Kefiran, an innovative biopolymer for cartilage tissue engineering

Polysaccharide-based scaffolds have been greatly explored for tissue engineering and regenerative medicine applications due to their biocompatibility and biodegradability. Recently, there has been a growing interest in kefiran, a water-soluble heteropolysaccharide produced by the natural microbiota of kefir grains which are used to produce kefir, a centuries-old probiotic fermented milk beverage known for its nutritional and health-promoting properties. When compared with other polysaccharides, kefiran has several additional advantages that include antimicrobial, anti-inflammatory, antioxidant and immunomodulatory activity, among others. The many attractive characteristics of kefiran, together with its recognised safe status, has led to extensive research on different areas of application, mostly in the food industry. However, recent research has also shown interesting physicochemical and biological properties for regenerative medicine and tissue engineering. Kefiran has shown great potential for viscosupplementation in osteoarthritis treatment and proper kefiran-based scaffolds have been developed by freeze gelation, showing stability, elastic behaviour and high porosity, with the ability of controlled drug release and biocompatibility. Kefiran may be used to treat/prevent bone and cartilage disease or defects and also for wound healing, representing a promising economical and environmentally improved alternative to hyaluronic acid, the gold standard viscosupplement to restore the joint synovial fluid viscoelastic properties of osteoarthritis patients. Moreover, the unique microstructure of kefiran-based scaffolds makes this biopolymer remarkable among common materials due to its outstanding properties for tissue engineering scaffolding. Kefiran cryogels could also represent potential drug delivery/release systems that tend to better control the disease at minimum doses, avoiding overdose and lowering antagonistic side effects. Nonetheless, further research is needed not only to better understand its function over cell proliferation and differentiation but also to improve scaffold design techniques to achieve clinical applications. Hence, kefiran represents a promising and appealing biomaterial for cartilage tissue engineering and regenerative medicine applications.

S. Correia is supported by the Portuguese Foundation for Science and Technology (FCT) through the R&D Project KOAT - Kefiran exopolysaccharide: Promising biopolymer for use in regenerative medicine and tissue engineering, with reference PTDC/BTMMAT/29760/2017 (POCI-01-0145-FEDER-029760), financed by FCT and co-financed by European Regional Development Fund (FEDER) and Operational Programme for Competitiveness and Internationalisation (POCI). H. Radhouani is supported by the FCT (CEECIND/00111/2017) and J. M. Oliveira would like to thank the FCT for funding provided under the program Investigador FCT 2015 (IF/01285/2015).