Alginate encapsulation and hepatic differentiation of embryonic stem cells

Abstract

The emergence of cell based clinical technologies has been limited by the need for large cell masses (>10/sup 11/ cells). Embryonic stem cells are a promising solution to this cell source limitation because they are highly proliferative, renewable and pluripotent. Although many investigators have described techniques to effectively differentiate stem cells into a variety of mature cell lineages, these fall short in a number of ways including: 1) low yields of fully differentiated cells, 2) absence of large scale processing considerations and 3) ineffective downstream enrichment. Thus, a tissue culture microenvironment is required that may be modified to increase regulation of embryonic stem cell differentiation, and scaled to increase differentiated cell yield. Microencapsulation provides a vehicle for the discrete control of key cell culture parameters such as cell seeding density, rigidity, and substrate surface microarchitecture. In order to assess the feasibility of directing stem cell differentiation via microenvironment regulation, we have developed a murine embryonic stem cell (ES) alginate poly-L-lysine microencapsulation differentiation system. Our results indicate that the alginate microenvironment is biocompatible, is conductive to ES cell differentiation, and maintains differentiated cellular function. In addition, changes in alginate concentration and cell seeding density have proven effective in modulating differentiation as well as mature hepatic function.