Engineering Gradient Hydrogels to Determine Optimal Elasticity for Cell Adhesion

Engineering gradient hydrogels to determine optimal elasticity for cell adhesion

Joshua C. Morgan, Yong Yang, and Allison Bruce

Department of Chemical Engineering, Benjamin M. Statler College of Engineering and Mineral Resources, West Virginia University, Morgantown, WV 26506

            Hydrogels are water-swollen polymers with novel physical and chemical properties that make them excellent scaffolds for studying cellular differentiation, migration, and adhesion.  Cell adhesion is a function of many physical properties, specifically elasticity, of living tissues or synthetic scaffolding systems.  It has been determined that the elastic modulus of hydrogels can be altered by varying the polymer to water ratio in their composition.  The first part of this study involved culturing HeLa cells on hydrogels of variable elasticity and observing cellular adhesion.  It was observed that cell density was greater on stiffer hydrogels with lower water content.  Afterwards, a microfluidic gradient generator was designed to produce a hydrogel of gradient elasticity, corresponding to a gradient of polymer concentration.  This gradient generator functions with two streams, water and polymer, that are injected into and flow longitudinally through the gradient generator.   Dividers within the gradient generator provide restricted diffusion, producing a gradient hydrogel at the outlet.  This hydrogel will be used to study cell migration in attempt to find the optimal elasticity for adhesion of normal cells as compared to that of cancerous cells.  Ultimately, this gradient generator will be employed as a separation device to isolate cancerous cells from an overall cell population so that they may be studied further.