Sustainable Fabrication of Onion-Peel Biogenic Silica Nanoparticles for Multimodal Characterization and In Vitro Bioactivity Profiling

Introduction: This study aims to develop a sustainable method for synthesizing Biogenic Silica Nanoparticles (bSNPs) from onion peel waste and evaluate their physicochemical properties and in vitro bioactivity. Methods: Biogenic Silica Nanoparticles (bSNPs) were prepared via an optimized acid–base sol–gel method and characterized by SEM, EDX, AFM, FTIR, and XRD. Antioxidant activity (DPPH assay), anti-inflammatory activity (protein denaturation), and DNA interaction (agarose gel) were assessed in vitro. Results: Biogenic Silica Nanoparticles (bSNPs) exhibited nanoscale dimensions (~120–125 nm) with spheroidal morphology and rough surface characteristics. FTIR and XRD confirmed amorphous silica. Dose-dependent antioxidant and anti-inflammatory activity, as well as DNA binding, were observed. discussion: The study demonstrates a sustainable and effective synthesis of biogenic silica nanoparticles (bSNPs) from onion peel agro-waste using an optimized acid–alkali sol–gel approach. The physicochemical characterization confirmed the successful formation of high-purity, amorphous silica nanoparticles with stable structural features, supporting the suitability of onion peel as a renewable silica source. Spectroscopic and microscopic analyses revealed predominantly spherical nanoparticles with nanoscale dimensions and surface characteristics favorable for biological interactions. The presence of characteristic Si–O–Si vibrations and a broad amorphous diffraction pattern further validated the formation of structurally stable silica. The observed particle size and surface roughness are consistent with previously reported biogenic silica systems and are advantageous for biomedical applications. The bSNPs exhibited significant dose-dependent antioxidant and anti-inflammatory activities, indicating their potential to mitigate oxidative stress and inflammatory responses. Additionally, the effective interaction with genomic DNA, evidenced by progressive retardation in agarose gel electrophoresis, suggests strong biomolecular affinity and highlights their promise for nucleic acid delivery and therapeutic applications. Overall, the findings emphasize the value of agro-waste-derived silica nanoparticles as environmentally friendly, biologically active nanomaterials, with promising potential for future oral and topical drug-delivery systems. Discussions: Biogenic Silica Nanoparticles (bSNPs) were synthesized from onion peel biomass via a two-acid sol–gel process. Spectroscopic and crystallographic analyses confirmed the successful synthesis of homogeneous amorphous silica. bSNPs exhibited effective biomolecular interactions. Conclusion: Onion peel-derived bSNPs are durable, environmentally friendly nanomaterials with promising antioxidant, anti-inflammatory, and DNA-binding potential for biomedical applications.