新型温敏性中空纤维膜的制备与表征

采用自由基聚合方法对中空纤维膜（hollow fiber membranes，HFMs）进行了N-异丙基丙烯酰胺（NIPAAm）的接枝聚合，制备了一系列PNIPAAm-g-HFMs，同时考察了成纤维细胞在PNIPAAm-g-HFMs表面的培养与降温脱附情况。傅里叶红外光谱和元素分析结果表明PNIPAAm成功地在中空纤维膜上接枝聚合。动态接触角分析结果显示，当温度降至LCST以下，PNIPAAm-g-HFMs表面接触角明显降低；蛋白黏附测定结果进一步证实了当温度发生改变时，PNIPAAm-g-HFMs表面呈现亲疏水性质变化，即具有温敏性。37℃时，成纤维细胞在HFMs-0.005，HFMs-0.01和HFMs-0.05表面均能正常黏附、铺展与增殖；而HFMs-0.2不适宜细胞的黏附与生长。降温孵育后，黏附于PNIPAAm-g-HFMs表面的细胞发生明显的形态变化并从其表面发生脱附，细胞脱附率高达90%以上。以上实验结果表明，PNIPAAm-g-HFMs具有良好的温敏性，可实现细胞的降温脱附，可与生物反应器相结合用于贴壁型细胞的大规模扩增与降温收获。

Preparation and characterization of novel thermo-responsivehollow fiber membranes

Owing to the large scale area-to-volume ratio involved, hollow fiber membranes (HFMs) provide a tremendous amount of surface area for cell adhesion. Therefore, HFMs are widely used for large-scale expansion of cells. Traditionally, trypsinization is empolyed to harvest adhered cells from the surface of HFMs. However, this proteolytic enzyme treatment will destroy cell viability and function. Therefore, this study prepared a serious poly(N-isopropylacrylamide) (PNIPAAm) grafted HFMs (PNIPAAm-g-HFMs) with different grafted amounts, and the fibroblasts culture and detachment from PNIPAAm-g-HFMs with temperature reduction was also investigated. ATR-FTIR and elemental analysis results indicated that the PNIPAAm was covalently grafted on HFMs successfully via free radical polymerization in the presence of cerium (Ⅳ). Dynamic contact angle measurements showed that the surface contact angle of water on PNIPAAm-g-HFMs decreased significantly when the temperature dropped below LCST. Additionally, the protein adhesion assay results further confirmed that PNIPAAm-g-HFMs exhibited thermo-responsive property, namely hydrophilic-hydrophobic phase transition with temperature changed. MEFs adhered, spread and grew well on the surface of PNIPAAm-grafted HFMs except HFMs-0.2 at 37℃. In addition, the experiment of cell detachment showed that the cell can be released from PNIPAAm-g-HFMs with decreasing temperature and detachment efficiencies were above 90%. In conclusion, the PNIPAAm-g-HFMs with thermo-responsive property can be an attractive candidate for cell large-scale expansion and cell detachment with temperature reduction.