Effect of surface modification on the bioactivity of sol-gel TiO2-based nanomaterials

Abstract

BACKGROUND Surface composition of titanium dioxide (TiO2) nanoparticles strongly affects their biocompatibility and cytotoxicity. The appropriated functionalization of TiO2 nanoparticles leads to the improvement of these properties; while increasing biocompatibility allows the safety use of TiO2 nanoparticles, their cytotoxicity can be properly used in cancer therapy. RESULTS Amine functionalization of the sol–gel TiO2 nanoparticles was performed by in situ addition of -Gama- aminobutyric acid (GABA)-, and 1% mol of platinum (II) acetylacetonate. Fluoresceine isothiocyanate (FITC) was attached to the surface of the nanoparticles through amine-groups from GABA on the titanium dioxide surface. Nanoparticles obtained formed aggregates of around 100–300 nm. A strong and steady green-emission from labeled nanomaterials was observed. Transmission electron microscopy (TEM) showed that smaller particles (<100 nm) passed through the cellular membrane as they were observed within the cytoplasm and mitochondria. Activation of Caspase-3, a protein involved in apoptosis, was observed in treated cells, which agrees with terminal deoxynucleotidyl transferase dUTP nick end labeling assay results (TUNEL) where the highest DNA fragmentation was observed for Pt-TiO2-GABA nanomaterial. CONCLUSIONS TiO2 amino-functionalized nanoparticles were fluorescently labeled in a simple manner. The nanoparticles formed vesicles and activated a caspase-3 mediated mechanism to induce apoptosis. The addition of acetylacetone together with platinum promoted cell death. © 2016 Society of Chemical Industry