Author ORCID Identifier

Defense Date


Document Type


Degree Name

Master of Science


Biomedical Engineering

First Advisor

Dr. Christopher Lemmon

Second Advisor

Dr. Rebecca Heise

Third Advisor

Dr. Christina Tang


Diseases involving fibrosis cause tens of thousands of deaths per year in the US alone. These diseases are characterized by a large amount of extracellular matrix, causing stiff abnormal tissues that may not function correctly. To take steps towards curing these diseases, a fundamental understanding of how cells interact with their substrate and how mechanical forces alter signaling pathways is vital. Studying the mechanobiology of cells and the interaction between a cell and its extracellular matrix can help explain the mechanisms behind stem cell differentiation, cell migration, and metastasis. Due to the correlation between force, extracellular matrix assembly, and substrate stiffness, it is vital to make in vitro models that more accurately simulate biological stiffness as well as measure the amount of force and extracellular matrix assembly. To accomplish this, blends of two types of poly(dimethylsiloxane) (PDMS) were made and the material properties of these polymer blends were characterized. A field of 5µm or 7µm microscopic pillars (referred to as posts) with a diameter of 2.2µm were fabricated from these blends. Each combination of PDMS blend and post height were calibrated and the stiffness was recorded. Additionally, polymer attachment experiments were run to ensure cells survived and had a normal phenotype on the different blends of PDMS when compared to pure PDMS. Finally, cells were placed onto a field of posts and their forces were calculated using the new stiffness found for each blend of post. Varying the PDMS material stiffness using blends allow posts to be much more physiologically relevant and help to create more accurate in vitro models while still allowing easy and accurate force measurement. More biologically relevant in vitro models can help us acquire more accurate results when testing new drugs or examining new signaling pathways.


© Thomas John Petet Jr.

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