Design and aligner-assisted fast fabrication of a microfluidic platform for quasi-3D cell studies on an elastic polymer

• Published in: Bioactive materials 2022-09, Vol.15, p.288-304
• Main Authors: He, Yingning, Yu, Yue, Yang, Yuqian, Gu, Yexin, Mao, Tianjiao, Shen, Yang, Liu, Qiong, Liu, Ruili, Ding, Jiandong
• Format: Article
• Language: English
• Subjects: Biomaterials; Cell stretching; Cell-material interaction; Microfluidic chip; Polymer
• ISSN: 2452-199X; 2452-199X
• DOI: 10.1016/j.bioactmat.2021.12.010

While most studies of mechanical stimulation of cells are focused on two-dimensional (2D) and three-dimensional (3D) systems, it is rare to study the effects of cyclic stretching on cells under a quasi-3D microenvironment as a linkage between 2D and 3D. Herein, we report a new method to prepare an elastic membrane with topographic microstructures and integrate the membrane into a microfluidic chip. The fabrication difficulty lay not only in the preparation of microstructures but also in the alignment and bonding of the patterned membrane to other layers. To resolve the problem, we designed and assembled a fast aligner that is cost-effective and convenient to operate. To enable quasi-3D microenvironment of cells, we fabricated polydimethylsiloxane (PDMS) microwell arrays (formed by micropillars of a few microns in diameter) with the microwell diameters close to the cell sizes. An appropriate plasma treatment was found to afford a coating-free approach to enable cell adhesion on PDMS. We examined three types of cells in 2D, quasi-3D, and 3D microenvironments; the cell adhesion results showed that quasi-3D cells behaved between 2D and 3D cells. We also constructed transgenic human mesenchymal stem cells (hMSCs); under cyclic stretching, the visualizable live hMSCs in microwells were found to orientate differently from in a 3D Matrigel matrix and migrate differently from on a 2D flat plate. This study not only provides valuable tools for microfabrication of a microfluidic device for cell studies, but also inspires further studies of the topological effects of biomaterials on cells. [Display omitted] •A microfluidic platform for quasi-3D cell studies was presented as a linkage between 2D and 3D cell-material research systems.•The fabrication difficulty was overcome by designing an effective aligner that can be easily assembled.•Cell behaviors can be enhanced with a proper quasi-3D biomaterial microenvironment.•A new transgenic cell line and systematic 3D approaches were developed to visualize and digitalize the quasi-3D cells.