Waiwijit Uraiwan, Maturos Thitima, Pakapongpan Saithip, Phokharatkul Ditsayut, Wisitsoraat Anurat, Tuantranont Adisorn
Thai Organic and Printed Electronics Innovation Center, National Electronics and Computer Technology Center (NECTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand.
Nanoelectronics and MEMS Laboratory, National Electronics and Computer Technology Center (NECTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand.
J Biomater Appl. 2016 Aug;31(2):230-40. doi: 10.1177/0885328216656477. Epub 2016 Jun 29.
Recently, three-dimensional graphene interconnected network has attracted great interest as a scaffold structure for tissue engineering due to its high biocompatibility, high electrical conductivity, high specific surface area and high porosity. However, free-standing three-dimensional graphene exhibits poor flexibility and stability due to ease of disintegration during processing. In this work, three-dimensional graphene is composited with polydimethylsiloxane to improve the structural flexibility and stability by a new simple two-step process comprising dip coating of polydimethylsiloxane on chemical vapor deposited graphene/Ni foam and wet etching of nickel foam. Structural characterizations confirmed an interconnected three-dimensional multi-layer graphene structure with thin polydimethylsiloxane scaffold. The composite was employed as a substrate for culture of L929 fibroblast cells and its cytocompatibility was evaluated by cell viability (Alamar blue assay), reactive oxygen species production and vinculin immunofluorescence imaging. The result revealed that cell viability on three-dimensional graphene/polydimethylsiloxane composite increased with increasing culture time and was slightly different from a polystyrene substrate (control). Moreover, cells cultured on three-dimensional graphene/polydimethylsiloxane composite generated less ROS than the control at culture times of 3-6 h. The results of immunofluorescence staining demonstrated that fibroblast cells expressed adhesion protein (vinculin) and adhered well on three-dimensional graphene/polydimethylsiloxane surface. Good cell adhesion could be attributed to suitable surface properties of three-dimensional graphene/polydimethylsiloxane with moderate contact angle and small negative zeta potential in culture solution. The results of electrochemical study by cyclic voltammetry showed that an oxidation current signal with no apparent peak was induced by fibroblast cells and the oxidation current at an oxidation potential of +0.9 V increased linearly with increasing cell number. Therefore, the three-dimensional graphene/polydimethylsiloxane composite exhibits high cytocompatibility and can potentially be used as a conductive substrate for cell-based electrochemical sensing.
近年来，三维石墨烯互连网络因其高生物相容性、高导电性、高比表面积和高孔隙率，作为一种用于组织工程的支架结构而备受关注。然而，独立的三维石墨烯由于在加工过程中易于分解，表现出较差的柔韧性和稳定性。在这项工作中，通过一种新的简单两步法将三维石墨烯与聚二甲基硅氧烷复合，以提高结构的柔韧性和稳定性，该方法包括在化学气相沉积的石墨烯/泡沫镍上浸涂聚二甲基硅氧烷以及对泡沫镍进行湿法蚀刻。结构表征证实了具有薄聚二甲基硅氧烷基架的互连三维多层石墨烯结构。该复合材料被用作L929成纤维细胞培养的底物，并通过细胞活力（alamar蓝测定法）、活性氧生成和纽蛋白免疫荧光成像评估其细胞相容性。结果表明，三维石墨烯/聚二甲基硅氧烷复合材料上的细胞活力随培养时间的增加而增加，与聚苯乙烯底物（对照）略有不同。此外，在3-6小时的培养时间内，在三维石墨烯/聚二甲基硅氧烷复合材料上培养的细胞产生的活性氧比对照少。免疫荧光染色结果表明，成纤维细胞表达粘附蛋白（纽蛋白）并在三维石墨烯/聚二甲基硅氧烷表面良好粘附。良好的细胞粘附可归因于三维石墨烯/聚二甲基硅氧烷在培养液中具有适度接触角和小负zeta电位的合适表面性质。循环伏安法的电化学研究结果表明，成纤维细胞诱导了无明显峰的氧化电流信号，在+0.9V氧化电位下的氧化电流随细胞数量的增加而线性增加。因此，三维石墨烯/聚二甲基硅氧烷复合材料表现出高细胞相容性，并有可能用作基于细胞的电化学传感的导电底物。
