Biocompatible and tunable elastic hyaluronic acid hydrogel for adult stem cell differentiation

POLY 534

Florian Rehfeldt, rehfeldt@sas.upenn.edu1, Shenshen Cai, scai@seas.upenn.edu2, and Dennis E. Discher1. (1) Chem & Biomol Eng; Cell & Mol Biology and Physics Grad Groups, University of Pennsylvania, 129 Towne Building, 220 South 33rd Street, Philadelphia, PA 19104-6315, (2) Department of Chemical & Biomolecular Engineering, University of Pennsylvania, 129 Towne Bldg, 220 S 33rd St, Philadelphia, PA 19104
Most of our cells reside in tissue of different stiffness, but it has only become clear over the last decade that substrate elasticity exerts a major influence on cell motility, contractility, and overall cell function. The mechanical properties of the matrix can even direct the differentiation of human adult stem cells as reported by our group recently (Engler et al. Cell 2006). Most of these studies have been conducted with synthetic and neutral polyacrylamide (PA) gel matrices, motivating more bio-relevant gel models. We have developed such a biocompatible hydrogel system of widely and finely tunable elasticity using hyaluronic acid (HA), which is ubiquitous in development and in particular adult tissues. The effective Young's modulus E of these negatively charged hydrogels measured by atomic force microscopy (AFM) can be finely tuned by variation of cross-linker and HA concentration yielding a stiffness of 0.1 kPa to 150 kPa. We will describe the influence of these unique gels on differentiation of human adult stem cells.