State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China.
J Mater Chem B. 2020 Nov 11;8(43):9913-9920. doi: 10.1039/d0tb01968b.
Stem cells have attracted increasing research interest in the field of regenerative medicine due to their unique abilities to differentiate into multiple cell lineages. Label-free, real-time, and long-term monitoring for stem cell differentiation is requisite in studying directional differentiation and development mechanisms for tissue engineering applications, but a great challenge because of the rigorous demands for sensitivity, stability and biocompatibility of devices. In this article, a label-free and real-time monitoring approach using a zinc oxide (ZnO) nanorod field effect transistor (FET) is proposed to detect cell traction forces (CTFs) exerted by cells on underlying substrates. The ZnO nanorod FET with the approach of difference-frequency lock-in detection achieves high sensitivity, good stability, and excellent biocompatibility, by which real-time and long-term (over 20 days) monitoring of cellular mechanical changes in osteogenic differentiation of mesenchymal stem cells (MSCs) is successfully achieved. We also employ electrical impedance monitoring using microelectrode array chips and microscopic observation to investigate cell migration and nodular aggregation behaviors of MSCs in osteogenic differentiation. Various biochemical assays including alkaline phosphatase (ALP), osteopontin expression and alizarin red staining are utilized to verify osteogenic differentiation of MSCs. We propose a combination of cell traction force measurement, impedance measurement and microscopic observation to provide multimodal profiling of cell morphology, and cellular biomechanical and electrophysiological phenotypes, which can track cellular dynamics in stem cell development and help to deeply understand the mechanism of osteogenic differentiation.
干细胞因其独特的分化为多种细胞谱系的能力，在再生医学领域引起了越来越多的研究兴趣。在研究组织工程应用的定向分化和发育机制时，需要对干细胞分化进行无标记、实时和长期监测，但由于对设备的灵敏度、稳定性和生物相容性要求苛刻，这是一个巨大的挑战。在本文中，提出了一种使用氧化锌 (ZnO) 纳米棒场效应晶体管 (FET) 的无标记和实时监测方法，用于检测细胞对基底施加的细胞牵引力 (CTF)。通过差频锁定检测方法的 ZnO 纳米棒 FET 具有高灵敏度、良好的稳定性和优异的生物相容性，成功实现了间充质干细胞 (MSCs) 成骨分化过程中细胞力学变化的实时和长期 (超过 20 天) 监测。我们还使用微电极阵列芯片和显微镜观察进行电阻抗监测，研究 MSCs 在成骨分化过程中的细胞迁移和结节聚集行为。各种生化测定，包括碱性磷酸酶 (ALP)、骨桥蛋白表达和茜素红染色，用于验证 MSCs 的成骨分化。我们提出了细胞牵引力测量、阻抗测量和显微镜观察的组合，以提供细胞形态、细胞生物力学和电生理表型的多模式分析，可跟踪干细胞发育过程中的细胞动力学，并有助于深入了解成骨分化的机制。
