Green biogenic silver nanoparticles, therapeutic uses, recent advances, risk assessment, challenges, and future perspectives

Green nanotechnology has gained much interest in the development of nanoparticles owing to its reliability, safety and eco-accommodating methods of synthesis, with exceptional properties (physical, chemical, and biological), and applications. Silver nanoparticles (Ag-NPs) are one of the most well established nanocarriers that have been explored for pharmaceutical purposes due to their obvious advantages over synthetic approaches. Synthetic methods are associated with hazardous byproducts, instability issues, and are generally time consuming expensive procedures having serious environmental concerns. The present review compiles various sources (fungi, plant, and bacteria), their advantages, therapeutic benefits, risk assessment, challenges, and future perspectives of Ag-NPs. We have emphasized comprehensive details of green Ag-NPs used for various pharmacological properties (antimicrobial, cytotoxicity, antifungal, anti-parasitic, and antioxidant) followed by certain limitations and risk assessments when tailored as drug delivery systems. The comparative assessment and major findings of various reports have been elaborately highlighted and are covered in the review. A summary of key findings deliberating the unique features of natural sources namely, ease of availability, safety concerns, stability, green techniques, various challenges in synthesis (negative consequences of nanomaterials), and technology transfer aspects from laboratory to bed, have been included in this review so that readers can be aware of basic information required for developing green-based nanocarriers as drug delivery platforms. Finally, various recent advances in metal nanoparticle preparations using sonochemical and microwave assisted methods have been covered with prime outcomes and related challenges. The present review also emphasizes on the benefits of various green sources for developing Ag-NPs, their advantages over conventional approaches, pharmaceutical applications, related challenges, future prospects, and recent advancements.