Date Approved

6-22-2021

Embargo Period

6-23-2021

Document Type

Thesis

Degree Name

M.S. Biomedical Engineering

Department

Biomedical Engineering

College

Henry M. Rowan College of Engineering

Advisor

Sebastián L. Vega, Ph.D.

Committee Member 1

Vincent Beachley, Ph.D.

Committee Member 2

Nichole Daringer, Ph.D.

Keywords

Cell Shape, Cell Stiffness, Mechanosensing, Mesenchymal Stem Cell

Subject(s)

Stem cells--Research

Disciplines

Biomedical Engineering and Bioengineering

Abstract

Cellular mechanosensing is the process of converting mechanical signals into biological responses. Stem cells are self-renewing cells with the potential to transform into specialized cell types - this differentiation process is influenced by cellular mechanosensing. Cells sense material stiffness, and stiffer environments result in increased cellular mechanosensing and preferential differentiation into bone-producing osteoblasts. Cell shape also plays an important role due to its influence on cytoskeletal contractility, and photopatterning can be used to study the effects of cell shape on cellular mechanosensing. Although the effects of material stiffness and cell shape have been studied, little is known about the joint effects of these factors on stem cell mechanosensing. Taken together, the goal of this research is to develop a biomaterial system to study the combinatorial effects of shape and stiffness on mesenchymal stem cell (MSC) mechanosensing. Hydrogels of three stiffness (5 kPa, 10 kPa, 20 kPa) were photopatterned with shapes (circle, square, octagon) that cause a range of contractile forces in cells. These shapes were made into patterns on a glass photomask, allowing hydrogels placed under the photomask to be photopatterned. Photopatterns were found to over 90% accurate. Highly angular shapes, such as the octagon, and increased stiffness were both seen to influence an increased nuclear localization of mechanosensing protein YAP, with stiffness having a greater influence than shape.

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