Development of bioactive and biodegradable chitosan-based injectable systems containing bioactive glass nanoparticles.

There is increasing interest in the development of new tissue engineering strategies to deliver cells and bioactive agents encapsulated in a biodegradable matrix through minimally invasive procedures. The present work proposes to combine chitosan-beta-glycerophosphate salt formulations with bioactive glass nanoparticles in order to conceive novel injectable thermo-responsive hydrogels for orthopaedic reconstructive and regenerative medicine applications. The initial rheological properties and the gelation points of the developed organic-inorganic in situ thermosetting systems were revealed to be adequate for intracorporal injection. In vitro bioactivity tests, using incubation protocols in simulated body fluid (SBF), allowed the observation of bone-like apatite formation in the hydrogel formulations containing bioactive nanoparticles. The density of the apatite formed increased with increasing bioactive glass content and soaking time in SBF. These results indicate that the stimuli-responsive hydrogels could potentially be used as temporary injectable scaffolds in bone tissue engineering applications.