Study on in SITU enzyme - mediated preparation of biocompatible hydrogel composite for bone regeneration

Abstract

Injectable chitosan-based hydrogels have been widely studied towards biomedical applications because of their potential performance in drug/cell delivery and tissue regeneration. In this study, we introduce tetronic-grafted chitosan containing tyramine moieties which have been utilized for in situ enzyme-mediated hydrogel preparation. The hydrogel can be used to load biphasic calcium phosphate (BCP) nanoparticles forming injectable biocomposites. BCP nanoparticles (mixture of Hydroxyapatite and tricalcium phosphate) were prepared by precipitation method under ultrasonic irradiation using calcium chloride and tri-sodium phosphate. The BCP nanoparticles were characterized by using X-ray powder diffraction (XRD), scanning electron microscopy (SEM). The suspension of chitosan derivative and BCP nanoparticles rapidly formed hydrogel biocomposite within couple seconds in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H O ) at 2 2 physiological conditions. The compressive stress failure of the wet hydrogel was attended at 591  20 KPa with the composite 10wt% BCP loading. In vitro study using mesenchymal stem cells from bone marrow of rabbit showed that composite hydrogels were biocompatible and cells are well attached on hydrogel composite surfaces which are obtained by immunostaining. Mineralization of the hydrogel composite also has been studied in vitro. Keywords: Chitosan Horseradish peroxidase enzyme BCP nanoparticles Bone regeneration