Our group is interested in new technologies and strategies for osteochondral tissue regeneration. Some of the core tenets of our philosophy for tissue regeneration include the use of Ã¢ÂÂraw materialsÃ¢ÂÂ as building blocks, the engineering of continuous gradients, and leveraging osteochondral tissue engineering to enhance cartilage regeneration. The use of scaffolds built exclusively from microspheres provides a means for both raw materials and gradients to be employed in osteochondral tissue engineering. With the use of microspheres, we have shown that a single osteochondral biomaterial implant can be created with a continuous gradient in both material composition and growth factor release, with a seamless transition from one side to the other. We have further demonstrated the ability to create shape-specific scaffolds, and even fabricate the scaffolds in the presence of cells in a single step, by using dense phase CO2 to sinter the microspheres. A series of in vivo tests in both the knee and in the temporomandibular joint (TMJ, or jaw joint) have yielded promising results for the use of microsphere-based scaffolds. As an alternate strategy, we are pioneering the use of interpenetrating network (IPN) hydrogels to encapsulate cells for cartilage tissue engineering. We have shown that two different hydrogel networks can be combined in such a way to create an IPN hydrogel with mechanical integrity far superior to either of the original gels, with viable cells encapsulated. This IPN approach has been further enhanced with the incorporation of Ã¢ÂÂraw materialsÃ¢ÂÂ for cartilage. In addition, we have developed a gradient-based design for a biomaterial to treat tracheal stenosis (narrowed airway). Finally, we have introduced human umbilical cord WhartonÃ¢ÂÂs jelly cells (WJCs) to musculoskeletal tissue engineering, which has permeated a number of different applications in our group.