Mesenchymal stem cells from the bone marrow are able to differentiate into chondrocytes (cartilage), adipocytes (fat) and osteoblasts (bone). Osteoblasts produce osteoid; which is furthermineralized to produce the bone matrix. Bone-tissue is mainly composed of bone matrix and osteoblasts. Chitosan and CHOS are known to increase the differentiation of mesenchymal stem cells to osteoblasts and to consequently facilitate the formation of bone-tissue [21,22]. The mineralization process and bone strength are dependent on Ca2+, which helps to support the structure. There is evidence that CHOS increase calcium-deposition in bone [22,144,145]. Jung et al. [144] found that CHOS could efficiently inhibit the formation of insoluble calcium-phosphate salts and consequently increase Ca2+ bioavailability and bone strength. They also found that CHOS (