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.