Cell encapsulated and microenvironment modulating microbeads containing alginate hydrogel system for bone tissue engineering.

Functional tissue regeneration using synthetic biomaterials requires proliferation and heterotypic differentiation of stem/progenitor cells within a specialized heterogeneous (biophysical-biochemical) microenvironment. The current techniques have limitations to develop synthetic hydrogels, mimicking native extracellular matrix porosity along with heterogeneous microenvironmental cues of matrix mechanics, degradability, microstructure and cell-cell interactions. Here, we have developed a microenvironment modulating system to fabricate in situ porous hydrogel matrix with two or more distinct tailored microenvironmental niches within microbeads and the hydrogel matrix for multicellular tissue regeneration. Electrosprayed pectin-gelatin blended microbeads and crosslinked alginate hydrogel system help to tailor microenvironmental niches of encapsulated cells where two different cells are surrounded by a specific microenvironment. The effect of different microenvironmental parameters associated with the microbead/hydrogel matrix was evaluated using human umbilical-cord mesenchymal stem cells (hUCMSCs). The osteogenic differentiation of hUCMSCs in the hydrogel matrix was evaluated for bone tissue regeneration. This will be the first report on microenvironment modulating microbead-hydrogel system to encapsulate two/more types of cells in a hydrogel, where each cell is surrounded with distinct niches for heterogeneous tissue regeneration.