**1. Introduction**

The distinctive characteristics of size, shape, and morphology of nanoparticles facilitate their interaction with bacteria, plants, and animals [1–4]. Silver nanoparticles (Ag NPs) have demonstrated remarkable bactericidal efficacy against a diverse array of microorganisms [5–7]. These entities are formulated from diverse viewpoints, frequently for the purpose of examining their morphology or physical attributes. Certain authors have employed a chemical approach [8] and have erroneously conflated it with green synthesis, albeit unintentionally. The utilization of Ag NPs in various fields such as electronics, catalysis, pharmaceuticals, and biomedicine for regulating microorganism proliferation in biological systems has rendered them environmentally sustainable [6, 9]. The process of synthesizing Ag NPs through biogenic means entails the utilization of microorganisms such as bacteria, fungi, yeast, actinomycetes, as well as plant extracts [9, 10]. In contemporary times, various components of plants, including but not limited to flowers, leaves, and fruits, as well as enzymes, have been employed in the production of gold and silver nanoparticles. The physical characteristics of nanoparticles, including their dimensions, shape, and durability, are contingent upon various factors such as the preparation technique employed, the solvent utilized, the concentration of the solution, the potency of the reducing agent, and the temperature conditions [9, 10].

Among the various nanoparticles that have been developed and characterized, silver nanoparticles hold a prominent position due to their innate ability to function as an antimicrobial agent, even in their solid state. Despite being acknowledged for its importance at an earlier time, its potential was not fully utilized, with the exception of its application in traditional medicine and numismatics. Approximately 320 tons of silver nanoparticles (Ag NPs) are produced annually for utilization in various applications such as nanomedical imaging, biosensing, and food products [11, 12].

The prevalence of multidrug-resistant bacterial and viral strains is persistently rising, attributed to genetic mutations, environmental pollution, and alterations in ecological circumstances. In order to overcome this dilemma, researchers are endeavoring to create pharmaceuticals for the management of said microbial infections. Several metal salts and metal nanoparticles have demonstrated efficacy in impeding the proliferation of various pathogenic bacteria. Silver and silver nanoparticles (Ag NPs) hold a significant position in the category of metals utilized as antimicrobial agents since ancient times [13, 14]. Silver salts are employed as a means of impeding the proliferation of diverse bacterial strains within the human body. Antimicrobial agents are employed in medical applications such as catheterization, wound care, and burn treatment to safeguard against potential infection [15, 16]. According to Das et al. [17], the growth of certain bacteria can be effectively inhibited by smallsized silver nanoparticles (Ag NPs). Silver nanoparticles (Ag NPs) that are produced using silk sericin (SS), a protein that is soluble in water and extracted from silkworms at a pH of 11, are composed of hydrophilic proteins that possess polar groups such as hydroxyl, carboxyl, and amino functional groups. Functional groups present in the aforementioned molecules exhibit reducing properties towards AgNO3, resulting in the formation of metallic silver [18]. It has been proposed that the hydroxyl groups present in SS are capable of forming a complex with silver ions, thereby impeding their aggregation or precipitation [19, 20]. The elemental state of Ag NPs may experience segregation as a result of the presence of large molecules within the solvent. However, it is unlikely that they will form complexes since both entities are neutral. The screening of the antibacterial efficacy of silver nanoparticles (Ag NPs) capped with SS has been conducted against both gram-positive and gram-negative bacterial strains. The study revealed that the minimum inhibitory concentration (MIC) ranges from 0.001 to 0.008 mM for various microorganisms, including *Bacillus subtilis*, *Staphylococcus aureus*, *Escherichia coli*, *Pseudomonas aeruginosa*, and *Acinetobacter baumannii*.

While there have been numerous publications on the biosynthesis and characterization of silver nanoparticles, there is a dearth of information regarding their green synthesis, biological properties, and mechanism of action [18]. This review aims to provide a comprehensive overview of the biosynthesis process of silver nanoparticles (Ag NPs) using various sources such as plant extracts, bacteria, fungi, viruses, and

actinomycetes. The potential of these agents as biological agents and their mechanisms of action have been the subject of discussion [21].
