Okano T, Yamada N, Okuhara M, Sakai H, Sakurai Y
Institute of Biomedical Engineering, Tokyo Women's Medical College, Japan.
Biomaterials. 1995 Mar;16(4):297-303. doi: 10.1016/0142-9612(95)93257-e.
Poly(N-isopropylacrylamide) (PIPAAm), exhibiting a lower critical solution temperature (LCST) at 25 degrees C in physiological phosphate buffered saline solution (pH 7.4) and at 32 degrees C in pure water, was grafted onto the surfaces of commercial polystyrene cell culture dishes. This PIPAAm-grafted surface exhibited hydrophobic surface properties at temperatures over the LCST and hydrophilic surface properties below the LCST. Endothelial cells and hepatocytes attached and proliferated on PIPAAm-grafted surfaces at 37 degrees C, above the LCST. The cultured cells were readily detached from these surfaces by lowering the incubation temperature without the usual damage associated with trypsinization. In this case, the optimum temperature for cell detachment was 10 degrees C for hepatocytes and 20 degrees C for endothelial cells. Cell detachment was partially inhibited by sodium azide treatment, suggesting that cell metabolism directly affects cell detachment. Morphological changes of the adherent cells during cell detachment experiments indicated further involvement of active cellular metabolic processes. Cells detached from hydrophobic-hydrophilic PIPAAm surfaces not only via reduced cell-surface interactions caused by the spontaneous hydration of grafted PIPAAm chains, but also by active cell morphological changes which were a function of cell metabolism.
聚（N-异丙基丙烯酰胺）（PIPAAm）在生理磷酸盐缓冲盐水溶液（pH 7.4）中于25℃以及在纯水中于32℃时表现出较低临界溶液温度（LCST），它被接枝到商用聚苯乙烯细胞培养皿的表面。这种接枝了PIPAAm的表面在温度高于LCST时呈现疏水表面性质，而在低于LCST时呈现亲水表面性质。内皮细胞和肝细胞在37℃（高于LCST）时附着并在接枝了PIPAAm的表面上增殖。通过降低孵育温度，培养的细胞很容易从这些表面脱离，而不会产生与胰蛋白酶消化相关的常见损伤。在这种情况下，肝细胞的最佳细胞脱离温度为10℃，内皮细胞为20℃。叠氮化钠处理部分抑制了细胞脱离，这表明细胞代谢直接影响细胞脱离。细胞脱离实验期间贴壁细胞的形态变化表明活跃的细胞代谢过程进一步参与其中。从疏水 - 亲水PIPAAm表面脱离的细胞不仅是通过接枝的PIPAAm链的自发水合导致细胞 - 表面相互作用减少，而且还通过作为细胞代谢功能的活跃细胞形态变化。
