Given the limited availability of fresh osteochondral allografts and uncertainty regarding performance of decellularized allografts, this study was undertaken as part of an effort to develop an osteochondral xenograft for articular cartilage repair. The purpose was to evaluate a simple antigen removal procedure based mainly on treatment with SDS and nucleases. Histology demonstrated a preservation of collagenous structure and removal of most nuclei. Immunohistochemistry revealed the apparent retention of α-Gal within osteocyte lacunae unless the tissue underwent an additional α-galactosidase processing step. Cytoplasmic protein was completely removed as shown by Western blot. Quantitatively, the antigen removal protocol was found to extract approximately 90% of DNA from cartilage and bone, and it extracted over 80% of glycosaminoglycan from cartilage. Collagen content was not affected. Mechanical testing of cartilage and bone were performed separately, in addition to testing the cartilage-bone interface, and the main effect of antigen removal was an increase in cartilage hydraulic permeability. In vivo immunogenicity was assessed by subcutaneous implantation into DBA/1 J mice, and the response was typical of a foreign body rather than immune reaction. Thus, an osteochondral xenograft produced as described has the potential for further development into a treatment for osteochondral lesions in the human knee. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2251-2260, 2018.

A negative photoresist approach towards physiologically responsive mechanically adaptive polymers that soften upon insertion into the body is reported. The framework relies on photoresists that can be processed into implants having complex shapes.

As a non-crosslinked osteochondral xenograft would be mechanically inferior to native cartilage and vulnerable to premature degradation, we seek a safe and effective method of xenograft stabilization. The purpose of this study was to evaluate the capacity for epigallocatechin gallate (EGCG) to stabilize a decellularized porcine osteochondral xenograft through collagen crosslinking. Our objectives were to assess the effects of EGCG on the degree of crosslinking, mechanical properties, collagenase resistance, cytotoxicity, and in vitro biocompatibility. EGCG is a green tea polyphenol that acts as a collagen crosslinker. Porcine osteochondral plugs were decellularized and then crosslinked by soaking in EGCG. The degree of crosslinking, cartilage compressive stiffness, cartilage-bone interface strength, coefficient of friction, and residual mass after collagenase exposure all increased with an increasing EGCG concentration. With the exception of the coefficient of friction, EGCG treatment could restore mechanical properties to levels equal to, or exceeding those, of native cartilage. EGCG treatment profoundly increased the enzymatic resistance, and 1% EGCG provided protection equivalent to 1% glutaraldehyde. EGCG up to 0.5 mM was essentially not cytotoxic to chondrocytes embedded in alginate, and autologous chondrocytes attached to decellularized, EGCG-fixed cartilage were all viable five days after seeding. Results demonstrate that EGCG has many beneficial effects on a decellularized osteochondral xenograft, and may be suitable for use in stabilizing such a graft prior to implantation for the repair of a defect.