The cage implant system for determining in vivo biocompatibility of medical device materials

Biocompatibility of an implanted material, drug delivery system, or prosthetic is a dynamic two-way process that involves the time-dependent effects of the host on the material and the material on the host. Implantation of any synthetic material initiates a wound-healing mechanism that is characterized by the inflammatory response. We have developed a novel implant system that enables quantitative as well as qualitative evaluation of the inflammatory response to implanted materials. The cage implant system can be used to quantify the cellular and enzymatic components of inflammation and permits access to study cellular adhesion and interactions with candidate biomaterials. The basic methodology of the implant system is described. The effectiveness of the system is illustrated by comparing the results for three contrasting materials: polyethylene, poly(vinyl-chloride) containing a stabilizer that is cytotoxic, and poly(DL-lactide) containing hydrocortisone acetate.