It is the designation of molecules consisting of random co-polymers of 3-hydroxybutyrate and 3-hydroxyhexanoate [2]. A co-polyester consisting of 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HHx) can be synthesized by Aeromonas hydrophila strain 4AK4 with long-chain fatty acids as the carbon source [3, 4]. PHBHHx has good physical, chemical and mechanical properties [5-7], making it potentially useful for a wide range of biomaterials applications. In addition, it has also shown better biocompatibility with different cell types, such as smooth-muscle cells [8], fibroblasts [9], chondrocytes
[10], osteoblasts [2] and bone marrow cells [11]. PHBHHX plays a significant role in the field of biomedical materials and has become a popular research field in recent years. In this paper, we will review this new material in biomedical tissue engineering research.