Porous composites for adhering artificial cartilage to bone

Artificial cartilage can be grown from cultured chondrocytes, but adhering this tissue to bone presents a challenge. Porous polymer/bioactive glass composites are candidate materials for engineering the artificial cartilage/bone interface and possibly other soft-to-hard tissue (ligament/bone, tendon/bone) interfaces. A phase separation technique was used to make porous polymer/bioactive glass composites. The composites (thickness: 200-500 μm) have asymmetric structures with dense top layers and porous structures beneath. The porous structures consist of large pores (>100 μm) in a network of smaller (<10 μm) interconnected pores. The dense layers were removed and large pores exposed by abrasion or salt leaching from the casting surface. The tissue bonding abilities of the composites were studied in vitro in simulated body fluid (SBF) and in rabbit chondrocyte culture. Culture studies revealed that composite surfaces were suitable for attachment, spreading and proliferation of chondrocytes. The growth of hydroxycarbonate apatite (HCA) inside and on the composites after soaking in the SBF for two weeks demonstrates their potential for integration with bone. The results indicate the potential for the composites to facilitate growth and attachment of artificial cartilage to bone.