A biodegradable composite scaffold for cell transplantation

Cell transplantation is rapidly becoming a therapeutic option to treat disease and injury. However, standard techniques for cell seeding on non-woven polymer meshes or within gels may not be suitable for immediate implantation or surgical manipulations of freshly isolated cells. Therefore, a biodegradable composite system was developed as a way to rapidly entrap cells within a support of predefined shape to potentially facilitate cell delivery into a target site (e.g. meniscal tears in the avascular zone). The composite construct consisted of freshly isolated cells, in this case pig chondrocytes, entrapped in a fibrin gel phase and dispersed throughout the void volume of a polyglycolic acid (PGA) non-woven mesh. Composites were cultured for up to 4 weeks. In vitro degradation of fibrin gel was evaluated via gel-entrapped urokinase. At 28 days in culture, glycosaminoglycan (GAG) content per cell in the composite scaffolds was 2.6 times that of the PGA-only cell construct group and 88% that of native pig cartilage. Total collagen content per cell in the composite scaffolds was not significantly different from the PGA-only cell construct group (P > 0.02) and represented 40% of the value determined for native cartilage. Varying the concentration of entrapped urokinase could effect controlled degradation of fibrin gel.