Sustained release of bone morphogenetic protein-2 in interpenetrating composite hydrogels for promoting skull bone regeneration

Large craniofacial defect by trauma, congenital disease, or cancer resection raises serious difficulties for reconstructive surgeons. To date, bone tissue engineering applications have been developed to substitute these conventional medical approaches. A variety of biopolymer-based scaffold materials, especially hydrogels, have been used as effective growth factor (GF) carriers. Furthermore, bone morphogenetic protein-2 (BMP-2) is one of the most well known GF for promoting bone regeneration. Since, BMPs have a short half-life from about several minutes to hours in the body, a large amount of BMP is usually required to obtain a desired bone formation. However, direct administration of high dose of BMP-2 could cause various clinical side effects. Therefore, in this study, to achieve a sustained release of bioactive BMP-2 for skull bone regeneration, composite interpenetrating (IPN) hydrogel with polycation-based coacervate (Coa) and gelatin microparticle (GMP) as BMP-2 carriers were developed.