Multifaceted biomedical applications of biogenic titanium dioxide nanoparticles fabricated by marine actinobacterium Streptomyces vinaceusdrappus AMG31.

The biomass filtrate of marine actinobacterium, Streptomyces vinaceusdrappus AMG31, was utilized as a biocompatible and biocatalyst for titanium dioxide nanoparticles (TiO₂-NPs) synthesis. Characterization revealed well-dispersed, spherical structures with high crystallinity in the anatase phase, with sizes from 10 to 50 nm. The biosynthesized TiO₂-NPs demonstrated potent antioxidant activity with maximum DPPH and ABTS radical scavenging percentages of 94.6% and 88.2% at 1000 µg/ml, with IC₅₀ values of 11.1 and 14.36 µg/ml, respectively. TiO₂-NPs exhibited moderate wound healing activity with 66.6% wound closure compared to controls (62.6%) after 48 h. The hemocompatibility assessment revealed minimal hemolytic activity (1.9% at 1000 µg/ml) and modest anticoagulant effects in PT (14.2 s) and PTT (43 s) at 75 µg/ml. Moreover, TiO₂-NPs displayed selective cytotoxicity towards cancer cells (Caco-2 and PANC-1) with IC₅₀ values of 74.1 ± 0.7 and 71.04 ± 1.2 µg/ml, respectively, while showing lower toxicity towards normal WI38 cells (IC₅₀ 153.1 ± 1.01 µg/ml). The nanoparticles demonstrated significant antidiabetic potential through α-amylase and α-glucosidase inhibition (IC₅₀ 69.3 and 40.81 µg/ml, respectively). Notably, TiO₂-NPs exhibited potent antibacterial activity against Gram-positive bacteria, particularly Enterococcus faecalis (37 ± 0.1 mm inhibition zone vs. 28 ± 0.1 mm for gentamicin) and Gram-negative bacteria, especially E. coli (29 ± 0.1 mm vs. 22 ± 0.2 mm for gentamicin), with low MIC/MBC values (12.5/25 µg/ml for Gram-positive and 6.25/12.5 µg/ml for E. coli). The nanoparticles demonstrated superior antifungal activity compared to fluconazole against Penicillium glabrum (45 ± 0.1 mm vs. 38 ± 0.1 mm), Aspergillus niger (37 ± 0.2 mm vs. 36 ± 0.1 mm), and Candida albicans (30 ± 0.3 mm vs. 26 ± 0.3 mm). Furthermore, TiO₂-NPs showed remarkable antibiofilm activity against bacterial (90.8-98.2% inhibition) and fungal (97.3% inhibition for C. albicans) biofilms at 75% MBC/MFC concentrations. The actinobacterial TiO₂-NPs' biological activity profile, in conjunction with their biocompatibility, selective cytotoxicity, and minimal hemolytic activity, positions the actinobacterial TiO₂-NPs as promising candidates for various biomedical applications.