Additionally, PHA family members may be blended with each other. Scaffolds made from PHBHHx and PHB at a ratio of 1:1 have a higher surface free energy and are more ffective for chondrocyte adhesion than scaffolds made of PHBHHx alone (19). In another study, adipose-derived mesenchymal stem cells inoculated on PHB/PHBHHxscaffolds and implanted into animals were found to generate cartilage-like tissues 14 days after implantation