BACKGROUND: Polypyrrole (PPy) has been widely applied in biomedical fields due to its special electronic property. Past 20 years, there are an increasing number of studies on the application of PPy as a potentially electrically addressable tissue/cell support substrate for tissue/cell regeneration.OBJECTIVE: To overall review the application of PPy in tissue engineering field, and to provide a new approach for the research and development of medical biomaterials.METHODS: Pubmed and Chinese biomedicine literature database were searched using key word of "polypyrrole" for documents published between 1990 and 2010. Literatures related to application of PPy in tissue engineering field were included, and the repetitive articles were excluded.RESULTS AND CONCLUSION: Totally 762 papers were searched by computer, according to the inclusive and exclusive criteria, 51 literature were reviewed. Currently, PPy has been widely used in the fields of cardiovascular tissue engineering, bone and muscle tissue engineering, as well as skin tissue engineering. Application of PPy and PPy-based biomaterials hold great potential in development of novel biomedical materials applied in tissue engineering due to their versatile functionality and superior biocompatibility.

Summary: The regulation of hypoxic response elements on the expression of vascular endothelial growth factor (VEGF) gene transfected to primary cultured rat skeletal myoblasts under hypoxic environment was investigated, pEGFP-C3-9HRE-CMV-VEGF vector was constructed with molecular biology technique and transfected to primary cultured rat skeletal myoblasts by lipofectamine in vitro. Gene expression of transfected myoblasts was detected by RT-PCR, Western blot and fluorescence microscope under different oxygen concentrations and different hypoxia time. The results showed that in hypoxia group, the VEGF gene bands were seen and with the decrease of oxygen concentrations and prolongation of hypoxia time, the expression of VEGF mRNA was obviously increased.Under hypoxic environment, the expression of VEGF protein in the transfected myoblasts was significantly increased. EGFP was expressed only under hypoxic environment but not under normoxic environment. It was concluded that hypoxia promoter could be constructed with HRE and regulate the expression of VEGF gene under hypoxic and normoxic environment, which could enhance the reliability of gene therapy.