Green synthesis of silver nanoparticles using Nervalia zeylanica leaf extract and evaluation of their antioxidant,catalytic, and antimicrobial potentials

ABSTRACT

Here we report a simple, one-pot, inexpensive, and eco-friendly method for the synthesis of silver nanoparticles. The leaf extract of a medicinal plant Nervalia zeylanica was used as reducing and stabilizing agent for the synthesis of nanoparticles by microwave-assisted strategy. The nanoparticles show characteristic surface plasmon peak at 468?nm in UV–vis absorption spectrum. The involvement of phytochemicals in the reduction and stabilization of nanoparticles was confirmed by FTIR analysis. Using X-ray diffraction analysis, the crystalline nature of the nanoparticles was demonstrated. Transmission electron microscopic analysis shows that the nanoparticles were in spherical shape with average particle size of 34.2?nm. The antioxidant studies were performed by the 1,1-diphenyl-2-picryl hydrazyl method. The nanoparticles show excellent scavenging activities than the leaf extract. The IC₅₀ values of silver nanoparticles and the leaf extract, respectively, were 15.20 and 92.83?µg?mL^?1. The catalytic activities of synthesized nanoparticles were examined by using them in the reduction of organic dyes. The nanoparticles show excellent catalytic activities and follow pseudo-first-order kinetics. The antimicrobial activities of nanoparticles were analyzed by an agar well diffusion method against six microbial strains and found that the nanoparticles were highly toxic against all the tested microbial strains.     

Magnetic nanobeads decorated with silver nanoparticles as cytotoxic agents and photothermal probes

A versatile method for decorating magnetic nanobeads (being composite materials from polymers and superparamagnetic nanoparticles) with silver nanoparticles of 3-6 nm size is presented. Control over the silver nanoparticle coverage at the nanobead surface is achieved by changing the reaction parameters. Moreover, the silver-decorated magnetic nanobeads (Ag-MNBs) are studied with respect to their in vitro cytotoxicity on two distinct tumour cell lineages under different parameters, i.e., dose, incubation time, magnetic field applied during the culturing, silver ion leakage, and colloidal stability. It is found that enhanced magnetically mediated cellular uptake and silver ion leakage from the Ag-MNBs surface are the main factors which affect the toxicity of the Ag-MNBs and allow the half-maximal inhibitory dose of silver to be reduced to only 32 μg mL(-1) . Furthermore, a synergic cytotoxicity induced by photo-activation of silver nanoparticles was also found.     

Synthesis and characterization of silver nanoparticles and their antimicrobial efficacy

An efficient protocol for synthesis of silver nanoparticles (AgNPs) using the combination of aqueous extract of Tinospora cordifolia leaves and 5 mM silver nitrate (AgNO₃) solution was developed. This study revealed that bioactive compounds present in the extract function as stabilizing and capping agent for AgNPs. Scanning electron microscope and transmission electron microscope studies confirm the structure and surface morphology of the AgNPs. The size of synthesized AgNPs was in the range of 30–50 nm having spherical morphology. The crystalline nature of NPs was defined by the X-ray diffraction pattern. The AgNPs were found to be toxic against pathogenic bacteria such as Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Staphylococcus aureus (ATCC 29213) and against plant pathogenic fungi Fusarium oxysporum (MTCC 8608) and Sclerotinia sclerotiorum (MTCC 8785). The use of AgNPs as antibacterial and antifungal agent is advantageous over other methods for control of pathogenic microorganisms, and it can be of great importance in developing novel drugs for curing many lethal diseases.     

A novel approach for the biosynthesis of silver oxide nanoparticles using aqueous leaf extract of Callistemon lanceolatus (Myrtaceae) and their therapeutic potential

This study describes a novel biological route for the biosynthesis of silver oxide nanoparticles utilising the aqueous extract of Callistemon lanceolatus D.C. leaves. Formation of silver oxide nanoparticles was confirmed by UV–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscope–energy dispersive X-ray spectroscopy and X-ray diffraction spectroscopy analysis. The biologically synthesised silver oxide nanoparticles were found to be 3–30 nm in size with spherical and hexagonal shape by high-resolution transmission electron microscope analysis. Furthermore, the biogenic silver oxide nanoparticles demonstrated significant (p?in vitro antioxidant methods. These particles also exhibited significant (p?相似文献   

Biosynthesis of silver nanoparticles in collagen gel improves their medical use in periodontitis treatment

Silver nanoparticles (AgNP) suspensions were biosynthesized by silver ions reduction in the presence of collagen, a nontoxic, organic polymer, intending to improve their medical use in periodontitis treatment. Spectrophotometric measurements showed a time- and concentration-dependent increase of AgNP formation in each suspension variant. Transmission electron microscopy revealed spherical morphology of AgNP in collagen and their mean diameter size was around 30?nm. The particle size distribution and zeta potential values of AgNP in collagen were determined by dynamic light scattering measurements. The surface charge of AgNP in collagen was positive, while commercial AgNP stabilized in citrate had negative surface charge. In vitro cytotoxicity testing of AgNP in collagen showed that they were biocompatible with human gingival fibroblasts in a wider range of concentrations than commercial nanoparticles. The antibacterial activity of AgNP in collagen against two pathogenic strains present in the periodontal pocket was dose-dependent and higher than that of AgNP in citrate. All these results demonstrated that AgNP prepared in collagen gel had improved properties, like small diameter, positive surface charge, high biocompatibility in human gingival fibroblasts, efficiency against bacterial growth and, thus, better therapeutic potential in periodontal disease treatment.     

葡聚糖包被磁性纳米材料的合成及其特异性细胞毒性

利用二甘醇作溶剂和还原剂水解还原三氯化铁,合成水溶性的葡聚糖包被磁性纳米材料(MNPs),选择大鼠的肝脏细胞BRL3A、肾脏细胞NRK、星型角质细胞和外周血单个核细胞(PBMC),运用流式细胞仪(FCM)检测细胞凋亡和苏木素伊红(HE)染色细胞形态学观察进行细胞毒性研究.结果发现,MNPs共培养浓度达到64μg/ml时,PBMC出现明显凋亡(p＜0.01),而其它几种细胞在MNPs共培养浓度达到128μg/ml时,仍未出现明显凋亡(p＞0.05).电镜观察发现BRL3A、NRK和星型角质细胞均出现内吞该纳米颗粒,而未观察到PBMC的吞噬现象.结果提示,葡聚糖包被的MNPs的细胞毒性具有细胞特异性,实质性脏器细胞毒性较小,可能与其存在内吞MNPs能力有关,提示葡聚糖包被的MNPs可以运用于机体实质脏器核磁造影剂和药物载体.     

Green synthesis of silver nanoparticles using biopolymers,carboxymethylated-curdlan and fucoidan

There is a growing need in developing a reliable and eco-friendly methodology for the synthesis of metallic nanoparticles, which may be applied for many nanotechnological applications. Natural compounds such as biopolymers are one of the resources which could be used for this purpose. The present study involves the development of a simple, ecological and user-friendly method in synthesizing silver nanoparticles by using carboxymethylated-curdlan or fucoidan as reducing and stabilizing agents. Reduction of silver ions by these biopolymers occurred when heating at 100 °C, led to the formation of silver nanoparticles in the range of 40–80 nm in dimensions. The silver nanoparticles were formed readily within 10–15 min. Morphological observation and characterization of the silver nanoparticles were performed by using dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and UV–vis absorption spectrophotometer. The size of silver nanoparticles can be controlled by using different concentrations of carboxymethylated-curdlan, fucoidan or silver nitrate. This way of silver nanoparticles preparation is easy, fast, user-friendly and suitable for large-scale production.     

Medicinal plants mediated the green synthesis of silver nanoparticles and their biomedical applications

The alarming effect of antibiotic resistance prompted the search for alternative medicine to resolve the microbial resistance conflict. Over the last two decades, scientists have become increasingly interested in metallic nanoparticles to discover their new dimensions. Green nano synthesis is a rapidly expanding field of interest in nanotechnology due to its feasibility, low toxicity, eco‐friendly nature, and long‐term viability. Some plants have long been used in medicine because they contain a variety of bioactive compounds. Silver has long been known for its antibacterial properties. Silver nanoparticles have taken a special place among other metal nanoparticles. Silver nanotechnology has a big impact on medical applications like bio‐coating, novel antimicrobial agents, and drug delivery systems. This review aims to provide a comprehensive understanding of the pharmaceutical qualities of medicinal plants, as well as a convenient guideline for plant‐based silver nanoparticles and their antimicrobial activity.     

Green synthesis of silver nanoparticles using flower extract of Malva sylvestris and investigation of their antibacterial activity

High‐quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of Malva sylvestris. Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20–40 nm. The antibacterial activity of the synthesised nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract.Inspec keywords: silver, nanoparticles, nanofabrication, antibacterial activity, colloids, particle size, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, microorganisms, nanomedicine, biomedical materialsOther keywords: Green synthesis, flower extract, Malva sylvestris, antibacterial activity, high‐quality colloidal silver nanoparticles, hydroalcoholic extracts, plant extract, reducing agents, stabilising agents, transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, UV– vis spectroscopy, colloidal solutions, particle size distribution, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, disk diffusion, minimum inhibitory concentrations, minimum bactericidal concentrations assays, ethanolic extract, size 430 nm, size 485 nm, size 504 nm, size 20 nm to 40 nm, Ag     

Eco-friendly green synthesis of silver nanoparticles and their potential applications as antioxidant and anticancer agents

Abstract

Eco-friendly green synthesis of nanoparticles using medicinal plants gained immense importance due to its potential therapeutic uses. In the current study, silver nanoparticles (AgNPs) were synthesized using water extract of Jurinea dolomiaea leaf and root at room temperature. MTT assay was used to study anticancer potential of AgNPs against cervical cancer cell line (HeLa), breast cancer cell lines (MCF-7), and mouse embryonic fibroblast (NIH-3 T3) cell line for toxicity evaluation. The antioxidant potential was evaluated using stable DPPH radicals. In addition, the apoptotic nuclear changes prompted by AgNPs in more susceptible HeLa cells were observed using fluorescence microscope through DAPI and PI staining. Physiochemical properties of biosynthesized AgNPs were characterized using various techniques. AgNPs were formed in very short time and UV–vis spectra showed characteristic absorption peak of AgNPs. SEM and TEM showed spherical shape of AgNPs and XRD revealed their crystalline nature. EDX analysis revealed high percentage of silver in green synthesized AgNPs. FTIR analysis indicated involvement of secondary metabolites in fabrication of AgNPs. In vitro cytotoxic and antioxidant study revealed that herb and biosynthesized AgNPs exhibited significant dose-dependent and time-dependent anticancer and antioxidant potential. Furthermore, study on normal cell line and microscopic analysis of apoptosis revealed that AgNPs exhibited good safety profile as compared to cisplatin and induces significant apoptosis effect. Based on the current findings, it is strongly believe that use of J. dolomiaea offers large scale production of biocompatible AgNPs that can be used as alternative anticancer agents against cancer cell lines tested.     

Green synthesis of silver nanoparticles using Mentha pulegium and investigation of their antibacterial,antifungal and anticancer activity

A simple and eco‐friendly method for efficient synthesis of stable colloidal silver nanoparticles (AgNPs) using Mentha pulegium extracts is described. A series of reactions was conducted using different types and concentrations of plant extract as well as metal ions to optimize the reaction conditions. AgNPs were characterized by using UV–vis spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering, zetasizer, energy‐dispersive X‐ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR). At the optimized conditions, plate shaped AgNPs with zeta potential value of ‐15.7 and plasmon absorption maximum at 450 nm were obtained using high concentration of aqueous extract. Efficient adsorption of organic compounds on the nanoparticles was confirmed by FTIR and EDAX. The biogenic AgNPs displayed promising antibacterial activity on Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes. The highest antibacterial activity of 25 µg mL‐1 was obtained for all the strains using aqueous extract synthesized AgNPs. The aqueous extract synthesised AgNPs also showed considerable antifungal activity against fluconazole resistant Candida albicans. The cytotoxicity assay revealed considerable anticancer activity of AgNPs on HeLa and MCF‐7 cancer cells. Overall results indicated high potential of M. pulegium extract to synthesis high quality AgNPs for biomedical applications.Inspec keywords: silver, nanoparticles, nanofabrication, botany, antibacterial activity, biomedical materials, nanomedicine, ultraviolet spectra, visible spectra, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform infrared spectra, electrokinetic effects, microorganisms, cellular biophysics, cancerOther keywords: antibacterial activity, antifungal activity, anticancer activity, stable colloidal silver nanoparticle, Mentha pulegium, plant extract, UV‐visible spectroscopy, transmission electron microscopy, atomic force microscopy, DLS, zetasizer, energy‐dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, methanolic extract, aqueous extract, plate‐shaped silver nanoparticle, zeta potential, plasmon absorption maximum, organic compounds adsorption, biogenic silver nanoparticle, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, fluconazole‐resistant Candida albicans, MTT assay, HeLa cancer cell, MCF‐7 cancer cell, Ag     

Preparation and characterisation of ciprofloxacin‐loaded silver nanoparticles for drug delivery

Silver nanoparticles (AgNPs) have shown potential applications in drug delivery. In this study, the AgNPs was prepared from silver nitrate in the presence of alginate as a capping agent. The ciprofloxacin (Cipro) was loaded on the surface of AgNPs to produce Cipro‐AgNPs nanocomposite. The characteristics of the Cipro‐AgNPs nanocomposite were studied by X‐ray diffraction (XRD), UV–Vis, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier‐transform infra‐red analysis (FT‐IR) and zeta potential analyses. The XRD of AgNPs and Cipro‐AgNPs nanocomposite data showed that both have a crystalline structure in nature. The FT‐IR data indicate that the AgNPs have been wrapped by the alginate and loaded with the Cipro drug. The TEM image showed that the Cipro‐AgNPs nanocomposites have an average size of 96 nm with a spherical shape. The SEM image for AgNPs and Cipro‐AgNPs nanocomposites confirmed the needle‐lumpy shape. The zeta potential for Cipro‐AgNPs nanocomposites exhibited a positive charge with a value of 6.5 mV. The TGA for Cipro‐AgNPs nanocomposites showed loss of 79.7% in total mass compared to 57.6% for AgNPs which is due to the Cipro loaded in the AgNPs. The release of Cipro from Cipro‐AgNPs nanocomposites showed slow release properties which reached 98% release within 750 min, and followed the Hixson–Crowell kinetic model. In addition, the toxicity of AgNPs and Cipro‐AgNPs nanocomposites was evaluated using normal (3T3) cell line. The present work suggests that Cipro‐AgNPs are suitable for drug delivery.     

含纳米银的明胶/壳聚糖纳米纤维的制备及其抗菌性能研究

以浓度为88%的甲酸溶液作为纺丝溶剂,采用静电纺丝和紫外光照射还原的方法制备了含纳米银颗粒的明胶/壳聚糖纳米纤维。研究发现,壳聚糖的加入量低于明胶质量的3/16时可以得到纳米纤维,纤维平均直径随着硝酸银加入量的增大而减小,纤维表面纳米银的平均直径随着硝酸银加入量的增大而增大,在纺丝体系中硝酸银的加入量存在一个极限值。所制得含纳米银的明胶/壳聚糖纳米纤维对金黄色葡萄球菌和绿脓杆菌具有较好的抑菌性能,纺丝时加入1%硝酸银制得纳米纤维膜的抑菌率达到99%以上,这种抗菌型纳米纤维可以应用于医用敷料等领域。     

Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium semitectum

Development of environmental friendly procedures for the synthesis of metal nanoparticles through biological processes is evolving into an important branch of nanobiotechnology. In this paper, we report on the use of fungus “Fusarium semitectum” for the extracellular synthesis of silver nanoparticles from silver nitrate solution (i.e. through the reduction of Ag⁺ to Ag⁰). Highly stable and crystalline silver nanoparticles are produced in solution by treating the filtrate of the fungus F. semitectum with the aqueous silver nitrate solution. The formations of nanoparticles are understood from the UV-vis and X-ray diffraction studies. Transmission electron microscopy of the silver particles indicated that they ranged in size from 10 to 60 nm and are mostly spherical in shape. Interestingly the colloidal suspensions of silver nanoparticles are stable for many weeks. Possible medicinal applications of these silver nanoparticles are envisaged.     

Synthesis and characterisation of cross-linked chitosan composites functionalised with silver and gold nanoparticles for antimicrobial applications

Abstract

We present a study of a range of cross-linked chitosan composites with potential antimicrobial applications. They were formed by cross-linking chitosan and siloxane networks and by introducing silver and gold nanoparticles (NPs). The aim was to investigate whether adding the metal NPs to the chitosan-siloxane composite would lead to a material with enhanced antimicrobial ability as compared to chitosan itself. The composites were synthesised in hydrogel form with the metal NPs embedded in the cross-linked chitosan network. Spectroscopic and microscopic techniques were employed to investigate the structural properties of the composite and the tensile strength of the structures was measured. It was found that the addition of metal NPs did not influence the mechanical strength of the composite. A crystal violet attachment assay results displayed a significant reduction in the attachment of E. coli to the cross-linked chitosan surfaces. Release profile tests suggest that the metal NPs do not contribute to the overall antimicrobial activity under neutral conditions. The contribution to the mechanical and antimicrobial properties from cross-linking with siloxane is significant, giving rise to a versatile, durable, antimicrobial material suitable for thin film formation, wound dressings or the coating of various surfaces where robustness and antimicrobial control are required.     

Green synthesis of silver nanoparticles from purple acid phosphatase apoenzyme isolated from a new source Limonia acidissima

Green synthesis of nanoparticles is regarded as a safe and non-toxic process whereas conventional synthesis using chemical methods produces toxic substance. This study provides a novel insight for enzymatic synthesis method of silver nanoparticles using purple acid phosphatase, isolated from Limonia acidissima (wood apple) as a new source and used in the synthesis of silver nanoparticles. Stable silver nanoparticles were produced by sonochemical method using apoenzyme as a stabilising and capping agent and were characterised by various physicochemical techniques like UV–Visible spectroscopy, Fourier-transform infrared, X-ray diffraction and transmission electron microscopy. X-ray study shows that nanoparticles are composed of silver and silver oxide. The synthesised nanoparticles exhibited excellent antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.     

Characterization of phyto-nanoparticles from Ficus krishnae for their antibacterial and anticancer activities

Background: Ovarian cancer is deadliest of fifth leading cause of death in women worldwide. This is due to advanced-stage disease rate associated with the development of chemoresistance. Hence, the current study emphasizes the process of synthesis of silver nanoparticles (AgNPs) from green chemistry method. Ficus krishnae is a perennial plant, native to India, used in folklore medicine to treat various diseases.

Objective: For the development of reliable, ecofriendly, less expensive process for the synthesis of AgNPs against bacterial and ovarian cancer.

Methodology: The synthesis of silver nanoparticles from stem bark of Ficus krishnae was carried out. The synthesized nanoparticles are subjected by UV-Vis spectrophotometer, scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and FTIR analysis. The antibacterial efficacy also determined by disc diffusion method, MIC, CFU and growth curve. In vitro cytotoxicity effect of aqueous extract and AgFK nanoparticle in ovarian cancer cell line by MTT assay was performed.

Results: The formation of AgNPs was confirmed by UV-VIS spectroscopic absorbance shown that peak at 435?nm. XRD photograph has indicated the face-centered cubic structure of the synthesized AgNPs. SEM study demonstrated that the size from 160 to 260?nm with interparticle distance, whereas shape is spherical. The particle size were ranging from 15 to 28?nm determined by XRD pattern. The antibacterial and cytotoxicity activity of this nanoparticle has showed a potential activity when compared with standards.

Conclusion: The present study confirms that the biosynthesized AgNPs from Ficus krishnae stem bark extract have a great affiance as antibacterial and anticancer agent.     

Green synthesis of silver nanoparticles using Zea mays and exploration of its biological applications

The biosynthesis of silver nanoparticles (AgNPs) has been proved to be a cost effective and environmental friendly approach toward chemical and physical methods. In the present study, biosynthesis of AgNPs was carried out using aqueous extract of Zea mays (Zm) husk. The initial colour change from golden yellow to orange was observed between 410 and 450 nm which confirmed the synthesis of AgNPs. Also, dynamic light scattering‐particle size analysis confirmed the average size to be 113 nm and zeta potential value of −28 kV. The morphology of synthesised Zm AgNPs displayed flower‐shaped structure, X‐ray diffraction pattern revealed the strongest peaks at 2θ = 38.6° and 64° which proved that the nanoparticle has the face centred crystalline structure. The Fourier transform infrared spectroscopy results showed strong absorption bands at 1394.53, 2980.02 and 2980.02 cm⁻¹ due to the presence of alkynes, carboxylic acids, alcoholic and phenolic groups. The maximum zone of inhibition was observed against Salmonella typhi (22 mm) and Candida albicans (18 mm). The synthesised nanoparticles exhibited more free radical scavenging activity than the aqueous plant extract. This is the first report on the synthesis of AgNP from Zm husk, delivers the efficient and stable Zm AgNPs through simple feasible approach toward green biotechnology.Inspec keywords: silver, nanoparticles, nanofabrication, light scattering, particle size, X‐ray diffraction, crystal structure, Fourier transform infrared spectra, absorption coefficients, free radicalsOther keywords: green synthesis, silver nanoparticles, biosynthesis, environmental friendly approach, aqueous extract, Zea mays husk, colour change, golden yellow, dynamic light scattering‐particle size analysis, average size, zeta potential value, flower‐shaped structure, X‐ray diffraction pattern, face centred crystalline structure, Fourier transform infrared spectroscopy, absorption bands, alkynes, carboxylic acids, alcoholic groups, phenolic groups, Salmonella typhi, Candida albicans, free radical scavenging activity, aqueous plant extraction, green biotechnology, size 113 nm, wavelength 410 nm to 450 nm     

Green synthesis of colloidal silver nanoparticles by sonochemical method

A facile sonochemical method was developed for preparing colloidal silver nanoparticles (Ag-NPs) in aqueous gelatin solutions. The effect of the reducing agent and Ag⁺ concentrations, ultrasonic time, and ultrasonic amplitude on the particle size has been investigated. The size of the Ag-NPs decreases with the ultrasonic amplitude and increases with ultrasonic time. Well-dispersed spherical Ag-NPs with a mean particle size of about 3.5 nm have been synthesized under ultrasonic process. The use of gelatin as an eco-friendly stabilizer provides green and economic attributes to this work. This preparation method is general and may be extended to other noble metals, such as Au, Pd and Pt, and may possibly find various additional medicinal, industrial and technological applications.     

Highly efficient in vitro biosynthesis of silver nanoparticles using Lysinibacillus sphaericus MR-1 and their characterization

Abstract

Silver nanoparticles (AgNPs) have been widely used in diverse fields due to their superior properties. Currently the biosynthesis of AgNPs is in the limelight of modern nanotechnology because of its green properties. However, relatively low yield and inefficiency diminish the prospect of applying these biosynthesized AgNPs. In this work, a rapid mass AgNP biosynthesis method using the cell-free extract of a novel bacterial strain, Lysinibacillus sphaericus MR-1, which has been isolated from a chemical fertilizer plant, is reported. In addition, the optimum synthesis conditions of AgNPs were investigated. The optimum pH, temperature, dosage, and reaction time were 12, 70 °C, 20 mM AgNO₃, and 75 min, respectively. Finally, AgNPs were characterized by optical absorption spectroscopy, zeta potential and size distribution analysis, x-ray diffraction, electron microscopy, and energy-dispersive x-ray spectroscopy. The results revealed that these biosynthesized AgNPs were bimolecular covered, stable, well-dispersed face centered cubic (fcc) spherical crystalline particles with diameters in the range 5–20 nm. The advantages of this approach are its simplicity, high efficiency, and eco-friendly and cost-effective features.