Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
J Biomed Nanotechnol. 2013 Sep;9(9):1532-9. doi: 10.1166/jbn.2013.1650.
Polypyrrole (PPy), as an electrical conductive polymer, has been widely investigated in biomedical fields. In this study, PPy membrane at nanoscale was electrically deposited on indium-tin oxide glass slide with sodium p-toluenesulfonate as supporting electrolyte. Electropolymerization of PPy was performed under a constant 800 mV voltage for 10 seconds. Chemical compositions and morphology were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the nanoscaled PPy particles distributed uniformly and the average diameter of PPy particles was 62 nm. Since bone cells can respond to both electrical and mechanical stimulation in vivo, pre-osteoblasts MC3T3-E1 cells were cultured ort nanostructured PPy membrane under the combined electrical and mechanical stimulation. The nano-PPy membrane was conducive to transferring uniform electrical stimulation and applying steady mechanical stimulation. It is suggested that the combined stimulation did not affect cells morphologies significantly. However, cell proliferation tested by MTT, alkaline phosphatase activities, and gene expression of Collagen-I indicated that combined stimulation can enhance the proliferation and differentiation of MC3T3-E1 cells more efficiently than single electrical stimulation or single mechanical stimulation. The combined stimulation through a nano-PPy membrane may provide a highly potential stimulated method in bone tissue engineering.
聚吡咯（PPy）作为一种导电聚合物，已在生物医学领域得到广泛研究。本研究采用对甲苯磺酸钠作为支持电解质，在纳秒级尺度上将 PPy 电沉积在氧化铟锡玻璃载玻片上。在 800 mV 的恒定电压下进行 10 秒的 PPy 电聚合。采用傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）对化学组成和形貌进行了表征。结果表明，纳米级 PPy 颗粒均匀分布，PPy 颗粒的平均直径为 62nm。由于骨细胞在体内可以同时响应电刺激和机械刺激，因此在电和机械联合刺激下，将成骨前体细胞 MC3T3-E1 培养在纳米结构的 PPy 膜上。纳米 PPy 膜有利于传递均匀的电刺激和施加稳定的机械刺激。结果表明，联合刺激对细胞形态的影响不显著。然而，通过 MTT 测试、碱性磷酸酶活性和 Collagen-I 基因表达表明，与单一电刺激或单一机械刺激相比，联合刺激更有效地促进了 MC3T3-E1 细胞的增殖和分化。通过纳米 PPy 膜的联合刺激可能为骨组织工程提供一种很有前途的刺激方法。
