The Role of a Nanogrooved Polydimethylsiloxane Substrate on Mesenchymal Stem Cells Adhesion, Self-Renewing, and Mechanical Properties

Stem cells have a variety of applications in biological, reconstructive medicine, and tissue engineering studies owing to their capacity to differentiate into specific cell lineages and their self-renewal ability. Among the factors affecting stem cells, biochemical agents such as growth and differentiation factors, along with environmental cues including physical and mechanical characteristics of the cell microenvironment, are of interest in this field. Several studies have evaluated the impact of physical factors such as mechanical forces, electric or magnetic fields, and light pulses on stem cell behavior. Also, cell culture substrates that can simulate extracellular matrix in natural conditions are considered the most critical environmental factors. Hence, in this study, we investigated the effects of a specially designed polydimethylsiloxane substrate with a surface pattern for cell contact guidance on various biological and biophysical characteristics of mesenchymal stem cells. Plasma treatment of the substrate under lateral tension from 50 to 200 seconds caused the increased wavelength of the formed wrinkle structures from 500±56 to 1052±182 nm, respectively, leading to variations of stiffness affecting the cell behaviors. Moreover, by increasing the available surface and hydrophilicity of the substrate, the cell attachment quality improved by more than 46% compared to the control. Finally, results of the mechanics of mesenchymal stem cells on these substrates obtained by bio-AFM showed an increase in the stiffness of cells despite a slight decrease in Young's modulus parameter of different substrates. These changes in the intracellular mechanics can eventually stimulate the more pivotal mechanobiological effects on stem cell fate.