The Cultivation And Harvest Of Bone Mesenthymal Stem Cells On PVDF-g-PNIPAAm Thermo-Sensitive Membrane

Currently, the enzymatic treatment is widely used in the harvest of mesenthymal stem cells (MSCs), which seperates and scatters the junction between cell and substrate materials or cell, and extracellular matrix are damaged to some extent, thus produces an influence on application of MSCs in tissue engineering and medical reseach. A temperature-responsive polymer surface of Poly (N-isopropylacrylamide) (PNIPAAm) can be used to culture and harvest the stem cells by adjusting temperature, which provides an effective solution for the mild harvest of MSCs.In this study, three groups copolymer PNIPAAm-grafted poly(vinylidene fluoride) (PVDF-g-PNIPAAm) of different grafting ratios (2.75%,6.25%and 12.2%) was synthesized via alkli-treatment and radical copolymerization. The 1H-Nuclear magnetic resonance (1HNMR) spectroscopy and Fourier transform infrared spectroscopy (FTIR) showed that the PNIPAAm was grafed to the PVDF chain successfully. The flat sheet membranes prepared via phase inversion method, respectively labelled as M41, M23 and M23. were characterized by scanning electron microscope (SEM) and water contact angle tester, which indicated that the membrane surfaces with pore structure took on a weak hydrophilicity as well as thermosensitive. Then, the rat bone marrow mesenthymal stem cells (BMSCs) were isolated via the whole bone marrow culture method, and identified in morphology, cell surface antigen, colony-forming ability and multi-directional differentiation potential. As a result, the cell presented a spindle morphology like fibroblasts, of which the expression ratio of CD34, CD29 and CD90 were 2.1%,94.0% and 92.6% respectively; the colony-forming efficiency was 1.7% with the density of 500cel]s/cm2 onto six-wells plates for 2 weeks, revealing that the SD rat BMSCs possess certain proliferation activity; The BMSCs could be inducued into adipocytes, osteoblasts and chondrocytes. MTT assay and detachment experient revealled that BMSCs could adhere and grow on PVDF-g-PNIPAAm membranes, but cell vitality was lower than that on tissue cell plates, the detachment efficiency was all above 75%. Induction differentiation experiment indicated that the BMSCs detached from M41 still maintained the ability of differentiation into adipocytes and osteoblasts.