NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences #05-01, National University of Singapore, 28 Medical Drive, 117456, Singapore.
ACS Nano. 2011 Sep 27;5(9):7334-41. doi: 10.1021/nn202190c. Epub 2011 Jul 29.
The culture of bone marrow derived mesenchymal stem cells (MSCs), as well as the control of its differentiation toward different tissue lineage, is a very important part of tissue engineering, where cells are combined with artificial scaffold to regenerate tissues. Graphene (G) and graphene oxide (GO) sheets are soft membranes with high in-plane stiffness and can potentially serve as a biocompatible, transferable, and implantable platform for stem cell culture. While the healthy proliferation of stem cells on various carbon platforms has been demonstrated, the chemical role of G and GO, if any, in guiding uncommitted stem cells toward differentiated cells is not known. Herein, we report that the strong noncovalent binding abilities of G allow it to act as a preconcentration platform for osteogenic inducers, which accelerate MSCs growing on it toward the osteogenic lineage. The molecular origin of accelerated differentation is investigated by studying the binding abilities of G and GO toward different growth agents. Interestingly, differentiation to adipocytes is greatly suppressed on G because insulin, which is a key regulator for the synthesis of fatty acids, is denatured upon π-π adsorption on G; in contrast, GO does not interfere with adipogenesis due to electrostatic binding with insulin. The different binding interactions and their subsequent influence on stem cell growth and differentiation are ascribed to different degrees of π-π stacking and electrostatic and hydrogen bonding mediated by G and GO.
骨髓间充质干细胞（MSCs）的培养及其向不同组织谱系的分化控制是组织工程的一个非常重要的部分，在组织工程中，细胞与人工支架结合以再生组织。石墨烯（G）和氧化石墨烯（GO）片是具有高面内刚度的软膜，它们有可能作为生物相容性、可转移和可植入的干细胞培养平台。虽然已经证明了各种碳平台上干细胞的健康增殖，但 G 和 GO 的化学作用（如果有的话）是否可以指导未分化的干细胞向分化细胞方向发展尚不清楚。在此，我们报告说，G 的强非共价结合能力使其可以作为成骨诱导剂的预浓缩平台，从而加速生长在其上的间充质干细胞向成骨谱系分化。通过研究 G 和 GO 对不同生长因子的结合能力，研究了加速分化的分子起源。有趣的是，由于胰岛素在 G 上发生π-π吸附而变性，因此它是合成脂肪酸的关键调节剂，因此在 G 上分化为脂肪细胞受到极大抑制；相比之下，GO 不会干扰脂肪生成，因为它与胰岛素之间存在静电结合。不同的结合相互作用及其随后对干细胞生长和分化的影响归因于 G 和 GO 介导的不同程度的π-π堆积以及静电和氢键相互作用。
