Effect of Pt/C addition to TiO2 films on adhesion and rapid light-induced detachment of mammalian cell cultures

Light-induced cell detachment on the substrate of TiO 2 nanodots has been proved to be a safe and attractive method for cell harvesting in tissue engineering. In order to improve the cell release efficiency, bioinert platinum with excellent charge transport loading in biocompatible graphite was prepared. 20   wt.% Pt/C powder showing excellent electrical, chemical and bioactive properties was incorporated to a TiO 2 system. We investigated the biocompatibility of Pt/C–TiO 2 composite films with different amounts of Pt/C with C/tetrabutyl titanate molar ratio varying from 0 to 0.42. The adhesion and proliferation rates of pre-osteoblastic MC3T3-E1 cells (mouse calvaria-derived) on the films prepared with the highest C/TiO 2 molar ratio are higher than that of the pure TiO 2 and other films, indicating a Pt/C dose-dependent effect. It is shown that the detachment efficiency of MC3T3-E1 cells depends on Pt/C amount and UV illumination time. Moreover, films prepared with C/tetrabutyl titanate molar ratio of 0.42 showed 93% cell detachment ratio within 5   min of UV illumination, while bare TiO 2 films only reached 75%, indicating an improved cell release efficiency by the incorporation of Pt/C. However, an interesting phenomenon was found that longer illumination time showed lower detachment ratios to some extent, which is contrary to our previous work. It is believed that this work presents the improved cell detachment efficiency by the incorporation of Pt/C.