Date of Award


Document Type

Open Access Dissertation


Biomedical Engineering

First Advisor

Ehsan Jabbarzadeh


Human stem cells hold significant potential for the treatment of various diseases. However, their use as a therapy is hampered by the limited understanding of the mechanisms by which stem cells respond to environmental stimuli. Efforts to understand extracellular biophysical cues have demonstrated the critical roles of geometric and mechanical signals in determining the fate of stem cells. The goal of this study was to explore the interplay between cell polarity and matrix stiffness in stem cell lineage specification. We hypothesize that confining cells to asymmetric extracellular matrix (ECM) islands will impart polarity at a single-cell level and result in polarity signals that will interact with mechanical signals to define the lineage of stem cells. To test these hypotheses, we employed microcontact printing to create patterned symmetric and asymmetric hydrogel islands of soft and hard surface stiffness. Human mesenchymal stem cells (hMSCs) were confined to these islands at the single-cell level and cultured in differentiation media to differentiate along adipogenic or osteogenic routes. Our results established that cell polarity defines the lineage specification of hMSCs only on islands with low stiffness. Insight gained from this study provides a rational basis for designing stem cell cultures to enhance tissue engineering and regenerative medicine strategies.


© 2018, Maria Eugenia Piroli