Photoencapsulation of chondrocytes in poly(ethylene oxide)-based semi-interpenetrating networks

A photopolymerizing hydrogel system provides an efficient method to encapsu late cells. The present work describes the in vitro analysis of bovine and ovine chondrocytes encapsulated in a poly(ethylene oxide)-dimethacrylate an d poly(ethylene glycol) semi-interpenetrating network using a photopolymeri zation process. One day after encapsulation, (3-[4,5-dimethylthiazol-2-yl]- 2,5-diphenyl-2H- tetrazolium bromide) (MTT) and Light microscopy showed cho ndrocyte survival and a dispersed cell population composed of ovoid and elo ngated cells. Biochemical analysis demonstrated proteoglycan and collagen c ontents that increased over 2 weeks of static incubation. Cell content of t he gels initially decreased and stabilized. Biomechanical analysis demonstr ated the presence of a functional extracellular matrix with equilibrium mod uli, dynamic stiffness, and streaming potentials that increased with time. These findings suggest the feasibility of photoencapsulation for tissue eng ineering and drug delivery purposes. (C) 2000 John Wiley & Sons, Inc. J Bio med Mater Res, 51, 164-171, 2000.