Silver nanoparticles (AgNPs) are widely recognized for their unique optical, electronic, and antibacterial properties, enabling their use in biosensing, photonics, electronics, drug delivery, and antimicrobial treatments. Green chemistry-based biological synthesis methods offer an eco-friendly alternative to traditional chemical techniques. Among metallic nanoparticles (NPs) and metal oxides, those derived from plant extracts exhibit notable medicinal properties. Due to their exceptional stability and low chemical reactivity, AgNPs are particularly well-suited for various biological applications. AgNPs can be synthesized through chemical, physical, or biological methods, each with distinct benefits and challenges. Chemical and physical approaches often involve complex purification, reactive reagents, and high energy demands, while biological methods, though slower, provide sustainable solutions. The chosen synthesis method strongly influences the stability, size, and purity of the resulting NPs. This review emphasizes the importance of selecting appropriate synthesis methods to optimize the characteristics and functionality of silver NPs. It consolidates research spanning the past two decades, including the most recent findings from 2024. A comprehensive electronic search of databases such as PubMed, Scopus, ScienceDirect, Cochrane, and Google Scholar was conducted to provide an up-to-date overview of advances in the synthesis and applications of silver nanoparticles.

Gold nanoparticles (AuNPs) are renowned for their unique optical, electronic, and biocompatible properties, making them ideal for applications in drug delivery, diagnostics, imaging, and materials science. With green chemistry-based biological synthesis methods gaining popularity, eco-friendly alternatives to traditional chemical and physical methods techniques have emerged. Plant extract-derived AuNPs stand out for their remarkable medicinal properties, stability, and low reactivity, enhancing their biological applicability. This review explores the different synthesis methodschemical, physical, and biologicalhighlighting their advantages and challenges. We summarize the latest research (Updated until March, 2025), focusing on the most recent developments in the synthesis and multifield application of AuNPs, offering a comprehensive perspective on their potential.

AgNPs have gained significant attention due to their unique physicochemical properties, making them valuable across a range of fields including medicine, textiles, and household products. With their strong antimicrobial and antiviral properties, AgNPs have shown promise in treating infections, particularly in wound care management. This review explores the mechanisms underlying the antiviral activities of AgNPs, as well as the methods used for their synthesis, which include physical, chemical, and biological approaches. The review also addresses the potential limitations of AgNPs, including their cytotoxicity to humans and the environment. The interaction between AgNPs and microorganisms, particularly viruses, varies based on synthesis methods and particle morphology. As viral infections, including resistant strains, present major global health challenges, there is a growing need for alternative antiviral therapies. Metal nanoparticles like AgNPs offer potential advantages over conventional antiviral drugs due to their broad target range, which reduces the likelihood of resistance development. This review highlights AgNPs’ effectiveness against a variety of viruses, such as HIV, hepatitis B, and respiratory syncytial virus, and discusses their potential for use in novel antiviral treatments. The review also examines AgNPs’ toxicity, offering insights into their future therapeutic roles.

Background: One of the foremost causes of microbial infections and propagation is improper sanitation and hygiene maintained in public places. Accumulation of stains and microbes results in the spread of infections. Also, due to the extensive use of non-renewable materials like petrochemicals, etc., there is an increasing demand for sustainable growth in the coating industries. Currently, there is no such technology that tackles this problem. Methods: Our present work aims to find a prolonged solution for these problems for the first time by synthesizing and formulating bio-based coatings with inherent antimicrobial properties and durable surface properties with a fast air-curing system. A formulation of alkyd and polyesteramide resins from castor, neem, and karanja oils was crosslinked with isocyanates to form the surface coatings. An esterification reaction of castor oil monoglyceride and phthalic anhydride synthesized the castor oil alkyd resin. The corresponding neem and karanja oil polyesteramides were synthesized by amidation with diethanolamine, followed by an esterification reaction. Results: The coatings exhibit an antimicrobial efficacy of 74%–84% against both Gram-positive and Gram-negative bacteria and contain 76.5% bio-based content. Factors such as thermal stability, physicochemical properties, and chemical and solvent stability were studied. After 24 h of inoculation with 40% polyesteramide resin (AMRESN-4), E. coli and S. aureus CFU values decreased from 6 × 10⁵ to 0.28 × 10⁵ CFU/g and from 5.7 × 10⁵ to 0.26 × 10⁵ CFU/g, respectively. These bio-based coatings are particularly suited for environments requiring high durability and antimicrobial protection, such as food-processing facilities, healthcare settings, and public restrooms.

Zinc nanoparticles (Zn-NPs) are well-known versatile nanomaterials with a wide range of applications across diverse fields. Often, they range from ≈ 1 to 100 nm and have superior surface reactivity and excellent optical properties. Extensive research has demonstrated that these nanoparticles offer several advantages in fields such as medicinal applications, organic synthesis, agricultural applications, drug delivery, textile coatings, and food technology. Green synthesis of Zn-NPs offers several advantages, such as environmentally benign, cost-effective routes and improved bioactivity. This review summarizes recent papers (mostly from 2010 to 2025, extracted from Scopus/Web of Science/Google Scholar) on synthesis methodologies, characterization techniques, and emerging applications of various Zn-NPs, providing insights that support future innovations and the safe integration of Zn-NPs into varied systems.