Preparation Of Thermo-responsive Biomaterials And Its Study On Cell Culture And Isolation

With the development of Tissue Engineering, scientists have achieved many progresses in this field. But there are still many challenges faced. The scientists are confused by the situation that the enzyme will impair or destroy some cell function Okano et al have developed to recover cell by using the N-isopropylacrylamide (NIPAAm) that has the temperature responsive. This study was based on the biomimetic engineering. The Chitosan (CS) and NIPAAm were applied to prepare the membrane used in the Tissue Engineering and hope it could detach cell sheet from the cultured surface without enzyme but only by changing the temperature.The paper used l-Ethyl-3- (3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) as a coupling agent, and N, N, N', N'-Tetramethylenediamine (TEMED) as accelerator to prepare the macromer CS-AAc by reacting the Acrylic acid (AAc) with CS with the Degree of deacetylation being 85%. Then, the P (CS-AAc-NIPAAm) membranes with different ratio were prepared through copolymerizing CS-AAc with NIPAAm. The FTIR and XPS proved the structure and properties of macromer and P (CS-AAc-NIPAAm) hydrogel. FTIR shows that the new compound comes from CS-AAc and the featured -CONH belongs to NIPAAm appearing in the P (CS-AAc-NIPAAm). Results from XPS got further confirmation about structure. By the contact angle test, the membrane showed the transference between hydrophobic and hydrophilic static along with temperature changed. Moreover, the lower critical solution temperature (LCST) was checked by the P (CS-AAc-NIPAAm) hydrogel. The LCST of hydrogel is 28.5℃, lower than the PNIPAAm hydrogel, while it can decrease with an increase in CS.In the UV grafting experiment, AAm and NIPAAm are grafted to TCPs and the new structure of TCPs surface was identified by FTIR and XPS. The result showed that the AAm and NIPAAm are grafted on the surface of TCPs as design.In cell culture test, L929 and Hep-G2 are cultured on the P (CS-AAc-NIPAAm) membrane and TCPs, respectively. The micrograph from SEM indicates the cell adhere well on the membrane and begin to grow several days. And when the temperature decrease, the P (CS-AAc-NIPAAm) membrane change to the hydrophilic one and the cell began to isolate. This step protects the cell function well. This study broadens the investigation of biomaterials used in vitro and can be used as a background of thermo-responsive biomaterials in Tissue Engineering.