Multifaceted biomedical applications of biogenic titanium dioxide nanoparticles fabricated by marine actinobacterium Streptomyces vinaceusdrappus AMG31
Ahmed Ghareeb, Amr Fouda, Rania Kishk, Waleed M. El Kazzaz
Abstract
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.