths on the behavior of BSA-Au NCs by recording time-dependent fluorescence spectra in the presence of silver nanoparticles (AgNPs) with various shapes. However, we did not observe any conclusive LSPR-wavelength-dependent fluorescent behavior. Additionally, the fluorescence intensity of BSA-Au NCs exhibited gradual decay under light excitation, even at several hundred μW/cm2 in a fluorescence spectrometer, indicating that they are not as photostable as previously assumed. We found further that the photostability of BSA-Au NCs is affected by the wavelength of the incident light (370, 420, 480, and 550 nm), which can be accurately described using bi-exponential decay functions. Our study provides an easy in situ method to evaluate the photostability of Au NCs under different-wavelength light irradiation using a commercial fluorescence spectrometer.

Growth of New, Optically Active, Semi-Organic Single Crystals Glycine-Copper Sulphate Doped by Silver Nanoparticles

The purpose of this study is to modify all physicochemical properties of glycine–copper sulphate single crystals, such as crystal habits, molar mass, thermal stability, optical activity, and electrical properties. The novelty of this study is growth of glycine–copper sulphate single crystals doped by a low concentration of silver nanoparticles (SNPs) that improved both crystal habits and physicochemical properties. The originality of this work is that trace amounts of SNPs largely increased the crystal size. Crystals have molar stoichiometric formula [glycine]0.95, [CuSO4·5H2O]0.05 in the absence and presence of silver nanoparticles (SNPs) in different concentrations: 10 ppm, 20 ppm, and 30 ppm. The crystals’ names and abbreviations are: glycine–copper sulphate (GCS), glycine–copper sulphate doped by 10 ppm SNPs (GCSN1), glycine–copper sulphate doped by 20 ppm SNPs (GCSN2), and glycine–copper sulphate doped by 30 ppm SNPs (GCSN3). Dopant silver nanoparticles increased: crystallinity reflecting purity, transparency to UV-Vis. electromagnetic radiation, thermal stability, and melting point of glycine–copper sulphate single crystal. GCSN3 is a super conductor. High thermal conductivity of crystals ranging from 1.1 W·min−1·K−1 to 1.6 W·min−1·K−1 enabled attenuation of electromagnetic radiation and rapid heat dissipation due to good dielectric and polar properties. On rising temperature, AC electrical conductivity and dielectric properties of perfect crystal GCSN3 increased confirmed attenuation of thermal infrared radiation.

Preparation and Characterization of Silver Nanoparticles Using Rosemary and Olive Leaf Aqueous Extracts

Nano technology is single of the current technologies that are used in several playing field as well as agriculture, Nano-particles are produced in various ways, one of which is the biological method, which is one of the easy, fast, inexpensive and environmentally safe methods. This reference study deals with the latest studies on the manufacture of microorganisms and plant extracts, Biosynthesis of metallic nanoparticles using plant extracts. This study aims to use extracts of olive leaves and rosemary leaves as a biological agent to reduce silver nitrate to silver nanoparticles and capping solutions at pH 6.5 the color of the extracts changed from brown to dark green after adding silver nitrate solution indicating the formation of silver nanoparticles. These nano compounds were characterized using X-ray Diffraction, Atomic Force Microscopy and UV-Visible spectrophotometer. Silver nanoparticles were characterized using UV-visible radiation Spectral analysis which showed the highest peaks for olive leaf and rosemary extracts, respectively, at 450nm and 590nm, When examining the extracts of silver nanoparticles for olive leaves and rosemary leaves characterized using X-ray Diffraction a peak at 2θ= 40 appeared indicating the presence of silver nanoparticles, Finally, when diagnosing silver nanoparticles using atomic force electron technology The given microscopy (AFM) showed limited bandwidth high molecular assemblies of silver nanoparticles of olive leaf and rosemary leaf extract respectively (0-8.4) and (0-31) nm.

Biogenesis of silver nanoparticles from the shoot extract of Delonix regia its characterization (UV–Vis spectroscopy and SEM) and evaluation for antimicrobial potential

The current research work explores the production of silver nanoparticles using aqueous extracts of Delonix regia (Boj. ex Hook.) Raf. (Angiosperms; Fabaceae) shoots for the bioreduction of Ag metal and its antimicrobial activity. Fourier transform infrared spectroscopy (FTIR), Zeta potential, ultraviolet-visible spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) have been used to evaluate the produced silver nanoparticles (AgNPs). Both antibacterial and antifungal activity were examined against bacterial and fungal pathogens, viz., Escherichia coli and Bacillus subtilis, and fungal strains, viz., Fusarium oxysporum and Aspergillus niger. The presence of silver nanoparticles was observed by the color change, i.e., from pale yellow to dark brown. The zeta potential observed for the produced nanoparticle is -18mv. The SEM and XRD revealed the size of synthesized AgNPs, i.e., 35nm and SEM size lies in the range of 40-60 nm. UV-visible absorption spectra were found at wavelength 425 nm. The synthesized nanoparticles are cost-efficient and could be an alternative procedure for the peculiar production of nanoparticles and also act as potential antimicrobial agents.

Formulating silver nanoparticles from Syzygium Samagense flower buds extract

The study was to investigate the possibility of synthesizing silver nanoparticles by chemical reduction method using Syzygium Samagense flower bud extract as a green reducing agent. Various reaction conditions affecting the synthesis of silver nanoparticles were investigated including AgNO3 concentration (2 mM; 5 mM; 10 mM), volume ratio Vextract/VAgNO3 (2:30; 3:30; 4:30; 5:30), reaction temperature (50 – 80 °C), reaction time (15 - 60 mins). The presence of silver nanoparticles was detected by the combination of spectroscopy and X-ray diffraction (XRD) technology while the size of silver nanoparticles was determined by scanning electron microscopy (FE-SEM). The results showed that silver nanoparticles (owning an average size in the range of 20 - 35 nm) were successfully formulated with the highest yield when mixing the flower bud extract and AgNO3 solution (5 mM) with a ratio of 4:30 at 70 °C for 45 mins.

Characterization and drug delivery characters of nanocomposite hydrogels based on gamma-radiation copolymerization of poly (vinyl pyrrolidone) (PVP)/sodium alginate (AG)/silver NPs

Nanocomposite hydrogels were prepared by gamma-radiation copolymerization of poly (vinyl pyrrolidone) (PVP)/sodium alginate (AG) in the presence of silver nanoparticles (Ag NPs). The effect of irradiation dose and Ag NPs content on the gel content and swelling characters of PVP/AG/Ag NPs copolymers was investigated. In addition, the structure-property behavior of the copolymers was characterized by IR spectroscopy, thermogravimetric analysis (TGA) and x-ray diffraction (XRD). The drug uptake-release characters of PVP/AG/silver NPs copolymers, taking Prednisolone as a model drug, were studied. The study showed that the appropriate dose of gamma irradiation to achieve homogeneous nanocomposites hydrogel films and the highest swelling in water was 30 kGy, regardless of composition. The introduction of Ag NPs up to 5 wt % improved the physical properties and enhanced the drug uptake-release characters.

Low‐Cost, On‐Site, Nano‐Impact Detection of Silver Nanoparticles via Laser‐Ablated Screen‐Printed Microelectrodes

AbstractWith the ever‐growing presence of silver nanoparticles in consumer products, there is a need for cost‐effective and on‐site monitoring of their influence on our environment. Herein, we report the use of screen‐printed and laser‐ablated microelectrode arrays (SPMEAs) for the electrochemical detection of 20 nm‐sized silver nanoparticles (AgNPs) via collision electrochemistry. The electrodes’ morphology is optically analyzed and their electrochemical properties later characterized using cyclic voltammetry and impedance spectroscopy. The SPMEAs are calibrated using a AgNP concentration range of 1 to 100 pM, resulting in a linear dependency of 22 mHz pM−1 for the impact frequency. Finally, to demonstrate the possibility of future on‐site applications, an in‐house built portable nanoparticle detection (POND) device is used to measure Faradaic AgNP impacts on a SPMEA, in a solution contaminated with urea.

Comparison of bovine serum albumin and chitosan effects on calcium phosphate formation in the presence of silver nanoparticles.

The precipitation of calcium phosphates (CaPs) in the presence of more than one type of additive is of interest both from a fundamental point of view and as a possible biomimetic route for the preparation of multicomponent composites in which the activity of the components is preserved. In this study, the effect of bovine serum albumin (BSA) and chitosan (Chi) on the precipitation of CaPs in the presence of silver nanoparticles (AgNPs) stabilized with sodium bis(2-ethylhexyl)sulfosuccinate (AOT-AgNPs), poly(vinylpyrrolidone) (PVP-AgNPs), and citrate (cit-AgNPs) was investigated. In the control system, the precipitation of CaPs occurred in two steps. Amorphous calcium phosphate (ACP) was the first precipitated solid, which transformed into a mixture of calcium-deficient hydroxyapatite (CaDHA) and a smaller amount of octacalcium phosphate (OCP) after 60 min of ageing. Both biomacromolecules inhibited ACP transformation, with Chi being a stronger inhibitor due to its flexible molecular structure. As the concentration of the biomacromolecules increased, the amount of OCP decreased both in the absence and presence of AgNPs. In the presence of cit-AgNPs and two highest BSA concentrations, a change in the composition of the crystalline phase was observed. Calcium hydrogen phosphate dihydrate was formed in the mixture with CaDHA. An effect on the morphology of both the amorphous and crystalline phases was observed. The effect depended on the specific combination of biomacromolecules and differently stabilized AgNP. The results obtained suggest a simple method for fine-tuning the properties of precipitates using different classes of additives. This could be of interest for the biomimetic preparation of multifunctional composites for bone tissue engineering.