[Strategies to choose scaffold materials for tissue engineering].

Current therapies of organ failure or a wide range of tissue defect are often not ideal. Transplantation is the only effective way for long time survival. But it is hard to meet huge patients demands because of donor shortage, immune rejection and other problems. Tissue engineering could be a potential option. Choosing a suitable scaffold material is an essential part of it. According to different sources, tissue engineering scaffold materials could be divided into three types which are natural and its modified materials, artificial and composite ones. The purpose of tissue engineering scaffold is to repair the tissues or organs damage, so could reach the ideal recovery in its function and structure aspect. Therefore, tissue engineering scaffold should even be as close as much to the original tissue or organs in function and structure. We call it "organic scaffold" and this strategy might be the drastic perfect substitute for the tissues or organs in concern. Optimized organization with each kind scaffold materials could make up for biomimetic structure and function of the tissue or organs. Scaffold material surface modification, optimized preparation procedure and cytosine sustained-release microsphere addition should be considered together. This strategy is expected to open new perspectives for tissue engineering. Multidisciplinary approach including material science, molecular biology, and engineering might find the most ideal tissue engineering scaffold. Using the strategy of drawing on each other strength and optimized organization with each kind scaffold material to prepare a multifunctional biomimetic tissue engineering scaffold might be a good method for choosing tissue engineering scaffold materials. Our research group had differentiated bone marrow mesenchymal stem cells into bile canaliculi like cells. We prepared poly(L-lactic acid)/poly(ε-caprolactone) biliary stent. The scaffold's internal played a part in the long-term release of cytokines which mixed with sustained-release nano-microsphere containing growth factors. What's more, the stent internal surface coated with glue/collagen matrix mixing layer containing bFGF and EGF so could supplying the early release of the two cytokines. Finally, combining the poly(L-lactic acid)/poly(ε-caprolactone) biliary stent with the induced cells was the last step for preparing tissue-engineered bile duct. This literature reviewed a variety of the existing tissue engineering scaffold materials and briefly introduced the impact factors on the characteristics of tissue engineering scaffold materials such as preparation procedure, surface modification of scaffold, and so on. We explored the choosing strategy of desired tissue engineering scaffold materials.

[Optimization of the method for isolating and culturing rat mesenchymal stem cells].

OBJECTIVE: To optimize the protocols for isolation and culture of mesenchymal stem cells from rat bone marrow (BMSCs). METHODS: BMSCs were isolated by adherence to plastic with frequent medium change and reduced trypsinization time. The cell growth curves were drawn and the surface markers of BMSCs were detected by flow cytometry. The cells were induced to differentiate into osteogenic, adipogenic, hepatic and cholic lineages. RESULTS: The cells isolated using this method were positive for CD29, CD44, and CD90 and negative for the hematopoietic surface markers CD45. The osteogenic and adipogenic differentiation of the BMSCs was verified by alkaline phosphatase staining, Alizarin red staining and Oil red staining. The cell subcultures up to passage 10 maintained capacities of differentiation into osteogenic and adipogenic lineages. The BMSCs induced with sequential addition of growth factors, cytokines and hormones differentiated into cells expressing hepatocyte- and cholangiocyte-specific markers. CONCLUSION: The optimized method allows efficient isolation of homogenous populations of MSCs from rat bone marrow, which can be induced into multiple cell lineages.

An in situ electrochemical detection method of cell viability.

An in situ electrochemical method of cell viability, which integrated cell culture, pretreatment and detection in a cell culture dish, was developed. The method significantly improved the electrochemical response of cells, simplified the operation process, reduced the experiment time, avoided the use of trypsin, and was applied in the study of the effectiveness of antitumor drugs on tumor suppression.