Department of Geriatric Dentistry, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology, Peking University , Beijing 100081, China.
CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
ACS Nano. 2017 Jun 27;11(6):5915-5924. doi: 10.1021/acsnano.7b01661. Epub 2017 Jun 8.
Control of stem cell behaviors at solid biointerfaces is critical for stem-cell-based regeneration and generally achieved by engineering chemical composition, topography, and stiffness. However, the influence of dynamic stimuli at the nanoscale from solid biointerfaces on stem cell fate remains unclear. Herein, we show that electrochemical switching of a polypyrrole (Ppy) array between nanotubes and nanotips can alter surface adhesion, which can strongly influence mechanotransduction activation and guide differentiation of mesenchymal stem cells (MSCs). The Ppy array, prepared via template-free electrochemical polymerization, can be reversibly switched between highly adhesive hydrophobic nanotubes and poorly adhesive hydrophilic nanotips through an electrochemical oxidation/reduction process, resulting in dynamic attachment and detachment to MSCs at the nanoscale. Multicyclic attachment/detachment of the Ppy array to MSCs can activate intracellular mechanotransduction and osteogenic differentiation independent of surface stiffness and chemical induction. This smart surface, permitting transduction of nanoscaled dynamic physical inputs into biological outputs, provides an alternative to classical cell culture substrates for regulating stem cell fate commitment. This study represents a general strategy to explore nanoscaled interactions between stem cells and stimuli-responsive surfaces.
控制干细胞在固-液界面的行为对于基于干细胞的再生至关重要，通常可以通过工程化学组成、形貌和刚度来实现。然而，固体生物界面上纳米尺度动态刺激对干细胞命运的影响尚不清楚。本文表明，聚吡咯（Ppy）阵列在纳米管和纳米尖端之间的电化学转换可以改变表面附着力，这可以强烈影响机械转导的激活并指导间充质干细胞（MSCs）的分化。通过无模板电化学聚合制备的 Ppy 阵列可以通过电化学氧化/还原过程在高粘附性的疏水性纳米管和低粘附性的亲水性纳米尖端之间可逆切换，从而在纳米尺度上实现与 MSCs 的动态附着和脱附。Ppy 阵列对 MSCs 的多循环附着/脱附可以激活细胞内机械转导并独立于表面刚度和化学诱导进行成骨分化。这种智能表面将纳米级动态物理输入转化为生物输出，为调节干细胞命运提供了一种替代传统细胞培养底物的方法。本研究代表了一种探索干细胞与刺激响应表面之间纳米级相互作用的通用策略。
