Chapter 39 - Designing Tunable Artificial Matrices for Stem Cell Culture

Abstract

This chapter focuses on progress in the design and characterization of artificial matrices that attempt to recapitulate microenvironmental cues for in vitro stem cell culture and differentiation. The physical structure, or microarchitecture, of an artificial matrix must provide appropriate physical signals, present or allow access to biochemical cues, and permit nutrient and waste exchange. Synthetic matrices should mimic some aspects of the natural properties of the collagen scaffold and adjacent proteins of the extracellular matrix (ECM), which constitutes a highly hydrated and fibrous network that supports cell attachment, migration, and other functions. One approach to mimicking the physical structure of the ECM is the creation of matrices of nanofibers prepared with electrospun polymers. Another approach to the design of artificial matrices for stem cells is to employ a hydrogel to mimic the physical properties of the natural ECM. Hydrogels emulate the high water content and porous nature of most natural soft tissues. Mechanical design parameters for artificial matrices include elasticity, compressibility, viscoelastic behavior, and tensile strength. Controlling the mechanical properties of a material at the cellular level can help elicit a desired cell response, and, in addition, the bulk mechanical properties of the matrix must be controlled such that the matrix is able to withstand loads that may be involved in downstream applications. The mechanical properties of synthetic and natural matrices are typically characterized by either atomic force microscopy or rheology.