Substrate dependent control on the chiral orientation of mesenchymal stem cells: image-based quantitative profiling.

Stem cell chirality or left-right (LR) asymmetry is an essential attribute observed during tissue regeneration. Ability to instruct the LR orientation of cells by biophysical manipulation can be a promising approach for recapitulating their inherent function. Despite remarkable progress in tissue engineering, development of LR chirality in stem cells has been largely unexplored. Here, we demonstrate the role of substrate stiffness on LR asymmetry of cultured mesenchymal stem cells (MSC). We found that MSC acquired higher asymmetricity when cultured on stiffer PCL/Collagen matrix. To confirm cellular asymmetry, different parameters like aspect ratio, orientation angle and intensity of polarized proteins (Par) were investigated. The results show significant (p<0.01) difference in average orientation angle, cellular aspect ratio, the expression of actin and Par proteins in MSC cultured on matrices with different stiffness. Further, Gaussian SVM was applied to classify cells cultured on both the matrices with an accuracy of 96.2%. To best of our knowledge, present study for the first time interrelates and quantifies MSC asymmetricity with matrix properties using a simple 2D model.