Microbial biopolymers in articular cartilage tissue engineering

Articular cartilage tissue engineering offers promising alternative approaches using scaffolds, cells, and growth factors to current treatments to repair cartilage damage. Considering the existing treatment options for damaged cartilage that do not provide a permanent solution, it is important to mimic the extracellular matrix in the scaffolds to be developed and to provide an ideal microenvironment for chondrocytes. The scaffolds to be used for this purpose should be biocompatible, non-toxic, highly porous, and biodegradable and possess the desired mechanical properties. Microbial biopolymers have shown promising results in cartilage tissue engineering. These biopolymers can be classified as polysaccharides (bacterial cellulose, hyaluronic acid, alginate, dextran, pullulan, gellan gum, and xanthan gum), polyesters (polyhydroxyalkanoates), and polyamides (poly-gamma-glutamic acid and epsilon-poly-L-lysine). Although the functions of biopolymers as tissue scaffolds differ according to their properties, they are often used as a main support material; and their adjustable functionality by various modifications increases their pertinence. This review focuses on the use, modifications, and functionalization of microbial biopolymers in targeted scaffold designs for cartilage repair in articular cartilage tissue engineering.