Synthesis and Characterization of Chitosan-Silicate Hydrogel as Resorbable Vehicle for Bonelike (R) Bone Graft

The use of bone grafts is required to restore skeletal integrity and enhance bone healing of large defects in several areas of regenerative medicine, such as: orthopedic and maxillofacial procedures. Some of these bone grafts can be resorbed in a time controlled way, in order to allow the correct process of natural re-construction of the involved bone tissue to occur. The Bonelike (R) graft is a bone substitute that mimics the inorganic composition of bone; this biomaterial was developed and characterized over the last decade. In a granular form, Bonelike (R) has proved its highly bioactive behavior in medical applications, such as; maxillofacial and orthopedics surgery. The clinical applications in maxillary bone defects indicated a good bone bonding between new formed bone and the Bonelike (R) granules. The purpose of this study was to develop a new injectable system for the application of Bonelike (R) using a resorbable vehicle which may be used in minimal invasive surgery. A new hydrogel derived from chitosan and gamma-glycidoxypropyltrimethoxysilane (GPTMS) was synthesized and characterized. The mixture derived from chitosan and GPTMS existed in sol state at room temperature and formed a hydrogel at 37 degrees C. The degradability of the hydrogel could be controlled by the concentration of chitosan and GPTMS, and the presence the presence of Bonelike (R) did not affect its degradability. The pH changes caused by the degradation of this hydrogel were small, so it is not expected to cause any deleterious effect in vivo conditions.