Analytical Sciences

Synthesis and Characterization of TiO₂ Nanoparticles: Applications in Research on the Interaction of Colloidal TiO₂ with Human Serum Albumin by Fluorescence Spectroscopy

Tao SUN,* Lusha LIU,* Yang SUN,* Chunlei TAN,* Fei YAO,* Xuhua LIANG,* Yan WANG,* Yuhao YANG,* Xiaoyun HU,** and Jun FAN*

*School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi’an, Shaanxi 710069, P. R. China
**Department of Physics, Northwest University, No. 229 Taibai North Road, Xi’an, Shaanxi 710069, P. R. China

Titanium dioxide (TiO₂) nanoparticles (NPs) are widely used as an important kind of biomaterials due to their large surface area, enhanced chemical reactivity and easy penetration into cells. Nano TiO₂ with pure anatase phase was successfully prepared by solvothermal method. Its particle size was about 21 nm, while the larger specific surface area of TiO₂ was 77.43 m²/g. The interaction of colloidal TiO₂ with human serum albumin was studied by using absorption spectra and fluorescence spectra. The apparent binding constants (K) were 345.780 × 10⁵, 4.376 × 10⁵, 0.035 × 10⁵ at 298, 303 and 308 K, respectively. In addition, the number of binding sites (n) was gradually decreased with the increase of temperature, which indicated that the quenching mechanism of albumin by colloidal TiO₂ was static fluorescence quenching process. Based on fluorescence resonance energy transfer, the energy transfer efficiency (E) and critical transfer distance (r₀) between donor (human serum albumin, HSA) and acceptor (colloidal TiO₂) were calculated to be 0.862 and 6.244 nm, which suggested that non-radiative energy transfer occurred between TiO₂ and HSA. Furthermore, the conformational changes of HSA were shown by synchronous fluorescence.

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