Sustainable bionanomaterials from agro-waste: bridging green chemistry and biomedical innovation

The growing demand for sustainable materials has accelerated interest in the valorization of agro-waste residues as renewable precursors for advanced bionanomaterials. This review systematically evaluates recent literature (2015–2026) on the conversion of agro-waste biomass into nanoparticles (NPs), including metallic, non-metallic, polymeric, and carbon-based nanostructures. Relevant studies were selected from major scientific databases based on predefined inclusion criteria, including (i) use of agro-waste-derived precursors, (ii) experimental validation of nanoparticle synthesis, and (iii) reported physicochemical or biological characterization. Studies lacking reproducible characterization or clear methodological details were excluded. Comparative analysis was performed using reported metrics such as particle size distribution, zeta potential, synthesis yield, cytotoxicity (cell viability assays), antimicrobial efficacy (MIC/zone of inhibition), and stability under varying environmental conditions. The review examines synthesis mechanisms and physicochemical characteristics of agro-waste-derived nanomaterials, highlighting trends observed across different biomass sources. While several studies report improved biocompatibility, colloidal stability, and multifunctional activity relative to conventionally synthesized counterparts, these outcomes are context-dependent and vary with precursor composition, synthesis conditions, and nanoparticle class. Quantitative comparisons across studies indicate that green-synthesized NPs often demonstrate reduced cytotoxicity and comparable or enhanced biological activity in vitro ; however, variability in experimental design and reporting standards limits direct benchmarking. Emerging biomedical applications including antimicrobial, antioxidant, anti-inflammatory, wound healing, tissue engineering, biosensing, and drug delivery are discussed with emphasis on experimentally validated findings. Green synthesis approaches are evaluated alongside traditional physicochemical methods, with reported advantages including lower energy requirements, reduced use of hazardous reagents, and integration with waste valorization strategies. However, inconsistencies in scalability, reproducibility, and long-term safety assessment remain significant challenges. In addition to biomedical relevance, the role of agro-waste valorization in supporting sustainable bioprocessing, waste reduction, and circular economy frameworks is considered. Overall, agro-waste-derived nanomaterials represent a promising yet evolving research area, where future progress will depend on standardized evaluation protocols, robust comparative studies, and improved translational validation.