Acid Functionalized Silver Nanoparticles Research Articles

Alginic acid-functionalized silver nanoparticles: A rapid monitoring tool for detecting the technology-critical element tellurium

The increasing global demand for tellurium, driven by its critical role in alloys, photovoltaic devices, and electronics, has raised concerns about its environmental pollution and neurotoxicity. In response, the potential of alginic acid (AA), a renewable, low-cost, and sustainable biopolymer, was explored for the biosynthesis of ultra-small silver nanoparticles (AgNPs) and their application in the detection of tellurium (Te(IV)). The effect of key synthesis parameters on desired physicochemical properties and yield of AgNPs was established to ensure high specificity and sensitivity towards Te(IV). The purified AgNPs with AA surface ligands were utilized to demonstrate a ratiometric absorbance sensor that exhibits excellent linearity and nanomolar-level affinity. This approach achieved a high correlation coefficient of ∼ 0.982, with a low detection limit of about 22 nM. Further investigations into the effect of pH, ionic strength, and organic molecules were conducted to elucidate detection performance and molecular understanding. The detection mechanism relies on the coordination between Te(IV) ions and the carboxylate groups of AA, which initiates aggregation-induced plasmon coupling in adjacent AgNPs. The capability of this analytical method to monitor Te(IV) in real-world water samples features its rapidity, user-friendliness, and suitability for point-of-care monitoring, making it a promising alternative to more complex techniques.

Tannic Acid-Functionalized Silver Nanoparticles as Colorimetric Probe for the Simultaneous and Sensitive Detection of Aluminum(III) and Fluoride Ions.

In this study, we employed tannic acid (TA)-functionalized silver nanoparticles (TA@AgNPs) as colorimetric probe for the simultaneous and sensitive detection of Al(III) and F- ions. The proposed sensor was based on the aggregation and anti-aggregation effects of target Al(III) and F- ions on TA@AgNPs, respectively. Because of the strong coordination bond between Al(III) ions and TA, the addition of Al(III) ions to TA@AgNPs could cause aggregation and, hence, result in a significant change in the absorption and color of the test solution. Interestingly, in the presence of F- ions, the aggregation effect of Al(III) ions on TA@AgNPs can be effectively prevented. The extent of aggregation and anti-aggregation effects was concentration-dependent and can be used for the quantitative detection of Al(III) and F- ions. The as-proposed sensor presented the sensitive detection of Al(III) and F ions with limits of detection (LOD) of 0.2 and 0.19 μM, respectively. In addition, the proposed sensor showed excellent applicability for the detection of Al(III) and F- ions in real water samples. Moreover, the sensing strategy offered a simple, rapid, and sensitive detection procedure and could be used as a potential alternative to conventional methods, which usually involve sophisticated instruments, complicated processes, and a long detection time.

Sensitive Determination of Stevioside by Surface-Enhanced Raman Spectroscopy (SERS) Using 4-Mercaptophenylboric Acid Functionalized Silver Nanoparticles (Ag NPs)

Stevioside is an important natural sweetener in food and beverages. There are concerns about its safety, but few methods for its determination. Silver nanoparticles (Ag NPs) functionalized with 4-mercaptophenylboronic acid (4-MPBA) were successfully used to determine stevioside in beverages based upon surface-enhanced Raman spectroscopy (SERS). The Ag NPs self-assemble with 4-MPBA through the covalent interaction of their sulfhydryl groups with the metal particles. Boronic acid groups bonded to 1,2-/1,3-diol groups form cyclic boronic esters with strong affinity and significant specificity for stevioside. The combination of the two leads to an alteration of the 4-MPBA vibrational mode. The change in the orientation of the moiety and the charge transfer resulted in a significant increase of the SERS signal. The substrates showed strong specificity and sensitivity to stevioside in the presence of other sweeteners. Also, the substrate modification conditions were optimized, including the time, ratio, and concentration. The limit of detection (LOD) for stevioside in beverages was 0.210 μmol/L, and the recovery was from 98.4% to 109.4%. In summary, the presented SERS method provides high sensitivity for stevioside.

Effect of Ligand Concentration on the Stability and Copper (II) Sensing Performance of Humic Acid-Functionalized Silver Nanoparticles

Detecting heavy metals in water is necessary to ensure its safety. However, current detection methods require costly equipment, making heavy metal monitoring challenging. Colorimetric detection of heavy metals using silver nanoparticles (AgNPs) relies on the optical spectra changes when it detects an analyte. We have previously shown that a colorimetric assay comprised of humic acid - functionalized AgNPs (HA-AgNPs) can selectively detect copper ions in water. Here, we investigated the effect of humic acid concentration on the stability of HA-AgNPs and their ability to detect copper. HA acts as a capping agent around the AgNPs, making them stable even for up to 48 days of storage in both ambient and cold storage environments. At critical HA concentrations of 5 mg L-1 and beyond, the changes in the optical properties of the HA-AgNPs are linearly dependent on Cu (II) concentration. Below this critical HA concentration, Cu (II) sensing is futile. The most stable HA-AgNPs is at HA = 25 mg L-1 based on zeta potential measurements, while the best assay for colorimetric copper (II) detection is at HA = 50 mg L-1, giving the lowest detection limit of 4.35 mg L-1 and R2 = 0.999 within a dynamic linear range of 0.00 to 1.25 mM Cu (II). We have shown that the ligand concentration is critical for achieving stable AgNP assays for heavy metal detection.

Injectable sodium alginate hydrogel loaded with plant polyphenol-functionalized silver nanoparticles for bacteria-infected wound healing

A novel injectable hydrogel dressing (GA@AgNPs-SA) with long-term antimicrobial effect is developed that can accelerate the closure of bacteria-infected wounds. The hydrogel dressing was prepared by cross-linking sodium alginate molecular chains and gallic acid functionalized silver nanoparticles (GA@AgNPs) via calcium ions to form a three-dimensional network. The hydrogel dressing demonstrates excellent biocompatibility and can achieve a sustainable release of silver ions, ensuring a long-term antibacterial activity and inhibiting biofilm formation. Moreover, an in vivo study demonstrates that the GA@AgNPs-SA hydrogel can effectively decrease the expression of IL-6 and TNF-α to alleviate the inflammatory response, and promote angiogenesis by upregulating CD31, α-SMA and VEGF expression, thus significantly accelerating the repair of infected wounds. Given these interesting properties, this antibacterial hydrogel has great potential for application in the clinical care of bacteria-infected wounds.

Effects of amino acid-functionalized silver nanoparticles on lysozyme amyloid fibrillogenesis

Amyloid fibrillogenesis of proteins have been considered as the major cause behind several degenerative diseases. Nanoparticles have been found to have great potential as a substrate for designing amyloid fibril inhibitors and/or modulators. This is mainly due to its ideal characteristics, such as small size, high surface area-to volume ratio, and modifiable surface. This study is aimed at examining the influence of amino acid-modified silver nanoparticles on amyloid fibril formation. We first synthesized and characterized the proline- and cysteine-functionalized silver nanoparticles (Pro-AgNP and Cys-AgNP). Next, the effects of functionalized silver nanoparticles on amyloid fibrillogenesis and structural changes of hen lysozyme were examined using various spectroscopic and biophysical tools. Our results showed that Pro-AgNP/Cys-AgNP dose-dependently suppressed lysozyme amyloid fibrillogenesis, whereas negligible fibril-inhibiting effect was observed in the bare AgNP or proline/cysteine. Moreover, reduced solvent exposure and α-to-β transition were detected in lysozyme upon the addition of Pro-AgNP/Cys-AgNP. Finally, the nature of interactions between lysozyme and Pro-AgNP/Cys-AgNP was further examined using fluorescence quenching and molecular docking. By altering the properties of nanoparticles to design suitable nanoprobes, we have shown that amyloid fibrillogenesis can be controlled.

Microwave-assisted and chemically tailored chlorogenic acid-functionalized silver nanoparticles of Citrus sinensis ingelmatrix aiding QbD design for the treatment of acne.

Numerous studies have shown that various products of Citrus sinensis, for example, crude extracts, essential oil, and purified components, possess anti-acne properties. However, the development of chlorogenic acid-functionalized silver nanoparticles of C.sinensis in gel matrix aiding QbD design has not been evaluated for acne treatment. In this study, we have developed chlorogenic acid-functionalized silver nanoparticles of C.sinensis in a gel matrix employing a QbD approach for acne treatment. Citrus sinensis extract-loaded silver nanoparticles were functionalized with chlorogenic acid, which acted as a bio-reducing agent and further improved anti-acne properties. The developed formulation was optimized via Box-Behnken Design. The formulation morphology was evaluated by transmission electron microscopy (TEM). The release profile of C.sinensis extract formulation was assessed by an in vitro release study and confocal laser scanning microscopy (CLSM). Moreover, the characterization study of the gel was performed that included an evaluation of the extrudability and spreadability of the developed gel. Furthermore, the anti-oxidant efficacy of AgN-CA formulation was validated using the DPPH test. The results showed a particle size of 71.78 nm, a polydispersity index of 0.297, a zeta potential of -36.12 mV, and an entrapment efficiency of 79.42% ± 6.79%. The results also indicated a uniform particle size. The release profile of C.sinensis extract revealed that 73.95% of the drug was released, whereas CLSM pictures of mice skin evidently demonstrated that the rhodamine B-treated AgN-CA gel penetrated much more extensively in comparison to the control. Furthermore, the anti-oxidant efficacy of AgN-CA formulation was validated using the DPPH test. Moreover, the characterization study of the developed gel, including its extrudability and spreadability, was found to be 16.02 ± 3.21 g and 30.73 ± 5.94 g cm/s, respectively. Also, texture analysis findings revealed that AgN-CA gel had firmness, consistency, cohesiveness, and viscosity index of 159.69 g, 634.95 g s, -116.33 g, and -501.80 g s, respectively, indicating that the AgN-CA gel was stable. The current study showed that AgN-CA is an effective drug carrier system for the topical administration of C.sinensis extract for the treatment of acne.

Boric acid-functionalized silver nanoparticles as SERS substrate for sensitive and rapid detection of fructose in artificial urine

The accurate detection of fructose in human urine can help prevent and screen for diseases such as fructokinase deficiency and hereditary fructose intolerance. Surface-enhanced Raman spectroscopy (SERS) is an analytical technique with selectivity and high sensitivity, which has been widely applied to the detection of targets with complex backgrounds. In this work, 4-mercaptophenylboronic acid (4-MPBA) was modified on the surface of silver nanoparticles (AgNPs) under mild conditions to obtain a boronic acid-functionalized SERS substrate for the detection of fructose in artificial urine. The detection mechanism was based on the deboronization reaction of 4-MPBA on the surface of AgNPs, which was induced by fructose, and the Raman signal of the generated thiophenol (TP) molecules was significantly enhanced by the silver nanoparticles, with a linear increase in SERS peak intensity at 1570 cm−1. We achieved the detection limits of 0.084 µmol/L in water and 0.535 µmol/L in urine by this method. The relative standard deviation (RSD) in the recovery experiments of urine ranged from 1.01 % to 2.22 %, and the whole detection time was less than 10 min, which indicated that this method is highly reliable for fructose detection and has a good prospect in bioassay and clinical medicine.

Synthesis and Characterization of 1H-Imidazole-4,5-dicarboxylic Acid-Functionalized Silver Nanoparticles: Dual Colorimetric Sensors of Zn2+ and Homocysteine.

A colorimetric assay has been developed for Zn2+ and homocysteine (Hcy) detection using functionalized silver nanoparticles (AgNPs). AgNPs have been synthesized using silver nitrate, where sodium citrate is used as a stabilizing agent and NaBH4 as a reducing agent. Then, the nanoparticles (citrate@AgNPs) were functionalized with 1H-imidazole-4,5-dicarboxylic acid (IDCA). UV–visible and FTIR spectra suggested that IDCA was functionalized on the surface of citrate@AgNPs through the N atom of the imidazole ring. The IDCA-functionalized silver nanoparticles (IDCA@AgNPs) simultaneously detected Zn2+ and Hcy from aqueous solution and showed different responses to the two analytes (Zn2+ and Hcy) based on the aggregation-induced color change of IDCA@AgNPs. They showed the color change from yellow to red, which was easily discriminated by visual inspection as well as UV–visible spectroscopy. The surface plasmon resonance absorbance values of Zn2+ and Hcy are 485 and 512 nm, respectively, when Zn2+ and Hcy react with IDCA@AgNPs. IDCA@AgNPs showed linearity with Zn2+ and Hcy concentrations, with the detection limit of 2.38 μM and 0.54 nM, respectively (S/N = 3). The IDCA@AgNPs showed excellent selectivity toward Zn2+ and Hcy compared to the different metal ions and amino acids, respectively. Optimal detection was achieved toward Zn2+ and Hcy in the pH range 3–10. In addition, IDCA@AgNPs were used to detect Zn2+ and Hcy from lake water, showing low interference.

Highly sensitive electrochemical detection of biotin-avidin interaction on gold electrode modified with silver nanoparticles through bilayer assembly

The trifunctional l-cysteine containing carboxylic acid, amine and thiol is chemisorbed on the gold electrode surface via the thiol groups to form the self-assembled monolayer. Then the bilayer is assembled stepwise on the cysteine modified gold electrode. A layer of 3-marcaptopropionic acid functionalized silver nanoparticles is covalently coupled with amine group of cysteine and other layer of amine functional group containing biotin or avidin molecules is covalently coupled with carboxylic acid functional groups of cysteine. The improvement of electrochemical properties are noted for the cysteine modified gold electrode coupled with biomolecules first followed by coupling with the functionalized silver nanoparticles. This modified gold electrode is used to study the electrochemical sensing response of respective complementary biomolecule immobilized gold electrode towards the biotin or avidin. As revealed the avidin modified electrode is found to have better sensing performances toward biotin in terms of sensitivity and detection limit over the other one. The sensitivity of 1.243 Ω (ng)-1 L mm-2 and detection limit of 1.4 × 10−3 ng/L is observed for avidin sensing on biotin layer. For biotin sensing on avidin layer a sensitivity of 6.143 Ω (ng)-1 L mm-2 and detection limit of 1.2 × 10−5 ng/L is obtained from the calibration plot.

Phenylboronic acid-functionalized silver nanoparticles for highly efficient and selective bacterial killing.

With the widespread use of antibiotics, the number of severe infections caused by unknown pathogens is increasing and novel antibacterial agents with high antibacterial efficiency and selective bacterial killing are urgently needed. In this work, we developed a new kind of functional material based on silver nanoparticles (AgNPs), whose surfaces were functionalized with phenylboronic acid (AgNPs-PBAn). The phenylboronic acid groups on the surface of AgNPs-PBAn could form covalent bonds with the cis-diol groups of lipopolysaccharide or teichoic acid on the bacterial surface, which highly promoted the interaction between AgNPs-PBAn and bacteria, resulting in a very strong enhancement of their antibacterial action via membrane disruption. The scanning electron microscopy images revealed that the accumulation of phenylboronic acid-functionalized AgNPs on the bacterial surface is much more than that of the nonfunctionalized AgNPs. Importantly, the antibacterial efficiency of the phenylboronic acid-functionalized AgNPs on a series of bacteria is 32 times higher than that of bare AgNPs. Moreover, AgNPs-PBAn showed a high selectivity toward bacteria with an IC50 (half maximal inhibitory concentration to mammalian cells) more than 160 times its MBC (minimum bactericidal concentration). In a model of an E. coli-infected wound in vivo, AgNPs-PBAn could effectively kill the bacteria with an accelerated wound healing rate. This study demonstrates that phenylboronic acid surface functionalization is an efficient way to drastically promote the antibacterial activity of AgNPs, improving the selectivity of silver-based nanoparticles against a variety of bacteria.

Determination of Chromium(VI), Chromium(III), Arsenic(V), Aluminum(III), Iron(II), and Manganese(II) by Colorimetry and Surface-Enhanced Raman Scattering (SERS) Using Ferulic Acid Functionalized Silver Nanoparticles

Plasmonic nanoparticles having localized surface plasmon resonance in the visible and infrared region are potential candidates for the fabrication of simple, rapid, selective and specific metal ion detection systems based on colorimetry and surface-enhanced Raman spectroscopy. The study describes simple approaches for selective colorimetric and surface-enhanced Raman scattering determination of aluminum(III), chromium (VI), chromiun(III), manganese (II), iron(II) and arsenic (V) ions in aqueous medium using ferulic acid functionalized silver nanoparticles (F-AgNPs) synthesized by chemical reduction and microwave assisted method. The analysis of photographs reveals that ferulic acid functionalized silver nanoparticles synthesized by chemical reduction (C-F-AgNPs) sensitively detect Al(III) ions in aqueous media while nanoparticles synthesized by microwave reduction method can be used to determine As(V), Mn(II) and Fe(II) ions. In addition, C-F-AgNPs also enhance the Raman spectral profile of the water samples spiked by Cr(III) ions giving a peculiar vibration spectral feature that assists in the detection of Cr(III) ion in aqueous medium. Moreover, ferulic acid functionalized silver nanoparticles synthesized by the microwave assisted method (M-F-AgNPs) increase the intensity of Raman bands in the spectral profile of the water samples spiked with Cr(VI) and Mn(II) ions. The specific and selective interactions of F-AgNPs with the Cr(VI), Cr(III), Mn(II), Fe(II), Al(III) and As(V) leading to the aggregation of the dispersed silver nanoparticles enable their determination in aqueous media . The results of the present study shows the potential of F-AgNPs based sensor probes toward conceptualizing and fabricating simple, rapid and cost effective detection tools onsite determination of metal ions in aqueous media.

Biodegradable hydrogel with thermo-response and hemostatic effect for photothermal enhanced anti-infective therapy

Massive bleeding and infectious complication remain the leading cause of worldwide trauma deaths. To tackle this issue, a platelet-inspired degradable antibacterial hydrogel (Gel/PP-TA-Ag) is synthesized based on gelatin methacrylate (GelMA), tannic acid (TA), polyphosphate (PolyP) and gallic acid functionalized silver nanoparticles (Ag NPs) via a facile photopolymerization process. Accompanied by the degradation of the hydrogel, the released PolyP can activate the coagulation pathway, resulting in a better hemostatic effect than commercial gauze in the mice-bleeding model. Simultaneously, benefiting from hyperthermia originated from Ag NPs and photothermal accelerated release of TA and Ag+, 97.57% of methicillin-resistant Staphylococcus aureus (MRSA) and 95.99% of E. coli are eliminated in vitro. Moreover, in vivo experiments reveal that 91.76% of MRSA in wounds is removed, and the wound healing is effectively improved with more angiogenesis and collagen deposition. The level of inflammation in the wounds is also significantly reduced. As a result, Gel/PP-TA-Ag hydrogel possesses great potential in achieving satisfactory efficacy in infected wound healing.

Glycolic acid functionalized silver nanoparticles: A novel approach towards generation of effective antibacterial agent against skin infections

Recent years have witnessed that silver nanoparticles have demonstrated an efficient and broad range of antimicrobial activity in proportion to other metal nanoparticles. Herein, we report the synthesis of biocompatible silver nanoparticles by using glycolic acid (GA-AgNPs) as a capping and reducing agent and their application as antimicrobial agents against skin cancer cells. GA-AgNPs were further characterized using UV–visible, transmission electron microscopy, fourier transform infrared spectroscopy, proton-nuclear magnetic resonance, dynamic light scattering and zeta potential. Further, in order to assess their antibacterial potential, the synthesized nanoparticles were tested against Gram-positive and Gram-negative bacterial strains. The results revealed that synthesized GA-AgNPs were very active against the tested Gram-negative as well as Gram-positive pathogens. Also, the ion release study was performed using inductively coupled plasma-mass spectrometry. Further, in order to check their biocompatibility, cytotoxicity studies of the AgNPs were performed against skin cell lines (HaCaT) and these were found to be relatively non-toxic. This study, therefore, opened a new pathway for further applications of GA-AgNPs in targeting skin infections and fighting multi drug resistance.

Electrochemical sensing by a covalently bonded biotin–avidin couple on a silver nanoparticle modified gold electrode

A gold electrode was modified with cysteamine by a self-assembly monolayer technique and covalently coupled with 3-mercaptopropionic acid functionalized silver nanoparticles. The free carboxylic acid groups of the 3-mercaptopropionic acid functionalized silver nanoparticles assembled on gold electrode were bonded with the amine groups of biotin or avidin trough amide linkages. The changes in the interfacial properties of gold electrode modified stepwise were examined by cyclic voltammetry and electrochemical impedance spectroscopy using the ferric/ferrous redox system. The electrochemical sensing properties of covalently bonded biotin or avidin on a gold electrode modified with silver nanoparticle were studied by cyclic voltammetry and electrochemical impedance spectroscopy by the varying concentrations of the bio-affinity molecules in the same redox system. The charge transfer resistance was directly proportional to the concentration of analyte while the response was weakly dependent upon the change in the respective peak anodic currents. The sensing mechanism was established to explain the role of the silver nanoparticles.

Synthesis Of PEG Coated Ascorbic Acid Functionalized Silver Nanoparticles and Determining its Antioxidant Activity

Silver nanoparticles are extensively being studied for various applications in different fields. Functionalized silver nanoparticles are now being used as drug carriers. Ascorbic acid (Vitamin C) is a well-known antioxidant which has been reported to have various beneficial properties to humans. Here we have synthesized silver nanoparticles functionalized with ascorbic acid. The functionalized nanoparticles were further coated with PEG. The nanoparticle synthesis was characterized using UV-Visible spectral analysis, XRD, FTIR and Scanning electron microscope. The average size of the nanoparticle was found to be 24 nm. The synthesized nanoparticle was found to possess antioxidative effects.

Gallic acid-functionalized silver nanoparticles as colorimetric and spectrophotometric probe for detection of Al3+ in aqueous medium

Metal chelation-enhanced changes in surface plasmon resonance (SPR) band of gallic acid-functionalized AgNP solution to monitor aluminum ions (Al3+) is reported herein. In aqueous solution, Al3+ selectively induced a strong absorbance with large shifts up to ∼125nm from the SPR band with color changing from orange to red. This study illustrates that hydroxyl groups of phenol affect the response of a probe that tunes the absorbance maxima to a longer wavelength at 525nm. Moreover, the rapid formation of a AgNP-Al3+ coordination complex was demonstrated by real-time monitoring, adsorptive removal, and energy dispersive spectroscopy mapping.

Alpha-Lipoic Acid Functionalized Silver Nanoparticles for Colorimetric Detection of Copper Ion.

A facile, low cost, rapid and easy-to-use colorimetric sensor for the detection of Cu2+ ion is described using alpha-lipoic acid (ALA) functionalized AgNPs. The prepared ALA-AgNPs are yellow, and spherical with an average particle size of 9.23 ± 3.36 nm. The addition of Cu2+ ion resulted in the aggregation of ALA-AgNP solution and caused a visible color change from yellow to orange-brown, which could be detected by the naked eye and UV-vis spectrophotometer. Parameters affecting the sensitivity of the sensor were investigated, including ALA concentrations, reaction times, reaction volumes and pH. Under optimal conditions, the colorimetric sensor could detect Cu2+ ion in the range of 0.625 × 10-5 to 10 × 10-5 M with a linear coefficient (r) of 0.9978. The limit of detection (LOD) and limit of quantification (LOQ) were 0.43 × 10-5 M (4.3 μM) and 1.45 × 10-5 M (14.5 μM), respectively, which is lower than the limit set by the U.S. Environmental Protection Agency (EPA). This proposed method showed good selectivity and could detect Cu2+ within 5 min. Finally, the proposed method could be successfully applied for the analysis of Cu2+ ion in tap water samples.

A simple, rapid and cost-effective colorimetric assay based on the 4-mercaptophenylboronic acid functionalized silver nanoparticles for bacteria monitoring

The rapid and cost- effective detection of bacteria is of great importance in various fields. Herein, a novel colorimetric detection method for Gram-negative bacteria based on the inhibition of the aggregation of 4-mercaptophenylboronic acid functionalized AgNPs (MPBA-AgNPs) was demonstrated. MPBA, one of the boronic acid derivative, which could react with the cis-diol groups contained in saccharides on the bacteria cells, was used as the recognition molecule for bacteria detection. The aggregation of MPBA-AgNPs could be inhibited by bacterial cells, resulting in different color change, which could be distinguished with UV–vis spectrometer and the naked eye. The concentration of E. coli, a model of Gram-negative bacteria, could be determined in a dynamic range from 5 × 104 cfu mL−1 to 1 × 107 cfu mL−1 with a LOD of 0.9 × 104 cfu mL−1 with fast response of 20 min. Meanwhile, a smartphone based measuring analysis was established to make it suitable for routine laboratory applications. Moreover, the concept of the MPBA-AgNPs based colorimetric strategy could be expanded to other Gram-negative bacteria suggesting a universal platform for bacterial assay.

Biosynthesis of amino acid functionalized silver nanoparticles for potential catalytic and oxygen sensing applications

A green approach to the biosynthesis of amino acid functionalized silver nanoparticles (AgNPs) using Neem gum is reported herein.