• atomic force microscopy
• elastic modulus
• mechanical properties
• mesenchymal stem cells
• poroelastic diffusion constant
• poroelasticity
• young’s modulus

Mesenchymal stem cells (MSCs) hold significant potential in the tissue engineering and regenerative medicine fields, as they combine accessibility and differentiation potential. The mechanical properties of MSCs can profoundly influence cell differentiation, and are of great interest for studies in the field of mechanobiology. However, they remain rather under-explored at present. Existing studies show relatively high variability, not only due to biological heterogeneities, but also to differences in methodologies used, which limits reliable cross-study comparisons. This work aims to fill this knowledge gap, by assessing the poroelastic diffusion constant and elastic modulus of MSCs. Atomic force microscopy (AFM) was used to determine these parameters, examining the effects of different batches, passages, and donor gender on data variability. MSCs from four donors (two male and two female) were cultured on a polystyrene (PS) membrane with a coating that promoted adhesion. Appropriate biological markers to confirm cell stemness were verified by immunofluorescence. AFM measurements were taken both over the cytoplasm and over the nucleus. Results revealed statistically significant batch-to-batch differences, an increasing trend in parameter values across passages, and surprising gender-related variations, with values of the female batches generally higher than values of the male ones. The variability we found across different parameters highlights the necessity for personalized, or at least gender-specific strategies in cell therapy applications of MSCs aimed at regenerative medicine.