Bioengineered Silver Nanoparticles: Next-Generation Biogenic Synthesis Strategies for Precision Biomedical Applications

Silver nanoparticles (AgNPs) have attracted substantial scientific interest in biomedical research owing to their unique physicochemical characteristics, broad-spectrum antimicrobial activity, plasmonic properties, and therapeutic versatility. Although conventional physicochemical synthesis methods enable controlled NPs fabrication, their dependence on hazardous reagents, elevated energy input, and environmentally detrimental processing conditions has stimulated the development of sustainable biogenic alternatives. Biological synthesis utilizing plants, microorganisms, fungi, algae, and purified biomolecules has emerged as an eco-friendly and bio-compatible strategy for AgNP fabrication, enabling simultaneous reduction, stabilization, and intrinsic biofunctionalization of NPs. However, traditional biogenic synthesis remains constrained by limited mechanistic understanding, poor batch reproducibility, inadequate control over physicochemical properties, and challenges in large-scale manufacturing. Recent advances in bioengineering have transformed this field through the integration of metabolic engineering, synthetic biology, microfluidic-assisted synthesis, artificial intelligence-guided process optimization, and continuous-flow biomanufacturing, collectively enabling precision fabrication of biogenic AgNPs with enhanced uniformity, scalability, and functional tunability. Furthermore, strategic surface engineering and functionalization have expanded the applicability of biogenic AgNPs across targeted anticancer therapy, antimicrobial intervention, wound healing, regenerative medicine, drug delivery, and theranostic imaging. Despite these advancements, critical challenges remain regarding nano-bio interactions, toxicological safety, regulatory compliance, and translational scalability. Unlike conventional reviews focused primarily on green synthesis approaches, this review critically highlights emerging bioengineering paradigms that enable programmable, scalable, and precision-controlled biogenic AgNP fabrication. This review comprehensively examines next-generation paradigms and strategies for AgNPs biosynthesis, elucidates the molecular mechanisms governing their formation, highlights emerging functionalization and biomedical application paradigms, and discusses current translational barriers. Forming biogenic composites of AgNPs and heteroatom doped carbon nanodots needs intense research in near future.