In situ assessment of cell viability within biodegradable polylactic acid polymer matrices.

Efforts to expand treatment options for articular cartilage repair have increasingly focussed on the implantation of cell polymer constructs. Primary cells cultured from perichondrium, a chondrogenic tissue, were found to survive in vitro within a biodegradable porous polylactic acid matrix. The novel application of an in situ fluorescent double-stain protocol to cell polymer constructs was supported by increased 3H-thymidine uptake and the ability of cell seeded polylactic acid to form first passage explant cultures. This in situ viability staining technique allowed for rapid determination of cell viability and, in conjunction with confocal microscopy, assessment of cellular distribution within a biodegradable scaffold. Advantages of using this method over histological and electron microscopic analysis include in situ observation, absence of distortion in scaffold architecture due to polymer dissolution and disruption during processing, and obtaining a viability assessment within 30 min. Potential applications of this protocol as a screening tool for laboratory engineered tissues and in the evaluation of cellular injury in natural tissues are discussed.