AgNPs Solution Research Articles

Effects of chitosan-containing silver nanoparticles or chlorhexidine as the final irrigant on the bond strength of resin-based root canal sealers.

Background. This study evaluated the combined effects of silver nanoparticles (AgNPs) and chitosan on the dentin bond strength of resin-based root canal sealers using the push-out test and scanning electron microscopy (SEM). Methods. This in vitro study was conducted on 72 extracted mandibular premolar teeth. All the teeth were decoronated perpendicular to the long axis to leave a 13-mm root length. The root canals were prepared, and the samples were randomly divided into seven experimental groups and one control group based on final irrigation solutions. All the final irrigation procedures were performed for one minute. The root canals were dried using paper points and filled with a resin-based sealer and gutta-percha points using a lateral condensation technique. Sections measuring 2 mm in thickness were taken from the apical, middle, and coronal thirds of each root using a cutting machine. The push-out test was performed using a universal testing machine. Results. The solution of AgNPs combined with 0.4% chitosan showed higher bond strength in the coronal region than a combination with 0.2% chitosan. Samples treated with 0.4% chitosan solution exhibited a higher bond strength than the 0.2% chitosan group. There were no significant differences between chlorhexidine (CHX) solution alone and in combination with 0.2% or 0.4% chitosan solution. Conclusion. The combination of chitosan and AgNPs was as effective as CHX in improving the bond strength of resin-based sealers.

Ultralight and flexible silver nanoparticle-wrapped “scorpion pectine-like” polyimide hybrid aerogels as sensitive pressor sensors with wide temperature range and consistent conductivity response

The demand for sensitive pressure sensors is increasing due to the rapid development of intelligent electronic equipment in high-tech fields such as aerospace and transportation. However, the high-temperature conditions encountered in aerospace applications pose challenges to the performance of flexible sensing materials used in related equipment. In this context, silver nanoparticles (AgNPs)-wrapped polyimide (PI) hybrid aerogels (PI/AgNPs aerogels) with scorpion pectine-like microstructures (SPM) were fabricated by freeze-drying the precursor solution, followed by a thermal imidization reaction and a dipping process with a AgNPs solution. The SPM grew vertically on the layered structure with a height between 20 and 40 μm. These PI/AgNPs provided sufficient structural strength as a support while providing recovery and contact points. The AgNPs were uniformly dispersed on the SPM (with a thickness of 78–120 nm on PI/AgNPs-1). The SPM-interface secondary response structure was used to realize an electrical response in a broad tension (the PI/AgNPs-2 aerogel has changed from −15.63 kPa under 30 % tensile stress to 69.25 kPa under 70 % compression stress). The hybrid aerogels had excellent sensing performance, including good resistance change (89 %), ultra-high sensitivity (6.9 kPa−1), the ability to detect different deformations (compression, tension, and bending), and low fatigue after 3000 load-unload cycles. In addition, these aerogels were able to withstand high temperatures up to 250 °C, and they showed good conductivity response consistency at high and room temperatures. These PI/AgNPs aerogels can be used as sensors in extreme conditions such as in aeroengine peripheral electronics for sensing and detecting external loads.

Preservation of Litchi Fruit with Nanosilver Composite Particles (Ag-NP) and Resistance against Peronophythora litchi.

Litchi (Litchi chinensis Sonn.) is susceptible to infection by Peronophythora litchi post storage, which rapidly decreases the sensory and nutritional quality of the fruit. In this study, the effects of nanosilver (Ag-NP) solution treatment on the shelf life of litchi fruit and the inhibition of P. litchi were examined, and the underlying mechanisms were discussed. For investigations, we used one variety of litchi (‘Feizixiao’), dipping it in different concentrations of Ag-NP solution after harvesting. Meanwhile, we treated P. litchi with different concentrations of Ag-NP solution. According to the data analysis, litchi treated with 400 μg/mL Ag-NPs and stored at 4 °C had the highest health rate and the lowest browning index among all the samples. In the same trend, treatment with 400 μg/mL Ag-NPs produced the best results for anthocyanin content, total soluble solids content, and titratable acidity content. Additionally, according to the results of the inhibition test, 800 μg/mL Ag-NP solution had a 94.97% inhibition rate against P. litchi. Within 2–10 h following exposure to 400 μg/mL Ag-NP solution, the contents of superoxide dismutase, peroxidase, and catalase in P. litchi gradually increased and peaked, followed by a gradual decline. At this time, the integrity of the cell membrane of P. litchi could be broken by Ag-NP solution, and the sporangia showed deformed germ tubes and abnormal shapes. Taken together, these results suggested that Ag-NP treatment inhibited respiration and P. litchi activity, which might attenuate litchi pericarp browning and prolong the shelf life of litchi. Accordingly, Ag-NPs could be used as an effective antistaling agent in litchi fruit and as an ecofriendly fungicide for the post-harvest control of litchi downy blight. This study provides new insights into the application of Ag-NP as an antistaling agent for fruit storage and as an ecofriendly fungicide.

A new ratiometric fluorescent detection of Glucose-6-phosphate dehydrogenase enzyme based on dually emitting carbon dots and silver nanoparticles

The defect of Glucose-6-phosphate dehydrogenase (G6PD) is a considerable enzyme deficiency globally and causes many diseases. Here the ratiometric fluorescent method was designed for detecting G6PD based on silver nanoparticles (AgNPs) and dually emitting carbon dots (DECDs) that exhibited dual emission fluorescence peaks in 470 and 523 (nm) under the single excitation wavelength at 330 nm. In the solution of mixed DECDs and AgNPs, the internal filter effect (IFE) causes a reduction of blue fluorescence of DECDs, because spectral overlapping happened between the emission of DECDs and the absorption of AgNPs (near 400 nm). In the absents of G6PD, the substrate of this enzyme (NADP+) was exited in the solution, causing the aggregation of AgNPs, and the absorption of aggregated AgNPs was shifted to about 520 nm. Therefore, recovering the blue fluorescence is happened. The ratiometric fluorometric assay is based on rationing the emissions (I470/I523). This method has a wide detection range (0.009–21 (U mL−1)) with a low detection limit of 0.006 (U mL−1). The assay was used to determine G6PD in spiked blood samples; the recovery values were obtained in the range of 96.19 % to 110 %. This cheap and fast method allows detecting G6PD on-site with visual detection by analyzing fluorescence color shades.

Evaluation of the Antibacterial Efficacy of QMix and AgNP Solutions in Root Canals of Primary Molars: An In-Vitro Study.

PurposeThe study aimed to evaluate QMix2in1 and silver nanoparticles (AgNPs) solution in eliminating Enterococcus faecalis (E. faecalis) bacteria within root canals of primary molars.Materials and methodsThe study sample consisted of 45 extracted primary molars, which were divided into three groups: Group 1 (control) NaOCl 5.25%, Group 2 (experimental) QMix2 in 1, and Group 3 (experimental) AgNPs 4000 ppm. The root canals were sterilized within an autoclave and then contaminated with E. faecalis bacteria. The root canals were irrigated for five minutes in a quantity of 3 ml using a 31-gauge irrigation needle, and then bacterial smears were taken.ResultsSodium hypochlorite, AgNPs, and QMix2in1 effectively reduced the bacterial count of Enterococcus within root canals of primary molars. There were statistical differences between all groups. QMix2in1 solution showed the greatest antibacterial efficacy, then NaOCl solution and AgNPs solution. ConclusionAll irrigation solutions used are effective in eliminating E. faecalis. QMix2in1 can be considered a good alternative to sodium hypochlorite in irrigation root canals of primary teeth.

Corrosion inhibition performance of silver nanoparticles embedded-gloss paint on carbon steel and aluminium substrates in 2.0 M H2SO4 solution

Corrosion control of metals in aggressive environments has attracted a lot of attention due to its associated economic losses. However, most corrosion control techniques have not satisfactorily minimized these losses. This study examined the inhibition effects of silver nanoparticles (AgNPs) incorporated in gloss paint on corrosion of carbon steel and aluminium in 2.0 M H2SO4 solution. The AgNPs were biosynthesized via green chemistry and characterized using Fourier Transform Infrared, UV-Vis spectrometer, and Transmission Electron Microscope. Samples of carbon steel and aluminium were uniformly coated with a thin layer of gloss paint mixed with AgNPs solution at five different concentrations of 0, 5, 10, 15, and 20 µg/ml. The inhibition efficiency of the AgNPs modified paint was conducted via gravimetric, gasometric, and potentiodynamic polarization analyses. Results of the gravimetric analysis revealed an increased weight loss with an increased period of exposure and decreased concentration of AgNPs in the paint. The corrosion rates for the mild steel and aluminium samples were 0.051 and 0.005 mmpy with inhibition efficiencies of 42% and 69%, respectively, when immersed in 20 µg/ml AgNPs-incorporated coating and exposed for 120 hours. Potentiodynamic polarization analysis revealed that the presence of AgNPs in the paint (as inhibitor) retarded the anodic dissolution by the formation of protective films on the mild steel and aluminium sample surfaces. The evolution of hydrogen gas from 20 µg/ml AgNPs-incorporated coating was significantly reduced by 81% and 14% for mild steel and aluminium, respectively when compared with the control samples at 200 minutes of exposure. These results revealed that the incorporation of AgNPs into the gloss paint matrix minimizes the degradation due to corrosion of the mild steel and aluminium samples.

Structural and Physicomechanical Properties of an Active Film Based on Potato Starch, Silver Nanoparticles, and Rose Apple (Syzygium samarangense) Extract

In the current research work, active films were made from potato starch (PS) and AgNP solution comprising of silver nanoparticles (AgNPs) and rose apple extract (RE) via the casting method at various concentrations. AgNP solution in the PS matrix significantly altered the physical properties such as opacity, water vapor permeability mechanical property, solubility, and swelling index of the films. The influence of AgNP solution on the properties of the films was deeply examined. The results found that the 15% AgNP solution films exhibited better physicochemical properties. The presence of AgNP solution in the PS matrix significantly improved the properties of active films which is evident from the results of FTIR and SEM. Results show that AgNPs and PS were uniformly mixed and formed continuous and homogenous films without bubbles and cracks. In addition, the AgNP solution in the films significantly improved the antibacterial activity against S. aureus than P. aeruginosa in the films.

Efficient removal of 110mAg nanoparticles (110mAg Nps) in nuclear wastewater by Amines-containing anionic adsorbent PP-g-GMA@EDA

110mAg nanoparticles (110mAg Nps) is a radioactive contaminant in the process wastewater of nuclear power plants. In this study, the novel material containing amines PP-g-GMA@EDA as the adsorbent is proposed for the removal Ag Nps. PP-g-GMA@EDA is synthesized by γ ray-induced simultaneous irradiation grafting and its removal performances for Ag Nps from aqueous solutions has been studied. In Ag Nps solution at different pH values, PP-g-GMA@EDA possesses better removal efficiency than the commercial resin IRN9766 commonly used in nuclear power plants, especially at pH 4. XPS helps confirm that the adsorption mechanism is mainly ion exchange to negatively-charged Ag Nps by protonated secondary amines on the adsorbent. At the optimal pH 4, the effects of different parameters such as the initial Ag Nps concentration, the ratio of adsorbent dosage to solution volume and the adsorption time on adsorption performances are considered. 100% adsorption efficiency of Ag Nps can be achieved and the maximum adsorption capacity is 101.44 mg/g. The Langmiur isotherm model and the pseudo-first-order kinetic model better describe the adsoption process. In the simulated nuclear power plant process wastewater, even though the concentration of competitive ions is 40 times that of Ag Nps, the removal efficiencies still maintain above 85%. In addition, 5 wt% ammonia water can effectively desorb Ag Nps from the used adsorbent to ensure the recyclability of PP-g-GMA@EDA. The well designed adsorbent with excellent removal efficiency and selectivity provides a very efficient, sustainable, and industrially feasible way for Ag Nps decontamination from nuclear wastewater.

A silver-nanoparticle-based chemosensor for optical detection of captopril

Captopril is an angiotensin-converting enzyme commonly used to treat high blood pressure and to improve survival after a heart attack. Considering the importance of the assay of this drug, the authors propose a simple and cost-effective colorimetric technique for its quantitative determination. The detection strategy was based on the redshift of the surface plasmon resonance band of silver nanoparticles (AgNPs) induced by the action of captopril molecules. Under optimal experimental conditions, the interaction of AgNPs with captopril molecules in the presence of barium ions induces the aggregation of AgNPs. The final result of this process is an observable change in the color of the tested solution from pale yellow to light brown. The experiments showed that there is a linear relationship between the absorbance of the AgNP solution and the captopril concentration at about 720 nm. Thus, it is possible to assay the captopril amount just by measuring the absorbance of the examined solution at this wavelength. The calibration curve was linear in the range 1.0–6.0 μM captopril with a detection limit equal to 0.4 μM. The proposed strategy was successfully applied to the determination of captopril in pharmaceutical preparations.

Biosintesis nanopartikel perak (AgNP) menggunakan Bacillus firmus E65 dan aktivitasnya terhadap mikroba patogen

Silver (Ag) in ionic form is toxic to microbial cells, but is environmentally friendly and safe for humans. This study aims to synthesize silver nanoparticles (AgNP) using Gram-positive bacterial isolate (B. firmus E65) as a bioreductor and to test its activity as an antimicrobial against Eschericia coli, Xanthomonas oryzae pv. oryzae (Xoo) and the fungus Colletotrichum gloeosporioides under in-vitro assays. AgNP was obtained by adding bacterial culture supernatant B. firmus E-65 to 5mM AgNO3 solution. The formation of AgNP was observed by changing the color of the solution after incubation at 37 °C for 72 hours. The UV-Vis spectrophotometer measurement to AgNP solution showed a maximum wavelength of 425 nm. The particle size of AgNP was 252.1 nm with intensity of 98.90 %. The result of bioassay against E. coli showed the greatest inhibition at 50 % AgNP (degree of inhibition (DI) =96.15 %), followed by 25 % AgNP (DI=76.92 %), and 12.5 % AgNP (DI=53.84 %). The bioassay against Xoo showed the greatest degree of inhibition was at AgNP 50 % (DI=92.85 %), followed by 25 % AgNP and 12.5 % AgNP (DI=85.71 %). Meanwhile bioassay against C.gloeosporioides, the greatest inhibition was observed at 25 % AgNP (DI=94.35 %), followed by 50 % AgNP (DI=91.9 %).

Incorporation of silver nanoparticles in a kaolin hollow fiber membrane for efficient removal of Enterobacter cloacae and Escherichia coli from aqueous solutions

Kaolin hollow fiber membranes were produced by the phase inversion method and silver nanoparticles (AgNPs) were sequentially impregnated in the fiber lumen side. The composite membranes were applied to treat aqueous solutions contaminated with Enterobacter cloacae and Escherichia coli. The prepared pristine kaolin hollow fibers presented an asymmetric pore size distribution. According to mercury intrusion analyses, the sponge like layer presented pore sizes between 1.14 and 2.16 μm, while the micro-voids in the finger like layer presented pore sizes between 7.86 and 9.17 μm. The kaolin hollow fibers presented water permeability of 8.46 ± 0.17 L h−1 m−2·kPa−1 and mechanical resistance of 103.58 ± 14.41 MPa. The AgNPs were properly synthetized and, according to spectroscopic analyses, the AgNP solution presented a single broad peak centered at 400 nm, which indicates a uniform dispersion of the synthetized AgNPs. The synthetized AgNPs presented a spherical and pseudospherical geometry, with average hydrodynamic size of 81.71 ± 8.05 nm, polydispersity index of 0.262 ± 0.012 and zeta potential of −20.7 ± 2.6 mV, which indicate a suitable AgNP stability in the aqueous suspension. The AgNPs were successfully impregnated in the lumen side of kaolin hollow fibers at a concentration of 0.51 ± 0.04 mg cm−1. Energy dispersive spectroscopy images showed that the AgNPs were more concentrated in the hollow fiber inner layer and a homogenous distribution of AgNPs were observed through the fiber cross-section. After AgNP impregnation, the composite hollow fiber membranes presented water permeability of 5.22 ± 0.32 L h−1 m−2 kPa−1. The pristine kaolin membrane enabled a log10 reduction value (LRV) of 2.47 ± 0.05 and 3.72 ± 0.13 for filtrations of aqueous solutions with E. cloacae and E. coli, respectively. For the kaolin hollow fiber membrane impregnated with AgNPs, the LRV value increased to 4.38 ± 0.83 and 4.35 ± 0.25 for filtrations of aqueous solutions with E. cloacae and E. coli, respectively. Thus, the synergetic action of the kaolin membranes impregnated with AgNPs enabled a bacterial reduction greater than 99.9%. The AgNPs decreased the permeate flux through the membrane but, for the filtration of the E. cloacae suspension, mitigated the cake formation on the membrane surface.

Synergistic sorption performance of karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ metal nanoparticle for organic pollutants

In this work, we tailor facile hydrogels nanocomposite (HNC) based on sustainable karaya gum for water treatment. Karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ silver nanoparticle (KG-cl-P(AAm-co-AN)@AgNPs) HNC were made by an aqueous free radical in situ crosslink copolymerization of acrylamide (AAm) and acrylic acid (AA) in aqueous solution of KG-stabilized AgNPs. FTIR, XRD, DTA–TGA, SEM, and TEM were used to characterize HNC. The hydrogels' swelling, diffusion, and network characteristics were investigated. The removal efficiency of HNC was found to be 99% at pH 8 for a crystal violet (CV), dose of 0.02 g after 1 h. Dye adsorption by these hydrogels was also investigated in terms of isotherms, and kinetics. The dye's exceptionally high adsorption capacity on HNC for CV removal is explained by H-bonding interactions, as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules (Qmax, 1000 mg/g). The HNC can be regenerated with 0.1 M HCl and reused at least 10 times maintaining over 68% dye removal. The loading of AgNPs into the polymeric matrix of KG-cl-P(AAm-co-AN) significantly increases the removal percentage of CV dye from its aqueous solution, according to this study.

The new identity of cellulose pulp: A green silver nanoparticles support for highly efficient catalytic hydrogenation of 4-nitrophenol

The uniquely interconvertible transformation of cellulose pulp and paper shows great potential as smart materials for environment remediation. However, performing liquid-phase catalytic reactions involving hydrogenation steps under mild conditions and ambient temperature remains challenging. Herein, we report a facile and eco-friendly strategy to fabricate low-cost, highly effective, and stable pulp-supported silver nanoparticles (AgNPs/pulp). The pulp phase is used to maintain the high catalytic efficiency of the AgNPs/pulp catalyst, while the paper phase remains high stability as the filling material in the reaction column. The as-prepared AgNPs/pulp catalyst exhibits excellent catalytic activity toward NaBH4-mediated reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with a turnover frequency of 605.1 h−1 and a k value of 24.9 × 10−3 s−1 at room temperature, which outperforms most of reported cellulose-supported catalysts. Impressively, the AgNPs/pulp catalyst shows outstanding durability during a continuous operation for 72 h. Such excellent performance can be attributed to the uniform dispersion of the AgNPs/pulp in solution and uniform distribution of Ag NPs on the fiber surface of cotton pulp, which greatly improve the accessibility of reactants and active sites as well as metal-support interactions. This work provides new insights into the understanding of catalytic hydrogenation of 4-NP, which could pave the way for rational design of novel cellulose-based catalysts for organic wastewater treatment.

Electrochemical Determination of Nanoparticle Size: Combined Theoretical and Experimental Study for Matrixless Silver Nanoparticles.

A chronoamperometric procedure for the preparation of silver nanoparticles (AgNPs) in aqueous systems with no extra added stabilizing agents is presented. The uniqueness of the prepared nanoparticle systems was explored by theoretical considerations. The proposed theoretical model predicts the structural parameters of the obtained nanoparticle system. The parameters required for the calculations (the zeta potential, conductivity, and effective diffusion coefficient of ionic silver) are available from independently performed measurements. Chronoamperometry at a microelectrode was employed for the evaluation of the effective diffusion coefficient of ionic silver present in the AgNP solution. The values of AgNP radii predicted by the theoretical model for the selected samples were compared to those obtained by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) methods. Because of the high polydispersity of the prepared nanoparticle samples, DLS results were overestimated in comparison to both: the TEM results and some theoretical predictions. By correcting the theoretical predictions by the Debye length, the calculated nanoparticle sizes become comparable (within their expanded uncertainties) to those measured in TEM images, especially for the nanosystems at early stages of their formation via the electrosynthesis process.

Effect of Silver Nanoparticles Treatments on Some Characteristics of “Santander” Lily Cultivar

The use of silver nanoparticles (AgNPs) in the fields of agriculture and horticulture has been increasing recently due to contribution to seed germination, plant growth and development, flowering, yield, and physiological improvements. This research aimed to investigate the effects of silver nanoparticles on the growth and flowering characteristics of the 'Santander' lily (Lilium L.) variety and to determine its potential for use in cultivation. Before planting the plant bulbs immersed in AgNPs solutions of 0 (control), 50, 75, 100, 125 and 150 ppm. After harvest; weight, circumference, height, root length, fresh and dry weight, stem root length, fresh and dry weight of stem, plant height, plant stem diameter, fresh plant weight, bud number and vase life were determined. As a result; it has been indicated that AgNPs solutions in different concentrations increased the quality and quantity of cut flowers and bulbs in lily plants. AgNPs increased an average of 26.29% when compared with control in all morphological characteristics except for the vase life. In the light of these findings, AgNPs applications can be preferred as a method that can be used on lily cultivation and reproduction. Nevertheless, considering the deficiency of treatments of AgNPs in lily plants and their poorly known effect on plants, further detailed studies are necessary.

The antibacterial potential of biosynthesized silver nanoparticles using beech bark and spruce bark extracts

Abstract Introduction: Lately, nanotechnology focuses on the green synthesis of AgNPs, using different plant materials, as this method is accessible, cost-efficient, and ecological. The study aimed to investigate the antibacterial potential of AgNPs synthesized using beech/spruce bark extracts (BBE/SBE) and silver salts (acetate/nitrate). Method: The growth rates of Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 were evaluated in the presence of the AgNPs solutions. The checkerboard method was performed to evaluate if these solutions exert synergistic activity with gentamicin. Results: For E. coli, synergistic effects were observed for the combination of gentamicin 0.25mg/L with AgNP BBE Nit (0.145mg/mL) and with AgNP SBE Ac (0,09mg/mL). For S. aureus, no synergistic effects were observed. Overall, the AgNP BBEs solutions combined with gentamicin presented lowest values of fractional inhibitory concentration than the ones registered for the combination of AgNP SBEs with gentamicin, for both bacterial strains. The growth rate of S. aureus was inhibited by all the tested AgNPs at the measured time points. For E. coli, after 24 hours of incubation, the growth rate was inhibited only in the presence of AgNP SBE Ac. After 6 hours of incubation, the growth rate of E. coli was almost stationary in the presence of AgNP BBE Nit. Conclusions: The biosynthesis of AgNPs is a valuable choice for obtaining substances with antibacterial potential.

Supramolecular nanogels based on gelatin–cyclodextrin-stabilized silver nanocomposites with antibacterial and anticancer properties

An effective method for reducing silver ions using gelatin (Gel) and 2-hydroxypropyl-β-cyclodextrin (HPCD) hydrogels, which stabilize silver at various concentrations is described. The formation of AgNPs in solution, as well as Gel-HPCD nanogels, is confirmed by the surface plasmon resonance (SPR) band at 420–440 nm in the UV–Vis spectrum. The resulting Gel-HPCD and Gel-HPCD/AgNPs composites are characterized using various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and thermogravimetric analysis (TGA). SEM images showed that the porous structure and the AgNPs are homogeneously dispersed throughout the Gel-HPCD/AgNP composites network. The AgNPs in the Gel-HPCD/AgNPs composite is crystalline, with spherical particles having an average size of 7.0 ± 2.5 nm, as determined by TEM. The Gel-HPCD/AgNPs composites are strongly effective against both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The assembled antibacterial Gel-HPCD/AgNPs composites are also assessed for their cytotoxic and anticancer activities using HCT-116 cancer cells. The results suggest that Gel-HPCD/AgNPs composites could be used as effective therapeutics in the future in tissue engineering applications, as their bactericidal properties and low toxicity make them ideal for clinical use.

Ultrastructural and molecular implications of ecofriendly made silver nanoparticles treatments in pea (Pisum sativum L.)

BackgroundSilver nanoparticles (AgNPs) are the most widely used nanomaterial in agricultural and environmental applications. In this study, the impact of AgNPs solutions at 20 mg/L, 40 mg/L, 80 mg/L, and 160 mg/L on cell ultrastructure have been examined in pea (Pisum sativum L) using a transmission electron microscope (TEM). The effect of AgNPs treatments on the α, β esterase (EST), and peroxidase (POX) enzymes expression as well as gain or loss of inter-simple sequence repeats (ISSRs) markers has been described. ResultsDifferent structural malformations in the cell wall and mitochondria, as well as plasmolysis and vacuolation were recorded in root cells. Damaged chloroplast and mitochondria were frequently observed in leaves and the osmiophilic plastoglobuli were more observed as AgNPs concentration increased. Starch grains increased by the treatment with 20 mg/L AgNPs. The expressions of α, β EST, and POX were slightly changed but considerable polymorphism in ISSR profiles, using 17 different primers, were scored indicating gain or loss of gene loci as a result of AgNPs treatments. This indicates considerable variations in genomic DNA and point mutations that may be induced by AgNPs as a genotoxic nanomaterial. ConclusionAgNPs may be used to induce genetic variation at low concentrations. However, considerations should be given to the uncontrolled use of nanoparticles and calls for evaluating their impact on plant growth and potential genotoxicity are justified.

Establishment of a fiber optic sensor coupled to the plasmonic effect of silver nanoparticles in glucose concentration monitoring

Introduction: Diabetes is an extremely dangerous disease due to the disorder of glucose metabolism in the body leading to serious complications and the cause other dangerous diseases. Therefore, the continuous monitoring of glucose levels in the body is particularly important in the prevention and treatment of this disease. Optical fiber sensors that apply the LSPR effect of silver nanoparticles show great potential in the field of sensors that enable precise label-free monitoring of analyte concentrations with high sensitivity, which is receiving much attention. Methods: Based on the sensitivity of the LSPR effect on the surface of AgNPs to the dielectric properties of the medium, namely the refractive index of the analyte solution. Variation in the LSPR conditions of AgNPs leads to either donation or reduction in optical power. Based on that mechanism, the fiber was used as a waveguide and was immobilized on a self-assembled monolayer of AgNPs 1 core surrounded by a microfluidic channel that allows the analyte solution to pass through the sensing area through a biological pump. This process of changing the capacity allows the assessment of glucose concentration in solution to a very small degree of change. Results: AgNPs of about 90 nm in size were quickly and simply synthesized with high stability and uniformity by chemical reduction with an Ethylene glycol reducing agent as demonstrated by FESEM, and DLS results. The LSPR wavelength of AgNPs solution observed by UV-vis spectrum is 435 nm. At the same time, a fiber-optic sensor system that monitors glucose concentration changes has also been successfully established with a sensitivity of 0.025 RIU corresponding to a detection of limited (LOD) of up to 0.35 mM. Conclusions: The optical fiber optical sensor based on the LSPR phenomenon of AgNPs was initially established and showed high sensitivity in detecting and monitoring changes in glucose concentration without the use of complex markers or enzymes. The compact size of the fiber sensor opens up the potential for integration into handheld optical devices to help monitor health more proactively. Keywords: Silver nanoparticles, LSPR, Glucose sensor, optical sensor, detection of limited.

The Combination of Laser and Nanoparticles for Enamel Protection: An In Vitro Study.

Introduction: Dental decay is caused by the fermentation of carbohydrates and the production of acids which demineralize teeth. The fermented food debris lowers the pH under 5.5, resulting in the mineral loss of teeth. Anti-decay factors are used to reduce decay rates and increase dental protection. Methods: Fifteen sectioned teeth samples were immersed in Ag NPs solution and then irradiated with laser pulses. Structures, morphologies, chemical compositions and microhardness were studied using the Vickers micro-hardness tester, energy dispersive x-ray machine, atomic force microscope and scanning electron microscopes. Results: Nine mature extracted human third molars, cleaned and placed in plastic molds then filled with a warm epoxy resin, were sectioned longitudinally and polished. The samples were then cleaned ultrasonically and stored in distilled water and taken immediately one by one for laser treatment. Sharper, overlapping, interconnected rods and higher resistance against enamel decay were demonstrated with little alterations of the mineral percentages of the teeth samples. Conclusion: The combination of laser light and silver annoparticles improved the decay resistance; where regular inter-connected chain-like merged grains were formed. These laser-induced modifications in enamel components have reduced the lattice stress and enamel solubility and improved resistance against decay. The computer model indicated a possible prediction of the laser-treated profile prior to laser treatment.