Advances in silver nanoparticles: unraveling biological activities, mechanisms of action, and toxicity

Silver nanoparticles (AgNPs) have demonstrated exceptional antimicrobial activity, effectively targeting bacterial, fungal, and viral pathogens. This broad-spectrum antimicrobial efficacy makes AgNPs a valuable co-treatment alongside antibiotics, potentially mitigating the growing issue of antimicrobial resistance. Beyond their antimicrobial properties, AgNPs exhibit significant anticancer activity, employing mechanisms such as apoptosis induction and the inhibition of tumor growth and metastasis to selectively target cancer cells. Furthermore, AgNPs exhibit antioxidant potential of scavenging free radicals and reducing oxidative stress within biological systems. While AgNPs are non-toxic to humans at low concentrations, their toxicity is influenced by many factors besides concentration such as size, shape and surface charge. These multifaceted properties of AgNPs underscore the their potential in medical and therapeutic applications, such as wound dressings, catheters, medical devices, health supplement drink as well as targeted drug delivery. This study provides an overview of the characteristics of AgNPs, their diverse bioactivities, and the evidence supporting their mechanisms for effectively inhibiting bacterial growth, viral replication, cancer proliferation, and metastasis. Additionally, updated information on the toxicity, biosafety, and recent medical applications of AgNPs is discussed.