中文摘要：

近年来，鉴于心肌组织独有的电生理特性，应用导电纳米材料作为细胞支架开展心肌组织工程研究取得明显进展．碳纳米管材料具有良好的力学性能和导电特性，前期研究表明，其具有促进新生鼠心肌细胞中未成熟心肌细胞增殖与成熟心肌细胞进一步发育的作用，但尚未见碳纳米管材料对棕色脂肪来源的心脏干细胞（CSCs）生物学特性影响的研究报道．为此，本研究首先采用凝胶-溶胶法制备了羧基化多壁碳纳米管和聚甲基丙烯酸甲酯 （MWNTs/PMMA）薄膜，并通过一系列细胞学、免疫细胞化学及电镜检测方法，系统评价了MWNTs/PMMA薄膜对大鼠棕色脂肪CSCs活力、增殖能力及向心肌分化效率的影响．研究发现，与明胶材料相比，MWNTs/PMMA薄膜对棕色脂肪CSCs活力、增殖能力有明显促进作用，并且明显增强其向心肌细胞分化的能力，分化的心肌细胞具有明显可见的肌管结构，并且表达介导细胞间电化学传导的缝隙连接蛋白connexin43．此外，超微结构观察发现碳纳米管与细胞膜间及细胞与细胞之间可直接形成紧密连接，调控细胞行为．本研究首次探讨了碳纳米管导电材料对棕色脂肪CSCs生物学特性影响的规律，证实碳纳米管导电材料具有良好的促心肌细胞分化作用．作为一种新型导电纳米材料，碳纳米管在心肌组织工程研究中具有良好的应用前景，未来有望在心肌组织体外构建及心肌梗死治疗性应用中发挥潜在的价值．

英文摘要：

Considering the structure and electrophysiological properties of native myocardium, significant progress has been made in cardiac tissue engineering based on nano-conductive materials. Carbon nanotubes possess the good mechanical and electrical properties and previous study have showed carbon nanotubes can promote cardiac cells adhesion, proliferation and maturation, and enhance cell-cell electrical coupling. However, cell behavior of carbon nanotubes on brown adipose-derived cardiac stem cells （CSCs） has not been investigated. Here, we first prepared multiple-walled carbon nanotubes （MWCNTs） / polymethylmethacrylate （PMMA） thin film according to the reported study. And then, we explored the influences of MWNTs/PMMA thin films on cell viability, proliferation and cardiac differentiation of brown adipose-derived CSCs were evaluated. We demonstrated MWNTs/PMMA thin films has no obvious effect on cell viability and proliferation of brown adipose CSCs compared to those on gelatin thin film. Furthermore, we observed brown adipose CSCs on MWNTs/PMMA thin films exhibited significantly higher amounts of α-actinin and connexin43. By transmission electron microscopy, we found that carbon nanotubes were in direct contact with cell membranes and regulated cell behavior. We first explored the influence of carbon nanotubes on brown adipose-derived CSCs and found that carbon nanotubes promoted the cardiac differentiation of brown adipose-derived CSCs. This study may be benefit to promote the therapeutic application of carbon nanotubes in myocardial infarction.