Antibacterial Activity and Acute Cytocompatibility of Green-Synthesized Niobium-Based Nanomaterials Reduced by Ascorbic Acid, Tannic Acid, and Quercetin

Green synthesis represents an environmentally benign and sustainable strategy for producing nanomaterials with enhanced biological functionality and reduced toxicity. Niobium has shown great potential as a biomaterial under physiological conditions. This study aimed to investigate the use of natural antioxidants, ascorbic acid (AA), tannic acid (TA), and quercetin (QUE), as eco-friendly reducing and stabilizing agents in the green synthesis of niobium-based nanomaterials (Nbnano). The obtained nanomaterials were characterized by UV-Vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning-transmission electron microscopy (STEM), scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDX), and zeta potential analysis, indicating the formation of hydrated niobium pentoxide (Nb2O5·nH2O) nanomaterials with well-preserved structural organization and morphology. Acute cytotoxicity assays using VERO-CCL81 cells revealed that antioxidant-mediated synthesis significantly reduced the toxic effects of Nbnano, increasing their cytocompatibility. All nanomaterials exhibited antibiofilm activity against Escherichia coli, effectively reducing bacterial adhesion and biofilm formation. Except for AA-mediated Nbnano, the systems also demonstrated bactericidal activity, revealing their dual action against planktonic and sessile bacterial forms. Overall, the green synthesis of niobium nanomaterials using natural antioxidants represents a sustainable and effective strategy for developing multifunctional materials with promising antibacterial and antibiofilm performance, coupled with reduced cytotoxicity. These findings highlight the potential of niobium-based nanomaterials for biomedical and antifouling applications.