Abstract:

BACKGROUND: In the tissue engineering studies, the common method of cell detachment is trypsinization. However, this method may decrease cell activity by breaking the extracellular matrix proteins. Therefore, it is important to develop a new cell detachment method which can avoid the damage from trypsinization.
OBJECTIVE: Based on that poly N-isopropylacrylamide (PNIPAAm) could alter its hydrophobic property with the change of temperature, this study aimed to develop a novel method which can control cell detachment by simply changing the temperature.
METHODS: IPAAm was dissolved in isopropanol with final concentration of 55% (w/v). IPAAm solution was evenly laid on the surface of TCPS dish, and PNIPAAm was then covalently grafted on the TCPS dish surface by electron beam irradiation. The microstructure of the surface of TCPS dish was observed by atomic force microscopy (AFM) before and after PNIPAAm grafted. Water contact angle was determined by sessile drop method. And an inverted phase contrast microscope was used to observe and evaluate the cell detachment ability of PNIPAAm grafted TCPS dish by subjecting the same dish to different temperatures.
RESULTS AND CONCLUSION: AFM images showed that a thin and compact PNIPAAm layer formed on the TCPS dish surface. In the water contact angle test, there was no statistic difference between PNIPAAm grafted and ungrafted surfaces at 37 ℃, and the water contact angle of PNIPAAm grafted surfaces was lower than that of ungrafted surface at 20 ℃. The cells adhered to the surface of the PNIPAAm grafted TCPS dish at 37 ℃, which would be detached at 20 ℃.It was successful to control cell detachment by simply changing the temperature with PNIPAAm grafted TCPS dish, and it would be promising to be applied in tissue engineering.