Properties, effects and chemical and biological method of synthesis of silver nanoparticles

 Corresponding author: VARUN RAVINDRA MALI ORCID ID: https://orcid.org/0009-0008-1072-7074 Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Properties, effects and chemical and biological method of synthesis of silver nanoparticles VARUN RAVINDRA MALI * Kishinchand Chellaram College, Churchgate, Mumbai-400020, India. World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 Publication history: Received on 07 January 2025; revised on 15 February 2025; accepted on 18 February 2025 Article DOI: https://doi.org/10.30574/wjbphs.2025.21.2.0197 Abstract The silver nanoparticles (AgNPs) have gained significant attention due to their remarkable properties. Due to the electrical and catalytic properties of silver nanoparticles it is greatly exploited commercially. However, silver nanoparticles adversely affect the environment and can have hazardous, detrimental toxic effects on mammals, nonmammals and plants. The properties of silver nanoparticles greatly depend on the synthesis process conditions such as process type, temperature, pH, concentration of precursor, reducing agents and capping agents used. In this review we have discussed the bottom-up approach which is categorized into chemical synthesis and green synthesis. The chemical synthesis is a conventional method which is used to synthesize silver nanoparticles. However, it does possess major disadvantages as compared to the green synthesis. The green synthesis has gained a significant interest among the researchers as an alternative route to effectively synthesize silver nanoparticles with varying morphology. Green synthesis methods such as viral-biotemplates synthesis using TMV has gained specific attention as it is used in the synthesis of 1D silver nanostructure. The advantages and disadvantages of bottom-up method of silver nanoparticle synthesis is also discussed. This article also provides a critical review on the properties and effects of silver nanostructures. Keywords: Silver; Silver nanoparticles; Toxicity in mammals; Toxicity in non-mammals; Toxicity in plants; Green synthesis 1. Introduction Metallic Silver (Ag) is the 67th abundant among the elements and is a durable transition element. Due to its rarity and attractive metallic luster silver has been used as jewelry, currency coins and other valuable items. In ancient times silver utensils were used to keep the water and wine clean. Silver finds its applications in medicine, as due to its antimicrobial activity silver is used as antibacterial, antiviral, and antifungal. In the 17th and 18th century Silve Nitrate (AgNO3) was applied to treat ulcers [1]. 1% Silver Nitrate was introduced as an eye solution to prevent conjunctivitis in small children [2]. Silver Sulfadiazine in its tropical form is used to treat burn wounds [3]. Besides all these applications, exposure to high concentration of silver for prolonged periods may result in deposition of silver in the body, which may further cause irreversible discoloration of skin and eyes, this condition is called Argyria [4]. Due to the hazards and high cost associated with silver its medical interest started diminishing around the mid1900s. Antibiotics like Penicillin and Cephalosporin started to replace the medicinal interest gained by silver due to its low cost and low risk associated with its usage. The interest of silver as medicinal drug was revived because of the largescale increase in the number of multiple drug-resistant bacteria which was the result of exploitation of antibacterials. Silver performed excellent due to its antimicrobial properties and when enhanced using Nanotechnology the limitation of silver in its pure state were overcome. These nano synthesized silver materials were having smaller size (in nm range) World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 477 which enhanced its surface area, that in turn improves its reactivity. AgNPs showed biocidal action by slowly releasing Ag+ that results in enhanced drug delivery and bioavailability. By using different mechanisms like interaction with Thiol groups in protein and enzymes, inducing Oxidative stress by generating ROS and inhibition of DNA replication; making it more difficult for the bacteria to produce drug resistant strains [5]. Due to their properties such as electrical properties [12-14], catalytic properties [15-18], antimicrobial properties [2430], surface plasmon resonance [14] and surface-enhanced reman scattering [19-23] the silver nanoparticles find wide spectrum of application. However, the AgNPs exhibits toxicity to mammals [39-42], non-mammals [44-49] and plants [50-55]. Generally, all silver nanoparticles including silver nanoparticles are synthesized by two approaches [57] namely topdown where nanoparticles are synthesized from the bulk material and bottom-up approach in which the nucleation sites are formed initially, and then grown into nanoparticles. The top-down method that consist of physical methods for the synthesis of AgNPs is not the scope of this review. This review only focuses on the bottom-up approach for the synthesis of silver nanostructures. The bottom-up method can be further categorized into Chemical synthesis which consist of Chemical reduction [56-59], Sol-Gel Method [60-67], Chemical Vapor deposition method [68-76], Reverse micelle process [77-83] , Wet chemical synthesis [84-94] and the Biological synthesis (Green synthesis ). The biological synthesis consists of two categories, Plant mediated synthesis of AgNPs [104-123] and Microbial-mediated synthesis which consist of Bacteriogenic synthesis [131-138], Algae-mediated synthesis [143-151], Fungi-mediated synthesis [153-158] and Virus-mediated synthesis [162-168] for the synthesis of AgNPs. Various studies have focused on the synthesis of AgNPs without considering the cost and hazards associated with it. For example, Hydrazine and NaBH4 which are commonly used as a strong reducing agent in many chemical methods of synthesizing AgNPs [85], is very toxic, carcinogenic chemical [86-88]. Due to the disadvantages associated with the chemical method green synthesis has observed more attention in recent years as the method is less detrimental and more cost-effective. However, there are still concerns regarding the stability, size distribution and morphology of the AgNPs produced by green synthesis [119], some biological methods cannot serve as a feasible option for industrial use as they are time consuming [157]. In this review, first we explain the properties and effect and in the second half of the article chemical and green synthesis of silver nanoparticles is discussed stating the application, advantages and disadvantages of the methods used to synthesize AgNPs. 2. Properties of Silver Nanoparticles 2.1. Electrical Properties Silver exhibits high thermal and electrical conductivity along with low contact resonance, making it a preferred choice in field of electronic. Silver nanoparticles find its application in Thin-Film transistor electrodes [12], conductive inks for printed circuit boards [13], data storage device and battery-based intercalation materials [14]. 2.2. Catalytic Properties Silver nanoparticles owing to their small size possess a high surface area, which translates into enhanced surface energy and numerous reactive sites. These features the AgNPs as a promising material in catalytic processes. AgNPs are effective in catalyzing CO and benzene oxidation [15], reduction of 4-nitrophenol in presence of NaBH4 [16]. Reduction of Rhodamine B (RhB) [17] and reducing 4-nitrophenol to 4-aminophenol [18]. Catalyzing CO: 𝑪𝑶 + 𝟏 𝟐 𝑶𝟐 𝑨𝒈𝑵𝑷𝒔 → CO2 This reaction has application in air purity and reducing toxic CO emissions. Catalyzing Benzene Oxidation: C6H6 + [O] 𝑨𝒈𝑵𝑷𝒔 → C6H5OH Oxidizing agents such as O2 or H2O2 World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 478 This reaction finds its application in Phenol production for chemical industry and degrading benzene in wastewater and polluted air. Catalyzing the reduction of RhB This reaction can be used to reduce the pollution caused by dye industries 2.3. Surface Plasmon Resonance (SPR) Silver nanoparticles (AgNPs) show unique properties distinct from their bulk metal counterpart. One such characteristic is to show Surface plasmon Resonance under irradiation of light. This phenomenon induces SPR peaks in UVvisible spectrum. Typically, the size, shape and dispersion of the nanoparticles influenced the width and position of SPR peaks [14]. 2.4. Surface-enhanced Raman scattering (SERS) A key application of AgNPs is their role in Surface-enhanced Raman scattering (SERS). AgNPs allows the detection and identification of single molecules by enhancing the efficiency of SERS by as much as 1014 to 1015 folds [19]. Due to these unique properties AgNPs have found its application in various fields, particularly sensing and imaging technologies. They are utilized in detecting DNA, where their plasmonic properties enable high sensitivity [20]. Additionally, AgNPs are employed in selective colorimetric sensing for biomolecules such as Cysteine [21], monitoring Purine nucleosides phosphorylase activity [22], and detecting environmental contaminants like Mercury [23]. 2.5. Antimicrobial Properties Silver when undergone nano synthesis showed excellent performance in antibacterial applications as it inhibits the growth of Gram-Positive and Gram-negative bacteria that includes Pseudomonas Aeruginosa, Escherichia Coli, and Staphylococcus Aures [24-25]. A study revealed that antimicrobial activity of many antibiotics was enhanced in the presence of silver nanoparticles (AgNPs) [26]. AgNPs is also used as antifungal and can kill fungal strains including Candida tropicalis, Aspergillus Fumigatus, Mucor and Saccharomyces Cerevisiae [27]. Nano silver synthesized in Hepes buffer (C8H18N2O4S) at pH 6.8 to 8.2 could inhibit HIV-1 replication and exhibit a much higher anti-HIV activity (98%) than gold nanoparticles (6-20%) [28]. Due to its antiviral properties, it is also used to inhibit Hepatitis B virus [29] and Herpes simplex virus [30]. 3. Effects of Silver Nanoparticles 3.1. Mechanism of Toxicity Numerous studies have been conducted to fully elucidate the mechanism of biocidal action of AgNPs, however no firm conclusion can be drawn so far. The antibacterial activity of AgNPs is complex process, and numerous modes of action are proposed, which involves: • Generation of Reactive oxygen Species (ROS): AgNPs are believed to induce the ROS production, ROS are unstable molecules that are derived from oxygen metabolism [31,32]. In cellular processes, normally ROS levels are regulated by antioxidant defenses. However, excessive ROS production overwhelms these defenses, leading World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 479 to oxidative stress. This oxidative stress may result in damaging vital cellular components, including lipids, proteins and nucleic acids, which disrupts cellular homeostasis [5,33]. • Attachment to the Cell membrane and Disruption of Membrane Integrity: AgNPs directly interacts with cell membrane leading to structural damage. This interaction compromises the integrity of the cell membrane, making it more permeable and susceptible to further damage. It is a critical factor in antibacterial efficacy of AgNPs[34]. • Alteration in Membrane Permeability: Changes in the permeability of cellular membrane is another consequence of AgNPs exposure. Changes like this can interfere with the cells ability to maintain a stable internal environment, which leads to a cascade of dysfunctions that can potentially impair cellular survival [35]. • Interaction with proteins and Disruption of their regular functions: AgNPs may bind to proteins, altering their structure and function. Proteins plays a vital role in a wide range of cellular processes, and their disruption can have significant downstream effects. For example, AgNPs may inhibit enzymes or other proteins that are essential for cellular metabolism and repair [36,37]. • DNA Damage and Disruption of Replication: Another important mechanism involves the interaction of AgNPs with DNA, leading to damaging and hindering replication process. DNA damage is particularly detrimental as it impairs the cell’s ability to divide and sustain itself that contributes to antimicrobial action of AgNPs [38]. 3.2. Toxicity to Mammals To date the available data on the effect of AgNPs in mammals in vivo is very less. The existing results have portrayed that AgNPs can cause toxicity to test animal model. This was studied by experimenting on Sprague-Dawley rats. In the first experiment Sprague-Dawley rats showed no significant changes in lungs and nasal cavity at a high dose of 1.32 X 106 particles cm-3 AgNPs in an inhalation chamber for 4 weeks. However, Goblet cells containing neutral mucin was affected and hence they increased in size and number. This suggest that AgNPs affects the neutral mucin in respiratory system [39]. In the second one, lung inflammation was reported. In this Sprague-Dawley rats undergoes inhalation exposure at a dose of 2.9 X 106 particles cm-3 for 6 hours per day this was done for 90 days (13 weeks). After 13 weeks, inflammation in the lungs was reported in rats, also the lung functional test showed significant decrease in tidal volume and minute volume. This experiment indicates that AgNPs may cause lung damage and affect their normal function [40]. No significant changes were observed in body weight, hematology and blood biochemistry for both male and female Sprague-Dawley rats after 4 weeks (28 days of exposure at high dose of 1.32 X 106 particles cm-3, implying that AgNPs having concentration near sliver dust (1X106 μ cm-3) did not produce any remarkable health effects on Sprague-Dawley rats [41]. A notable change in the values of alkaline Phosphatase and Cholesterol in both male and female Sprague-Dawley rats after 28 days of 30 mg kg-1 dose mixed with their diet was, was observed and demonstrated in an oral toxicity study. No genetic toxicity in the bone marrow of rat was observed [42]. This is summarized in Table 1. To remove the toxic effect of AgNPs, a modified Tollens process involving reduction of the cation [Ag(NH3)2]+ can be used for synthesis of AgNPs to reduce the toxicity of AgNPs, this is traditionally done by reducing silver ions (Ag+) to metallic silver (Ag) using reducing agents like Glucose and Ammonia. However, this can only reduce the toxicity of AgNPs to a certain limit.[43]. The above explanation is summarized in Table 1. Table 1 Toxicity on mammals Organism Dose concentration Exposure method Effect Measured Ref SpragueDawley rats Low dose of 1.74 X 104 particles cm3 ; medium dose of1.27 X 105 particles cm-3 ; high dose of 1.32 X 106 particles cm-3 of AgNPs size 1315 nm Inhalation exposure for 6hrs a day, 5 times a week for 4 weeks Size and number of Goblet cells containing neutral mucin increased. However, no remarkable changes in nasal and lungs canal. [39] SpragueDawley rats Low dose of 0.7 X 106 particles cm-3; medium-dose of 1.4 X 106 particles cm-3; high dose of 2.9 X 106 particles cm-3 of AgNPs size 18 nm Inhalation exposure for 6 hrs a day, 5 times a week for 13 weeks Lung inflammation and decrease in tidal volume and minute volume. [40] World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 480 SpragueDawley rats Low dose of 1.74 X 106 particles cm3 ; medium dose of 1.27 X 106 particles cm-3 ; high dose of 1.32 X 106 particles cm-3 of AgNPs size 1216 nm Inhalation exposure for 6 hrs per day,5 times a week for 4 weeks Both male and female rats show no significant changes in the body weight, hematology and blood biochemical values. [41] SpragueDawley rats Low dose of 30 mg kg-1; medium dose of 300 mg kg-1; high dose of 1000 mg kg -1 of AgNps size 60 nm Ingestion exposure in which the AgNPs are mixed with diet for 28 weeks Gender related difference in accumulation of AgNPs in kidneys; significant dose dependent changes in alkaline phosphate, cholesterol values. [42] 3.3. Toxicity in non-mammals Numerous non-mammals are been considered and used to test the adverse effects of AgNPs. It is not a surprise that majority of these tested and adversely affected non-mammals are aquatic organisms as a large quantity of AgNPs are released from fabrics and textile would flow into aquatic system. Few non-aquatic non-mammals such as Fruit Fly (Drosophila melanogaster) are studied. Zebrafish has been used as a correlative and predicted model in many studies to evaluate thre effect of AgNPs [44]. A study, in which embryos of Zebrafish were exposed to a dose concentration of 0.04-0.71 nM for 120 hours. It was noted that single AgNPs of size 11.6±3.5 nm could transport into the Zebrafish embryos through Chorion pore canal, AgNPs were detected in each development stage. At a concentration of 0.19 nM development abnormality could be triggered [45]. Another study consisted of synthesizing four different size of nanoparticles of size 3 nm, 10 nm, 50 nm, and 100 nm respectively, which were then tested on Zebrafish embryos to test its toxicity, only a few differences were observed between them. It was reported that AgNPs induced 100% mortality when exposed for 120 hours at 250 µM. At a dose of 100µM, variety of embryonic morphological deformations were reported [46]. In another study the author reported that larger AgNPs of size 41.6±9.1 nm were more toxic and produced sever deformation of Zebrafish than smaller AgNPs of size 11.6±3.5 nm [47]. Drosophila melanogaster commonly known as Fruit Fly has been used as a model organism in a great number of toxicity test due to its ease of manipulating and cultivating it. One such study on the toxicity of AgNPs on Drosophila melanogaster reported acute and chronic toxicity effect. By reporting acute toxicity, half of the flies tested failed to finish their development cycle when exposed to a concentration of 20 mg L-1. The fertility of Drosophila was decreased significantly after long time exposure to 5 mg L-1 AgNPs. However, due to adaptation the fecundity of Drosophila was regenerated [48]. In other study of the Larvae of Drosophila were exposed to a concentration of silver nanoparticles at 50 and 100 µg mL-1, which resulted in DNA damage and apoptosis related toxicity [49]. This is summarized in Table 2. Table 2 Toxicity in non-mammals Organism Dose concentration Exposure time Effect Measured Ref Zebrafish embryos Concentration of 0.04-0.71 nM of AgNPs size 11.6±3.5 nm 120 hours Development abnormality is reported. [45] Zebrafish embryos Concentration of 0.25,2.5,25,100 & 250µM 120 hours 100% mortality is reported, malformation of embryonic morphology. [46] Zebrafish embryos Dose concentration of 0.02 nM to 0.7 nM of AgNPs size of 41.6±9.1 nm 120 hours Development of abnormality and mortality dependent on dose. [47] Drosophila melanogaster In this the concentration for Acute toxicity is 10-100 mgL-1 Ag and Chronic toxicity at concentration of 5mgL-1 of AgNPs size 3µm in solid dispersion Ingestion exposure time of 10 days of AgNPs prepared in solid dispersion which are then added to culture medium Acute toxicity resulted in 50% of flies did not finish their development cycle. Chronic toxicity influences the fertility by adhering it [48] Drosophila melanogaster Exposed to the concentration of 50, 100 µmL of AgNPs size 10 nm. Ingestion exposure of 24 and 48 hours Introduction of Oxidative stress as a result of generation of ROS [49] World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 481 3.4. Toxicity in Plants Once the plants were exposed to AgNPs, remarkable changes were noted in the morphology of plants, commonly used parameters for assessing the phytotoxicity of AgNPs in plants are growth potential, seed germination, root growth and reduced biomass leaf area. Many plant species were been tested to study to Phytochemical nature of AgNPs. One of which is Arabidopsis thaliana also known as Mouse Ear Cress. In a literature Arabidopsis thaliana was exposed to AgNPs of size 41 nm at a concentration of 100-500 mg/L, this resulted in reduced root length, leaf expansion and photosynthesis efficiency and disruption of plasma membrane’s K+ efflux and Ca2+ influx, it also resulted in induced ROS accumulation [50]. In another experiment conducted Arabidopsis thaliana was exposed to 0.2 µgL concentration of AgNPs of size 10,20,40 and 80 nm which caused inhibition of development of root hair and repressed the transcriptional responses to microbial pathogen which results in increased bacterial colonization [51]. Arabidopsis thalian when exposed to concentration of 75-300 µgL-1 showed prolonged vegetative and shortened reproducible growth. It also decreased germination rate of offspring [52]. In a study of Lolium multiflorum plant, the plant was exposed to the concentration of 1-40 mgL-1 of AgNPs of size 6nm, root biomass decreased from 18.6±1.3 mg to 4.7±0.7 mg also the root length decreased from 7±0.6 cm to 0.7±0.08 cm [53]. When Arabidopsis thalian was exposed to a concentration of 67-535 µgL-1 this resulted in inhibition of seedling root elongation [54]. Inhibition of root growth, disruption of Thylakoid membrane structure and decrease in chlorophyll content was observed when Arabidopsis was exposed to s series of concentrations of 0.2, 0.5 and 3 mgL-1 [55]. This data is been summarized in Table 3. Table 3 Toxicity in Plants Organism Dose concentration Exposure time Effect Measured Ref Arabidopsis thaliana It is exposed to concentration of 100-5000 mgL-1 of AgNPs size 41 nm 3-7 days Induce ROS accumulation, Root length, leaf expansion and photosynthetic efficiency is reduced. Ca2+ is induced in cytoplasm. Inhibits K+ efflux and Ca2+ influx currents in plasma membrane. [50] Arabidopsis thaliana Is exposed to concentration of 0.2 µgL-1 of AgNPs size 10,20,40&80 7-20 days Root hair development is induced and transcriptional responses to microbial pathogens is repressed. [51] Arabidopsis thaliana Concentration of 75-300 µgL-1of AgNPs size 20 nm 21-45 days Decreases germination rate of offspring and reproductive growth. [52] Lolium multiflorum Exposed to the concentration of 1-40 mgL-1 of AgNPs size 6nm 7-21 days Root and shoot length is decreased. [53] Arabidopsis thaliana Exposed to concentration of 67-535 µgL-1 of AgNPs size 20,40 and 80 nm. 24-96 hours Inhibit seedling root elongation and AgNPs were aggregated at plasmodesmata. [54] Arabidopsis thaliana Exposed to concentration of 0.2,0.5 and 3 mgL-1 of AgNPs size 10 nm. 7-21 days Disruption if the Thylakoid membrane structure is disrupted and chlorophyll content is decreased. Inhibition of root growth. [55] 4. Synthesis of Silver nanoparticles 4.1. Chemical Synthesis 4.1.1. Chemical reduction The Chemical reduction method, also known as conventional chemical synthesis is the most common approach of synthesizing AgNPs [56]. This is generally carried out in the presence of precursor such as AgNO3. Different reducing agents such as sodium citrate, sodium borohydride, hydrogen, ethylene glycol or dimethylformamide (DMF) are used for the reduction of silver ions (Ag+). These reducing agents reduces silver ion (Ag+) to metallic silver (Ag) in aqueous or non-aqueous solution. This can cause agglomeration forming oligomeric clusters. Stabilizer such as World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 482 polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA) [57]. It is important to use stabilizer as it stabilizes dispersive AgNPs during preparation, avoiding agglomeration and oligomeric clusters [58]. Recently, recovery and synthesis of AgNPs from electronic waste have become a vital issue among the scholars, as silver is used to coat medical appliances. For this, initially 10 g of electronic waste is crushed to form a homogeneous powder which then was placed in an over for 10 minutes at 500°C, by this any possible contaminations would be removed. After which Nitric acid (HNO3) solution is added to dissolve the silver content from the homogeneous powder. Thereafter, liquid containing silver salt was centrifuged at 6000rpm. AgNO3 is collected and dried for 24 hours at 60°C under a vacuum of 10 millibars. From the obtained dried AgNO3, 5g was added to 100 ml of ethanol (has reductive role) which is then stirred for 30 minutes. 5% PVP is added dropwise as a stabilizer to avoid agglomeration. Finally, the system was mixed at a specific temperature and time. Usually, to investigate the effects the system is timed as 30,60,90,120 minutes and the samples were synthesized at temperatures 20,30,40 and 60 °C. The AgNPs obtained at 60°C for 60 minutes were of size 400 to 450 nm which were more significant as compared to those obtained at 30 minutes and 90 minutes [59]. This method is simple and cost-effective and produces uniformly sized nanoparticles under controlled condition. However, it does require careful control of reaction parameter to prevent agglomeration [57]. 4.1.2. Sol-Gel Method One of the methods that has gained prominence in the synthesis of silver nanoparticles is the sol-gel process, due to its versatility in producing nanoparticles in various forms such as complex, metal oxides, inorganic nanocomponents and chalcogenides [61]. This process involves preparation of gel-like solution by mixing the silver precursor (such as silver nitrate) with a metal complex (containing elements like calcium, titanium or strontium), this mixture is added to solvents such as alcohol or water [60,61]. The solution obtained as a result of mixing, undergoes a chemical reaction that often involves controlled heating which promotes nucleation and growth of AgNPs. Reaction conditions such as temperature and solvent type often plays a crucial role in determining the size and shape of AgNPs [60,63]. The AgNPs synthesized by depositing them within the thin films of metal oxides, such as TiO2, SiO2, ZrO2. These films are often heated at high temperature (e.g., The heating temperature for SiO2 is 600°C and for TiO2 the heating temperature is 500°C). The average nanoparticle size obtained is 10 nm [63]. AgNPs can be synthesized using hydrolytic sol-gel process at 400°C,600°C and 800°C, where the average particle size is 20nm and the silver nanoparticles are crystalline in shape [62]. The sol-gel technique is also performed at low temperatures (100°C) to produce silver-doped hydroxyapatite nanorods with an average diameter of 25 nm hexagonal cross sectional [60]. High temperature (400°C to 800°C) are typically used to achieve crystalline nanoparticles, lower temperatures can also be used with specific modifications. Besides temperature and gel composition, solvent plays an important role in determining the shape and size of the AgNPs [64]. Generally, organic solvents are preferred, due to their oxygen supplying characteristic for metal, which helps to control particle uniformity and size distribution [64]. The process enables customization of nanoparticles as it allows for a wide range of precursors and additives [67]. Additionally, the sol-gel process can synthesize AgNPs in hot aqueous environment under high pressure and also at low temperatures [61]. However, producing thick nanoparticledoped films without defects like cracks is difficult [65]. Often the sol-gel process is associated with costly precursors and reproducibility issues, particularly in large scale production [66]. The film quality is highly dependent on environmental conditions such as humidity and temperature [65]. 4.1.3. Chemical Vapor Deposition Technique The Chemical Vapor Deposition is one of the techniques to synthesize nanoparticles. It allows the synthesis of nanoparticles on the surface of 3D substrate [68]. The deposition process takes place in three steps, initially volatile precursor is introduced to the reactor chamber by a carrier gas (like H2, Ar or N2). This process requires volatile silver containing precursors that decomposes thermally to produce silver. Commonly, silver nitrate, silver acetate, or silver organometallic compounds like silver (I) penta-fluoro-propionate is used as a precursor in CVD methods. After this step, the precursor vapors are adsorbed on the substrate surface and intermediate products are formed, followed by formation of layers. Lastly, decomposition of products occurs on the heated substrate, which is followed by nucleation and growth of layer [68]. The factors that affect the quality of the nanoparticle produced are the methods used for precursor delivery, pressure in reactor chamber, chemical properties of carrier gas, rate of deposition, substrate surface temperature and duration of deposition [68,69]. The type of precursor used seems to be the most significant factor in this method. The CVD precursor should have the following characteristics: it should be appropriately volatile to achieve highest concentration of the precursor in vapor form, the precursor should be thermally stable to avoid premature degradation during transportation of vapors by carrier gas (like H2, Ar or N2), it should be able to thermally decompose on the surface of the substrate leading to the deposition of desired materials, it should be inexpensive and simple to synthesize and have very low toxicity [70]. World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 483 Usually, two types of compounds are used as precursors for CVD, namely silver nitrate (AgNO3) and silver (1) complex such as perfluorinated carboxylates. AgNO3 is widely used as precursor in techniques such as Flame Assisted CVD and Atmospheric Pressure CVD [70-72]. The Flame Assisted CVD (FACVD) enables the deposition of metallic silver layer of thickness 60-90 nm [70], when the substrate surface is heated this technique facilitates the deposition of silver metallic layer having thickness of 60-250 nm [71]. The FACVD method allows the formation of nanocomposite coating of Ag metal oxides (e.g., TiO2 and SiO2) in deposition process on large substrate area [70,73]. Atmospheric Pressure CVD is used to produce nanocomposite coating on textile surface which is composed of silicon with incorporated AgNPs [72]. Silver(I)acetate and silver (I) trifluoroacetate cannot be used as a precursor in conventional CVD methods such as Metal Organic CVD (MOCVD) and Plasma-Enhanced CVD (PECVD) due to their weak volatility, however continuous films of pure silver were deposited by these compounds with the help of Laser-Inducted CVD (LICVD) [68,74]. Silver(I)pentafluoro-propionate is considered as a good organic Ag CVD precursor since layers of AgNPs of diameter 20-60 nm were obtained on the surface of Si (111) substrate after 5 minutes of CVD process at 563K [75]. The CVD method enables scalability, purity, uniformity and control over the size and shape of nanoparticles. However, the process is costly [76]. 4.1.4. Reverse Micelle Process Reverse micelle process is a specific type of microemulsion technique, which is prominently used for the synthesis of silver nanoparticles. In this method surfactants such as sucrose fatty acid in organic solvent such as hexane or toluene produces reverse micelles [79]. Surfactants, reducing agents and organic solvents are used to enhance the stability, size and overall morphology of AgNPs [77]. There is a water pool inside the microemulsion which is a water phase that consist of reactants. The water phase serves as nanoreactors where silver ions (Ag+) are reduced to silver atoms (Ag) which then forms AgNPs. Hydrazine [83], ascorbic acid [77], sodium borohydride (NaBH4) [80] and glucose [81] are some of the regularly used reducing agents in this method. It was observed that hydrazine hydrate (N2H4.H2O) can yield much smaller AgNPs with higher dispersion as compared to sodium borohydride (NaBH4) which is a strong reducing agent [82]. So, the size distribution of AgNPs in controlled by the strength of reducing agent [77]. The size and distribution of AgNPs obtained also depends on the type of solvent and reducing agents used in the synthesis process [77]. Silver nanoparticles were synthesized in sodium dioctyl sulfosuccinate (AOT) reverse micelle in this ascorbic acid was used as a reducing agent. AgNPs were obtained with an average size of 6nm [77]. AOT microemulsion is generally used for for the synthesis of AgNPs [77]. AgNPs were prepared by using octadecyl amine (ODA) as solvent and sodium borohydride (strong reducing agent) as a reductant, this resulted in the AgNPs of average size 3.38 nm [78]. This method enables precise control over nanoparticle size and distribution as it provides many choices on the type of surfactants and solvent used [77]. It does not need any specialized equipment and extreme temperature or pressure conditions [79]. Due to the surfactant stabilization agglomeration tendency is low, it is scalable and could be used in large scale synthesis [79]. The AgNPs produced with AOT microemulsion may have poor surface plasmon characteristic [77]. 4.1.5. Wet Chemical Synthesis Wet chemical synthesis is one of the most commonly used methods for synthesizing silver nanoparticles; most for synthesizing AgNPs still rely on wet chemical reduction using a chemical reducing agent. In the conventional wet chemical synthesis of AgNPs strong reducing agents such as glucose, sodium borohydride, hydrazine and dimethyl formamide (DMF) is used [85]. PVP coated silver nanoparticles were synthesized by reduction with glucose in the presence of PVP at 90°C for up to 7000 minutes under ambient light this resulted in AgNPs of size 200 nm [84]. The wet chemical method can successfully offer narrow size distribution of AgNPs. Besides all these advantages reductants used in this method have reported to posses’ toxicity which might have adverse effect on human body. Hydrazine derivative compounds such as hydrazine hydrate is known to be carcinogenic and can cause irreparable damage to the vital organs such as lungs [86,87]. It has been ranked as a potential carcinogen that has threshold limit as low as 10 ppb by Environmental Protection Agency [86,88]. The nanoparticles obtained from hydrazine may contain remanent of hydrazine, making it unsuitable for biomedical uses. DMF has also reported to cause damage to liver [84]. NaBH4 which is also a strong reducing agent have adverse effect on lungs and may cause serious lung related problems [90]. Another wet chemical method used for the preparation of AgNPs is polyol method. In this method ethylene glycol is used as the solvent and reducing agent and PVP as surface stabilizer, this method is performed at 120°C-160°Cin the presence of salt mediator [91-93]. The polyol process is widely accepted method for the synthesis of AgNPs as it is non-hazardous and utilizes natural compounds to synthesize AgNPs at room temperature, in this method only one reagent is used as both reducing and capping agent [92]. However, there are many conditions such as the temperature (above 120°C) and concentration of precursor (0.1M or less), PVP to AgNO3 ratio plays an important role in size, morphology and yield of AgNPs, which limits their scalability [94]. World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 484 4.2. Green synthesis of silver nanoparticles The concept of green synthesis of silver nanoparticles is a ecofriendly approach to AgNPs production. The method utilized in the green synthesis of AgNPs are non-toxic, biological and non-hazardous which ensures minimum environmental toxicity and hazards related to human health [57,85,97,99]. The green synthesis aligns closely with chemical synthesis in terms of its principle, but avoids the use of hazardous toxic chemicals making it safer option [57]. The primary motivation behind green synthesis is to minimize the adverse effects of traditional chemical synthesis that often involves use of harmful chemical reducing agents such as NaBH4, N,N-DMF and hydrazine derivatives . The green synthesis synthesizes AgNPs by reducing silver ions (Ag+) to metallic silver (Ag) by using biological species or bio-based compounds [98]. This process is also known as biological synthesis as the bio-based compounds are often derived from microorganisms or plant extracts, which acts as reducing agent, replacing conventionally used toxic reducing agents [57]. While the biological synthesis plays a main role in green synthesis, it is not completely restricted to biological methods, there are several physical methods such as laser irradiation [98], microwave irradiation [100,101], ionizing radiation [98,103] and pulse radiolysis [98] have also been employed to synthesize AgNPs without the use of chemical reducing agents like hydrazine and NaBH4 [98]. However, these methods consume a huge amount of energy, which pose a challenge in terms of their cost effectivity and sustainability. Green synthesis presents itself as an alternative to conventional chemical and physical methods [96]. This is because while chemical synthesis often involves the use of toxic solvent and reducing agents and physical methods require sustainable energy input, the green synthesis strikes a balance by synthesizing AgNPs using natural reducing agents [57,102] and energy efficient techniques [57,85], thus making it ideal for mass production [95] and more economically feasible [57,95]. 4.2.1. Synthesis of silver nanoparticles using Plant extracts. Synthesis of silver nanoparticles using plant extract is an extremely cost-effective method of synthesis and hence can be a valuable alternative for large scale production of AgNPs [122]. In this, the plant extract is used as reducing agent and stabilizing agent for the synthesis of AgNPs which rules out toxicity caused by conventional chemicals used to synthesis AgNPs [123]. Due to their non-pathogenic characteristics and biocompatibility, AgNPs synthesized by plant extract are ideal for biomedical applications [104]. The plant extract consists of phenolic compounds such as alkaloids and flavonoids which provide the reagent with unique reducing and capping properties, these compounds are also soluble in water [105,106]. Plants naturally detoxify the ground water by removing impurities such as heavy metals [107]. Redox potential is one of the most significant factors in the detoxifying process [108], this can be used to utilize plants for reduction of metal cations (Ag+) and synthesize AgNPs. This process may be considered as in vivo and in vitro synthesis process [119]. The in vivo synthesis can be defined as the synthesis of AgNPs inside the plant on the other hand in vitro synthesis can be defined as the synthesis of AgNPs by the plant extract Torresday et al. [109] synthesized AgNPs by using in vivo synthesis process by using Alfalfa Sprouts. The obtained nanoparticles were of diameter 2-20 nm and were spherical in shape. This study reported that Ag was absorbed from the agar medium by the root hair of the plant and was transferred to the shoot. This study also reported the synthesis and nucleation of AgNPs within the plant tissue. In several studies it was reported that AgNPs could also be synthesized by using Brassica Juncea, in which AgNPs were reported to be in the plant biomass [111,112]. Flavones, terpenoids, polyphenols and catechins are phytochemical in plants that facilitates AgNPs synthesis [110,113]. Synthesizing AgNPs in plant phytochemicals can be advantageous as the water solubility of the phytochemicals simplify the process [114]. Plant parts such as roots, fruits, seeds and other aerial parts can be used for extraction of phytochemicals, which contain polyphenols that are strong antioxidants and have redox potential [114,119,121]. Makarov et al. [115], proposed a hypothesis which stated that when flavonoids are used as reducing agents it undergoes tautomerization that releases hydrogen, transforming flavonoids into keto-form. This leads to the reduction of silver ion (Ag+) to metallic silver (Ag). Functional groups such as hydroxy (-OH) groups are known to reduce Ag+ [114]. The size and morphology of AgNPs can be altered by selecting the plant source [120,116]. In recent times, using plant extract as reducing, stabilizing and capping agent for the synthesis of AgNPs has grown torrentially. AgNPs was synthesized by Johnson et al. [117] by using Odontosoria Chinensis extract, which resulted in the formation of spherical AgNPs of diameter 22.3-48.2 nm. Sivakumar et al. [118] used Parthenium hysterophorus extract to to synthesize spherical AgNPs having average size of 10.3±1.7 nm. In this the hydroxy group was responsible for the reduction of Ag+ and formation of AgNPs. The obtained AgNPs portrayed antibacterial activity and anti-cancer activity. This process is highly dependent on the plant extract composition and parameters such as pH, temperature and concentration ratio. The process is simple, cost-effective, environmentally friendly and had low reaction time. However, the mechanism for affecting the synthesis of process is unknown [57,119]. The examples of different plant extracts to synthesize AgNPs is given in Table 4. World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 491 [73] Varghese S, Elfakhri S, Sheel DW, Sheel P, Bolton FJ, Foster HA. Novel antibacterial silver-silica surface coatings prepared by chemical vapour deposition for infection control. Journal of Applied Microbiology. 2015, 115:11071116 [74] Lu YF, Takai M, Shiokawa T, Aoyagi Y. Growth of ultra-thin silver films by Excimer-laser-induced decomposition of silver acetate in air. Japanese Journal of Applied Physics, Part 2. 1994, 33:L1313-L1315 [75] Szłyk E, Piszczek P, Grodzicki A, Chaberski M, Goliński A, Szatkowski J, Błaszczyk T.CVD of Ag(I) complexes with tertiary phosphines and perfluorinated carboxylanes – A new class of silver precursors. Chemical Vapor Deposition. 2001, 7:1-6 [76] Zhang, K.-X., Wen, X., Yao, C.-B., Li, J., Zhang, M., Li, Q.-H., Sun, W.-J., Wu, J.-D. Chem. Phys.Lett.2018,698,147– 151. doi:10.1016/j.cplett.2018.03.018 [77] Singha, D., Barman, N., Sahu, K. J. Colloid Interface Sci. 2014, 413, 37–42. doi:10.1016/j.jcis.2013.09.009 [78] Yang, J., Li, Y., Jiang, B., Fu, Y. J. Nanophotonics 2018, 12, 036008. doi:10.1117/1.jnp.12.036008 [79] Noritomi, H., Umezawa, Y., Miyagawa, S., Kato, S. Adv. Chem. Eng. Sci. 2011, 1, 299– 304.doi:10.4236/aces.2011.14041 [80] Setua, P., Ghatak, C., Rao, V. G., Das, S. K., Sarkar, N.J. Phys. Chem. B 2012, 116, 3704–3712. doi:10.1021/jp203043k [81] Setua, P., Pramanik, R., Sarkar, S., Seth, D., Sarkar, N.J. Phys. Chem. B 2009, 113, 5677–5680. doi:10.1021/jp810229m [82] Solanki, J. N., Murthy, Z. V. P. Ind. Eng. Chem. Res. 2011, 50,7338–7344. doi:10.1021/ie200536q [83] Zhang, W., Qiao, X., Chen, J. Colloids Surf., A2007,299,22–28. doi:10.1016/j.colsurfa.2006.11.012 [84] Wang, H., Qiao, X., Chen, J., Ding, S. Coll. Surf. A: Physicochem. Eng. Aspects 2005, 256, 111−115. [85] Iravani, S., Korbekandi, H., Mirmohammadi, S. V., Zolfaghari, B. Res. Pharm. Sci. 2014, 9, 385–406 [86] Goswami, S., Aich, K., Das, S., Basu Roy, S., Pakhira, B., Sarkar, S. RSC Adv. 2014, 4, 14210–14214. doi:10.1039/c3ra46663a [87] Mahapatra, A. K., Karmakar, P., Manna, S., Maiti, K., Mandal, DJ. Photochem. Photobiol., A 2017,334,1–12. doi:10.1016/j.jphotochem.2016.10.032 [88] EPA, Risk Information System Division. Chemical AssessmentSummary of Hydrazine/Hydrazine sulfate.https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance_nmbr=352. [89] EPA, Risk Information System Division. Chemical Assessment Summary of N,NDimethylformamide.https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance_nmbr=511. [90] New Jersey Department of Health and Senior Services. Hazardous substance fact sheet on sodium borohydride. 1999. [91] Titkov, A. I., Gerasimov, E. Y., Shashkov, M. V., Logutenko, O. A., Bulina, N. V., Yukhin, Y. M., Lyakhov, N. Z. Colloid J. 2016, 78, 515–524. doi:10.1134/s1061933x16040189 [92] Kim, D., Jeong, S., Moon, J. Nanotechnology 2006, 17, 4019–4024. doi:10.1088/0957-4484/17/16/004 [93] Zhao, T., Sun, R., Yu, S., Zhang, Z., Zhou, L., Huang, H., Du, R.Colloids Surf., A 2010, 366, 197–202. doi:10.1016/j.colsurfa.2010.06.005 [94] Chen, C., Wang, L., Yu, H., Jiang, G., Yang, Q., Zhou, J., Xiang, W., Zhang, J. Mater. Chem. Phys.2008,107,13–17. doi:10.1016/j.matchemphys.2007.06.048 [95] Iravani, S. Green Chem. 2011, 13, 2638–2650. doi:10.1039/c1gc15386b [96] Kumar, P., Singh, P. K., Hussain, M., Kumar Das, A.Adv. Sci. Lett. 2016, 22, 3–7. doi:10.1166/asl.2016.6772 [97] Parveen, K., Banse, V., Ledwani, L. AIP Conf. Proc. 2016, 1724,020048. doi:10.1063/1.4945168 [98] Sharma, V. K., Yngard, R. A., Lin, Y. Adv. Colloid Interface Sci. 2009,145, 83–96. doi:10.1016/j.cis.2008.09.002 [99] Hussain, I., Singh, N. B., Singh, A., Singh, H., Singh, S. C.Biotechnol. Lett. 2016, 38, 545–560. doi:10.1007/s10529015-2026-7 World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 492 [100] Chen, J., Wang, J., Zhang, X., Jin, Y. Mater. Chem. Phys. 2008, 108,421–424. doi:10.1016/j.matchemphys.2007.10.019 [101] Francis, S., Joseph, S., Koshy, E. P., Mathew, B.Artif. Cells, Nanomed., Biotechnol. 2018, 46, 795– 804.doi:10.1080/21691401.2017.1345921 [102] Srikar, S. K., Giri, D. D., Pal, D. B., Mishra, P. K., Upadhyay, S. N. Green Sustainable Chem.2016,6,34–56. doi:10.4236/gsc.2016.61004 [103] Long, D., Wu, G., Chen, S. Radiat. Phys. Chem.2007,76,1126–1131. doi:10.1016/j.radphyschem.2006.11.001 [104] Amooaghaie, R., Saeri, M. R., Azizi, M. Ecotoxicol. Environ. Saf. 2015, 120, 400–408. doi:10.1016/j.ecoenv.2015.06.025 [105] Komes, D., Belščak-Cvitanović, A., Horžić, D., Rusak, G., Likić, S., Berendika, M. Phytochem. Anal. 2011, 22, 172– 180. doi:10.1002/pca.1264 [106] Rice-evans, C. A., Miller, N. J., Bolwell, P. G., Bramley, P. M., Pridham, J. B. Free Radical Res.1995,22,375–383. doi:10.3109/10715769509145649 [107] Tangahu, B. V., Sheikh Abdullah, S. R., Basri, H., Idris, M., Anuar, N., Mukhlisin, M. Int. J. Chem. Eng. 2011, 2011, 939161. doi:10.1155/2011/939161 [108] Antoniadis, V., Levizou, E., Shaheen, S. M., Ok, Y. S., Sebastian, A., Baum, C., Prasad, M. N. V., Wenzel, W. W., Rinklebe, J. Earth-Sci. Rev.2017,171,621–645. doi:10.1016/j.earscirev.2017.06.005 [109] Gardea-Torresdey, J. L., Gomez, E., Peralta-Videa, J. R., Parsons, J. G., Troiani, H., Jose-Yacaman, M. Langmuir 2003, 19, 1357–1361. doi:10.1021/la020835i [110] Marchiol, L. Ital. J. Agron. 2012, 7, e37. doi:10.4081/ija.2012.e37 [111] Haverkamp, R. G., Marshall, A. T., Van Agterveld, D. J. Nanopart. Res. 2007, 9, 697–700. doi:10.1007/s11051006-9198-y [112] Beattie, I. R., Haverkamp, R. G. Metallomics2011,3,628–632. doi:10.1039/c1mt00044f [113] Park, Y., Hong, Y. N., Weyers, A., Kim, Y. S., Linhardt, R. J. IET Nanobiotechnol. 2011, 5, 69–78. doi:10.1049/ietnbt.2010.0033 [114] Ratan, Z. A., Haidere, M. F., Nurunnabi, M., Shahriar, S. M., Ahammad, A. J. S., Shim, Y. Y., Reaney, M. J. T., Cho, J. Y. Cancers 2020, 12, 855. doi:10.3390/cancers12040855 [115] Makarov, V. V., Love, A. J., Sinitsyna, O. V., Makarova, S. S., Yaminsky, I. V., Taliansky, M. E., Kalinina, N. O. ActaNaturae 2014, 6, 35–44. doi:10.32607/20758251-2014-6-1-35-44 [116] Mukunthan, K. S., Balaji, S. Int. J. Green Nanotechnol.2012,4,71–79. doi:10.1080/19430892.2012.676900 [117] Antonysamy Johnson, M., Shibila, T., Amutha, S., Menezes, I. R. A., da Costa, J. G. M., Sampaio, N. F. L., Coutinho, H. D. M. Pharmaceuticals 2020, 13, 66. doi:10.3390/ph13040066 [118] Sivakumar, M., Surendar, S., Jayakumar, M., Seedevi, P., Sivasankar, P., Ravikumar, M., Anbazhagan, M., Murugan, T., Siddiqui, S. S., Loganathan, S. J. Cluster Sci. 2020, 1–11.doi:10.1007/s10876-020-01775-x [119] Khan, M., Shaik, M. R., Adil, S. F., Khan, S. T., Al-Warthan, A., Siddiqui, M. R. H., Tahir, M. N., Tremel, W. Dalton Trans. 2018, 47,11988–12010. doi:10.1039/c8dt01152d [120] Kumar, V., Yadav, S. K. J. Chem. Technol. Biotechnol.2009,84,151–157. doi:10.1002/jctb.2023 [121] Shaik, M. R., Khan, M., Kuniyil, M., Al-Warthan, A., Alkhathlan, H. Z., Siddiqui, M. R. H., Shaik, J. P., Ahamed, A., Mahmood, A., Khan, M., Adil, S. F. Sustainability 2018, 10, 913. doi:10.3390/su10040913 [122] Iravani S. Green synthesis of metal nanoparticlesusing plants. Green Chem. 2011, 13:2638-2650. [123] Vilchis-Nestor AR, Sánchez-Mendieta V, Camacho-López MA, Gómez-Espinosa RM,Camacho-López MA, ArenasAlatorre J. Solventless synthesis and optical properties of Au and Ag nanoparticles using Camellia sinensis extract. Materials Letters. 2008, 62:3103–3105. [124] Rolim, W. R., Pelegrino, M. T., de Araújo Lima, B., Ferraz, L. S., Costa, F. N., Bernardes, J. S., Rodigues, T., Brocchi, M., Seabra, A. B. Appl. Surf.Sci.2019,463,66–74. doi:10.1016/j.apsusc.2018.08.203 [125] Kumar, B., Smita, K., Cumbal, L., Debut, A. Saudi J. Biol. Sci. 2017,24, 45-50.doi:10.1016/j.sjbs.2015.09.006 World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 493 [126] Dhand, V., Soumya, L., Bharadwaj, S., Chakra, S., Bhatt, D., Sreedhar, B. Mater. Sci. Eng., C 2016, 58, 36– 43.doi:10.1016/j.msec.2015.08.018 [127] Hu, S., Hsieh, Y.-L. Int. J. Biol. Macromol. 2016,82,856862.doi:10.1016/j.ijbiomac.2015.09.066 [128] Ibrahim, H. M. M. J. Radiat. Res. Appl. Sci. 2015, 8, 265–275.doi:10.1016/j.jrras.2015.01.007 [129] Alsammarraie, F. K., Wang, W., Zhou, P., Mustapha, A., Lin, M.Colloids Surf., B 2018, 171, 398– 405.doi:10.1016/j.colsurfb.2018.07.059 [130] El-Refai, A. A., Ghoniem, G. A., El-Khateeb, A. Y., Hassaan, M. M.J. Nanostruct. Chem. 2018, 8, 71–81. doi:10.1007/s40097-018-0255-8 [131] Kalishwaralal K, Deepak V, Ramkumarpandian S, Nellaiah H, Sangiliyandi G. Extracellularbiosynthesis of silver nanoparticles by the culturesupernatant of Bacillus licheniformis. Mater Lett.2008, 62:4411-4413 [132] Kalishwaralal K, Deepak V, Ramkumarpandian S, Bilal M, Gurunathan S. Biosynthesis of silvernanocrystals by Bacillus licheniformis. Colloids and Surfaces B: Biointerfaces. 2008, 65:150-153 [133] Saifuddin N, Wong CW, Nur Yasumira AA.Rapid biosynthesis of silver nanoparticles using culture supernatant of bacteria with microwave irradiation. E-Journal of Chemistry. 2009, 6:61-70. [134] Mokhtari N, Daneshpajouh S, Seyedbagheri S, Atashdehghan R, Abdi K, Sarkar S, et al. Biological synthesis of very small silver nanoparticles by culture supernatant of Klebsiella pneumonia: The effects of visible-light irradiation and the liquid mixing process. Mater Res Bull. 2009, 44:1415-1421 [135] Shivaji, S., Madhu, S., Singh, S. Process Biochem. (Oxford, U. K.) 2011, 46, 1800–1807. doi:10.1016/j.procbio.2011.06.008 [136] Kalimuthu, K., Suresh Babu, R., Venkataraman, D., Bilal, M., Gurunathan, S. Colloids Surf., B 2008, 65, 150–153. doi:10.1016/j.colsurfb.2008.02.018 [137] Shahverdi AR, Minaeian S, Shahverdi HR, Jamalifar H, Nohi A. Rapid synthesis of silver nanoparticles using culture supernatants of Enterobacteria: A novel biological approach Process Biochemistry. 2007, 42:919-923. [138] Lateef, A., Adelere, I. A., Gueguim-Kana, E. B., Asafa, T. B., Beukes, L. S. Int. Nano Lett. 2015, 5, 29– 35.doi:10.1007/s40089-014-0133-4 [139] Galvez, A. M., Ramos, K. M., Teja, A. J., Baculi, R.J. Microbiol., Biotechnol. Food Sci. 2019,2019,970978.doi:10.15414/jmbfs.2019.8.4.970-978 [140] Muthulakshmi, K., Uma, C., Sivagurunathan, P., Yoganathan, K., Satheeshkumar, S. J. Pharmacogn. Phytochem. 2018, 7, 741–747. [141] Nanda, A., Saravanan, M. Nanomedicine (N.Y.,NY,U.S.)2009,5,452–456. doi:10.1016/j.nano.2009.01.012 [142] Husain, S., Afreen, S., Hemlata, Yasin, D., Afzal, B., Fatma, T. J. Microbiol. Methods 2019, 162, 77– 82.doi:10.1016/j.mimet.2019.05.011 [143] Dahoumane, S. A., Mechouet, M., Alvarez, F. J., Agathos, S. N., Jeffryes, C. Bionatura 2016, 1, 196– 201.doi:10.21931/rb/2016.01.04.7 [144] Rahman, A., Kumar, S., Bafana, A., Dahoumane, S. A., Jeffryes, C. Molecules 2019, 24, 98. doi:10.3390/molecules24010098 [145] da Silva Ferreira, V., ConzFerreira, M. E., Lima, L. M. T. R., Frasés, S., de Souza, W., Sant’Anna, C. Enzyme Microb. Technol.2017, 97, 114–121. doi:10.1016/j.enzmictec.2016.10.01 [146] Monteiro, C. M., Castro, P. M. L., Malcata, F. X. Biotechnol. Prog.2012, 28, 299–311. doi:10.1002/btpr.1504 [147] Barwal, I., Ranjan, P., Kateriya, S., Yadav, S.C.J. Nanobiotechnol.2011,9,56. doi:10.1186/1477-3155-9-56 [148] Jena, J., Pradhan, N., Prasad Dash, B., Behari Sukla, L., Panda, P. Int. J. Nanomater. Biostructures 2013, 3, 1–8 [149] Muthusamy, G., Thangasamy, S., Raja, M., Chinnappan, S., Kandasamy, S. Environ. Sci. Pollut.Res.2017,24, 1945919464.doi:10.1007/s11356-017-9772-0 [150] Sathishkumar, R. S., Sundaramanickam, A., Srinath, R., Ramesh, T., Saranya, K., Meena, M., Surya, P. J. Saudi Chem. Soc. 2019, 23,1180–1191. doi:10.1016/j.jscs.2019.07.008 World Journal of Biology Pharmacy and Health Sciences, 2025, 21(02), 476-494 494 [151] Dahoumane, S. A., Wujcik, E. K., Jeffryes, C. Enzyme Microb. Technol. 2016, 95, 13–27. doi:1 0.1016/j.enzmictec.2016.06.008 [152] Dahoumane, S. A., Mechouet, M., Wijesekera, K., Filipe, C. D. M., Sicard, C., Bazylinski, D. A., Jeffryes, C. Green Chem. 2017, 19, 552–587. doi:10.1039/c6gc02346k [153] Ahmad A, Mukherjee P, Senapati S, Mandal D,Khan MI, Kumar R, et al. Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium oxysporum colloids and surfaces B: Biointerfaces2003, 28:313-318. [154] Macdonald IDG, Smith W. Orientation of Cytochrome c adsorbed on a citrate-reduced silver colloid surface. Langmuir. 1996, 12:706-713. [155] Fernández, J. G., Fernández-Baldo, M. A., Berni, E., Camí, G., Durán, N., Raba, J., Sanz, M. I. Process Biochem. (Oxford, U. K.)2016, 51, 1306–1313. doi: 10.1016/j.procbio.2016.05.021 [156] Korbekandi, H., Mohseni, S., Mardani Jouneghani, R., Pourhossein, M., Iravani, S. Artif. Cells, Nanomed., Biotechnol. 2016,44, 235–239. doi:10.3109/21691401.2014.937870 [157] Sastry, M., Ahmad, A., Islam Khan, M., Kumar, R. Curr. Sci. 2003, 85,162–170. [158] Naqvi, S. Z., Kiran, U., Ali, M. I., Jamal, A., Hameed, A., Ahmed, S., Ali, N. Int. J. Nanomed.2013,8,3187–3195. doi:10.2147/ijn.s49284 [159] Ma, L., Su, W., Liu, J.-X., Zeng, X.-X., Huang, Z., Li, W., Liu, Z.-C., Tang, J.-X. Mater. Sci.Eng.,C2017,77,963–971. doi:10.1016/j.msec.2017.03.294 [160] AbdelRahim, K., Mahmoud, S. Y., Ali, A. M., Almaary, K. S., Mustafa, A. E. Z. M. A., Husseiny, S. M. Saudi J. Biol. Sci. 2017, 24, 208–216. doi:10.1016/ j.sjbs.2016.02.025 [161] Yang, C., Jung, S., Yi, H. Biochem. Eng. J. 2014, 89, 10–20. doi: 10.1016/j.bej.2013.12.008 [162] Dujardin, E., Peet, C., Stubbs, G., Culver, J. N., Mann, S. Nano Lett. 2003, 3, 413–417. doi:10.1021/nl034004o [163] Lee, S.-Y., Royston, E., Culver, J. N., Harris, M. T. Nanotechnology 2005, 16, S435–S441. doi:10.1088/09574484/16/7/019 [164] Thangavelu, R. M., Ganapathy, R., Ramasamy, P., Krishnan, K. Arabian J. Chem. 2020, 13, 2750–2765. doi: 10.1016/j.arabjc.2018.07.006 [165] Young, M., Debbie, W., Uchida, M., Douglas, T.Annu. Rev. Phytopathol. 2008, 46, 361–384. doi: 10.1146/annurev.phyto.032508.131939 [166] Adigun, O. O., Retzlaff-Roberts, E. L., Novikova, G., Wang, L., Kim, B.-S., Ilavsky, J., Miller, J. T., Loesch-Fries, L. S., Harris, M. T.Langmuir2017,33,1716–1724. doi: 10.1021/acs.langmuir.6b03341 [167] Jeevika, A., Ravi Shankaran, D. J. Colloid InterfaceSci.2015,458,155–159. doi:10. 1016/j.jcis.2015.07.045 [168] Soleimani, F. F., Saleh, T., Shojaosadati, S. A., Poursalehi, R. Bionanosci. 2018, 8, 72–80. doi:10.1007/s12668017-0423-1