A Mechanochemical Microarray for Studying Combinatorial Effects on Embryonic Mesenchymal Cell Differentiation

Abstract

Embryonic mesenchymal cells mediate tooth formation during development as a result of physical and chemical interactions with their extracellular matrix (ECM) microenvironment. Engineering biomaterials relevant to tooth differentiation require a screening platform that incorporates both embryologically relevant properties relating to ECM stiffness as well as chemistry. Current ECM microarray technologies that screen for the effects of differences in substrate mechanical properties on cell differentiationare limited to ranges of high stiffness that are not relevant for the engineering of many cell types, such as stem cells and embryonic mesenchymal cell derivatives. Here, we describe the development of a novel polyacrylamide gel microarray platform and demonstrate its utility for the selection of odontogenic biomaterials. This microarray platform uses soft substrates (132, 558, and 1510 Pa) that closely mimic the embryonic microenvironment coatedwith the ECM proteins, Collagen VI and Tenascin (either alone or in combination), which have been shown to contribute to odontogenesis and permits combinatorial analysis of their effects on cell growth and differentiation. Using expression of the odontogenic transcription factor pax9 as a measure of tooth differentiation, we found that odontogenesis was the highest when mesenchymal cells isolated from embryonic mouse mandible (day 10) were cultured on 1510 Pa with Collagen VI (100 µ g/ml). This screening method is useful for selection and design of engineered materials for dental applications, as well as any challenge that involves engineering of tissues that depends on compliant ECM materials in combination with chemical cues from the microenvironment.