Poly(N-isopropylacrylamide)(PNIPAAm)-based thermo-responsive surfaces can switch their wettability(from wettable to non-wettable) and adhesion(from sticky to non-sticky) according to external temperature changes. These smart surfaces with switchable interfacial properties are playing increasingly important roles in a diverse range of biomedical applications; these controlling cell-adhesion behavior has shown great potential for tissue engineering and disease diagnostics. Herein we reviewed the recent progress of research on PNIPAAm-based thermo-responsive surfaces that can dynamically control cell adhesion behavior. The underlying response mechanisms and influencing factors for PNIPAAm-based surfaces to control cell adhesion are described first. Then, PNIPAAm-modified two-dimensional flat surfaces for cell-sheet engineering and PNIPAAm-modified three-dimensional nanostructured surfaces for diagnostics are summarized. We also provide a future perspective for the development of stimuli-responsive surfaces.
An approach was described to produce a wound area in vitro using laminar flow technique to selectively remove cells in micro fluidic channels. Cell migration which plays an important role in the process of wound healing can be observed dynamically by this method. In order to prove our system, we have studied its properties by injecting NIH-3T3 cells into main channel and added several reagents to observe the mediatory influence. The results reveal that fibroblast growth factor-2（FGF-2）, insulin-like growth factor 1（IGF-Ⅰ）, platelet-derived growth factor BB（PDGF-BB） and ascorbic acid（Vc） groups can promote cell migration compared with the control group. But the average migration distance was diminished in dexamethasone group. It can be concluded that this system can be used to analyze the process of wound healing.
XI Yan-liWANG Shu-taoSU BinHA QingNIU Feng-lanNIE Fu-qiang
