Micromechanical Compatibility Between Cells and Scaffolds Directs Phenotypic Transition of Stem Cells

Published

January 28, 2022

Author(s)

Yang Song, Jiaoyue Long, Jeremiah Woodcock, Joy Dunkers, Hung Chun Lin, Douglas M. Fox, Xiaoling Liao, Yonggang Lv, Li Yang, Martin Chiang

Abstract

This study experimentally substantiates the micromechanical compatibility between cell and substrate is essential for cells to achieve energetically favorable mechanotransduction that directs phenotypic transitions. The argument for this compatibility is based on a thermodynamic model that suggests the response of cells to their substrate mechanical environment is a consequence of the interchange between forms of energy governing the cell-substrate interaction. Experimental validation for the model has been carried out by investigating the osteogenic differentiation of dental follicle stem cells (DFSCs) seeded on electrospun fibrous scaffolds. Electrospinning of blends containing polycaprolactone (PCL) and silk fibroin (SF) with varying composition of cellulose nanocrystals (CNC) resulted in three-dimensional (3D) fibrous scaffolds with bimodal distribution of fiber diameter, which provides both macroscopically stiff and microscopically compliant scaffolds for cells without affecting the surface chemical functionality of scaffolds. Atomic force microscopy (AFM) with a colloidal probe and single-cell force spectroscopy were used to characterize cell stiffness and scaffold stiffness on the cellular level, as well as cell-scaffold adhesive interaction (chemical functionality). This study has successfully varied scaffold mechanical properties without affecting their surface chemistry. In vitro tests indicate that the micromechanical compatibility between cells and scaffolds has been significantly correlated with mechanosensitive gene expression markers and osteogenic differentiation markers of DFSCs. The agreement between experimental observations and the thermodynamic model affirms that the cellular response to the mechanical environment, though biological in nature, follows the laws of the energy interchange to achieve its self-regulating behavior. More importantly, this study provides systematic evidence, through extensive and rigorous experimental studies, for the first time that rationalizes micromechanical compatibility is indeed important to the efficacy of regenerative medicine.

Citation

ACS Applied Materials and Interfaces

Pub Type

Journals

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Keywords

Phenotype Transition, Scaffold Stiffness, Electrospinning, Cellulose Nanocrystals, Single-cell Force Spectroscopy

Citation

Song, Y. , Long, J. , Woodcock, J. , Dunkers, J. , Lin, H. , Fox, D. , Liao, X. , Lv, Y. , Yang, L. and Chiang, M. (2022), Micromechanical Compatibility Between Cells and Scaffolds Directs Phenotypic Transition of Stem Cells, ACS Applied Materials and Interfaces, [online], https://doi.org/10.1021/acsami.1c17504 (Accessed April 26, 2024)