In Situ Cell Encapsulation Into a Vascularized Hydrogel Matrix Using Stereolithography

Hydrogels are increasingly being used as cell encapsulation devices for both fundamental biology studies and cell transplantation therapies because of their structural similarity to the natural extracellular matrix. The successful use of a hydrogel in these biological applications relies greatly on the hydrogel permeability because it significantly affects the viability and function of cells. We hypothesized that incorporating interconnected micro-sized pores into a cell-encapsulating hydrogel would significantly improve the cell viability, depending on the spacing between micro-sized pores. In addition, increasing the diameter of the nano-sized pores in the hydrogel bulk was hypothesized to further elevate the fraction of viable cells. We found that the fraction of viable cells was significantly increased with mass fraction of methacylic alginate due to the increase of gel diameter in the nano-sized pore. The cell viability was further increased as the spacing between micro-sized pore introduced into a hydrogel with larger pore (~ 50nm) was decreased to 100 ƒÝm. In contrast, the spacing between micro-sized pores made minimal roles in the cell viability with use of a hydrogel presenting small pore diameter (~ 10 nm). Taken together, the results of this study demonstrated that the nano-sized pore diameter of hydrogel and spacing between micro-sized pores should be controlled in a balanced manner to maximize the viable cell population in the hydrogel network.