A facile synthesis of polydopamine/TiO2 composite films for cell sheet harvest application.

This study presents a convenient and versatile way to prepare functionalized composite polydopamine/titanium dioxide (PDA/TiO2) film on polystyrene (PS). First, polystyrene substrate was immersed in dopamine chloride solution, and then collosol containing TiO2 and water was spun on it, to produce uniform, continuous PDA/TiO2 composite films. The thickness of film was controllable by adjustment of the spin speed. It was found that the films were strongly adhered on the PS substrate, with peel strength and shear strength of 2.78 MPa and 37.78 MPa, respectively. After 20 min of ultraviolet (365 nm) illumination, over 90% of fibroblasts and 77% of osteoblasts detached from the PDA/TiO2 composite film. Additionally, the detached cells showed good viability, allowing further culture and applications. This preparation method could be widely applied for cell and cell sheet harvesting directly from PS-based culture wares.

SiO2/TiO2 Nanocomposite Films on Polystyrene for Light-Induced Cell Detachment Application.

Light-induced cell detachment shows much potential in in vitro cell culture and calls for high-performance light-responsive films. In this study, a smooth and dense SiO2/TiO2 nanocomposite thin film with thickness of around 250 nm was first fabricated on H2O2 treated polystyrene (PS) substrate via a low-temperature sol-gel method. It was observed that the film could well-adhere on the PS surface and the bonding strength became increasingly high with the increase of SiO2 content. The peeling strength and shear strength reached 3.05 and 30.02 MPa, respectively. It was observed the surface of the film could transform into superhydrophilic upon 20 min illumination of ultraviolet with a wavelength of 365 nm (UV365). In cell culture, cells, i.e., NIH3T3 and MC3T3-E1 cells, cultured on SiO2/TiO2 nanocomposite film were easily detached after 10 min of UV365 illumination; the detachment rates reached 90.8% and 88.6%, respectively. Correspondingly, continuous cell sheets with good viability were also easily obtained through the same way. The present work shows that SiO2/TiO2 nanocomposite thin film could be easily prepared on polymeric surface at low temperature. The corresponding film exhibits excellent biocompatibility, high bonding strength, and good light responses. It could be a good candidate for the surface of cell culture utensils with light-induced cell detachment property.