Combination of Paraconiothyrium brasiliense fabricated titanium dioxide nanoparticle and antibiotics enhanced antibacterial and antibiofilm properties: A toxicity evaluation

Antimicrobial resistance (AMR) causes global consequences through increased mortality and economic loss. Antimicrobial drugs including nanomaterials are an emerging environmental impact. Hence, this work aimed to synthesize and characterize the titanium dioxide nanoparticles (TiO 2 NPs) using the aqueous extract of endophytic fungus Paraconiothyrium brasiliense (Pb) for enhancing the antibacterial efficiency of existing standard antibiotics at minimum concentration. The FTIR and XRD results confirmed the capping of functional molecules and the crystalline nature of Pb–TiO2 NPs. The spherical-shaped TiO2 NPs with the size of 57.39 ± 13.65 nm were found in TEM analysis. The average hydrodynamic size (68.43 ± 1.49 d. nm) and the zeta potential (−19.6 ± 1.49 mV) was confirmed the stability of Pb–TiO2 NPs. Antibacterial studies revealed that bare Pb–TiO2 NPs (20 μg/mL) did not exhibit significant antibacterial activity while combination of TCH + Pb–TiO2 NPs considerably increased the inhibition of E. coli biofilm evidenced by CLSM and SEM analysis. Further, Pb–TiO 2 NPs (100 μg/mL) were found to be moderately toxic to cell line (NIH3T3), red blood cells (RBC), and egg embryos. Hence, this study concluded that <50 μg/mL of TiO 2 NPs can be mixed with antibiotics for enhanced antibacterial application thereby minimizing the AMR and the environmental toxicity. • TiO2 NPs synthesized using endophytic fungus Paraconiothyrium brasiliense (Pb). •Pb-TiO2 NPs exhibited the smaller size particles and high crystallinity. •Pb-TiO2 NPs substantially assisted to inhibit the anti-biofilm activity of antibiotic. •The higher concentration of Pb-TiO2 NPs has shown the toxic effects on egg embryo.