We have recently developed a new technology called tissue-initiated photopolymerization, which permits direct covalent integration of a polymer into collagen, that has been shown to mechanically stabilize the hydrogel-cartilage interaction. Furthermore, the technique we have developed, allows in situ hydrogel formation to occur without exogenous photoinitiator, improving biocompatibility. Patent applications covering this technology have been filed. There are several envisoned applications of this technology, and the objective of this program is to develop the first application, to provide a method for annealing of grafted cartilage to the surrounding host articular cartilage. It is anticipated that this will provide a stable implantation of grafts into the articular defect site, and that this will substantially increase long term performance of the implanted material. The overall hypothesis for this program is that articular cartilage can be successfully integrated into the surrounding tissue to repair focal articular defects. The work in the Phase I project was to demonstrate feasibility of the approach, with the goals to achieve adhesion >2 times greater (160 kPa) than that achieved previously, and to not extend cell death beyond what would be expected by cutting cartilage (100-200 um). The adhesion strength achieved was 543 kPa, and cell death was not extended beyond 113 um. We therefore achieved the goals in the Phase I project.
The aims of the Phase II project is to optimize the device for articular cartilage, demonstrate effectiveness in a goat model of osteochondral repair, and assess biocompatibility. The successful outcome of this project will allow for submission to the FDA for product clearance (510k) or initiation of a clinical trial.