Fabrication of TiO2 Nanoparticles with High Colloidal Stability through Surface Modification via Biocompatible Block
Atsushi Harada1, Azusa Inoue1, Yukiya Kitayama1
1Department of Applied Chemistry, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
Abstract:
Titanium dioxide nanoparticles (TiO2 NPs) possess unique physicochemical properties that make them attractive for various applications. However, poor colloidal stability under physiological conditions limits biomedical applications. To address this issue, we synthesized poly(oligoethylene glycol methacrylate) (POEGMA) and POEGMA-block-poly(2-methacryloyl oxyethyl phosphoryl choline) (POEGMA-block-PMPC) polymers bearing phosphonic acid end groups for anchoring to the TiO2 surfaces. Dynamic light scattering revealed that the colloidal stability of TiO2 NPs in phosphate-buffered saline improved with increasing molecular weights of the modified polymers. Furthermore, heat treatment after POEGMA-block-PMPC modification further improved the colloidal stability, most likely because of changes in the coordination structure between phosphonic acid and TiO2. Importantly, the block copolymer-modified TiO2 NPs retained their function as sonosensitizers after heating, enabling their potential in biomedical applications such as sonodynamic therapy.
