The Study Of Chitosan/Hydroxyapatite Bioeletret For Bone Substitute Materials

An electret has the property of charge storage, and the electret effect of biological tissues is a normal phenomenon. Many kinds of tissues and components in the body, such as blood vessels, bone, tendon, collagen, polysaccharides, enzymes, DNA and RNA show the electret effect. That electric stimulation can promote bone growth and repair has already been reported. However, it is not always convenient to apply an electric field in any treatment, so the use of electrets may be considered. Chitosan is the N-deacetylated derivative of chitin. It has been reported to be safe, hemostatic and osteoconductive, and to promote wound healing. Chitosan is an antimicrobial amino-polysaccharide that can be biodegraded by lysozyme. The Ph.D thesis is focused on the study of chitosan/ hydroxyapatite bioeletret and the effect of its electret property as a basis for the promotion of bone restoration.This research is composed of the following three parts.Part one: preparation and properties of chitosan/ hydroxyapatite bioeletret. In this part, the methods of preparing bioeletret were explored and optimized. The influences of polarizing voltage, polarizing time, and polarizing temperature to the electret property was studied. And the optimal technical route was concluded.Part tow: biomimetic mineralization and degradation of chitosan bioeletret in vitro. In this part, three different biomimetic methods were used for the mineralization of chitosan bioeletret. And the optimal method was concluded.At the third part of the thesis, in vitro experiments were designed and carried out to evaluate the biological reaction of the bioeletret. The BMSCs and OB cells were culture on chitosan/ hydroxyapatite bioeletret surfaces in vitro. Cell attachment, spreading, cell proliferation and differentiation were evaluated.Based on these findings, we could obtain chitosan/ hydroxyapatite bioeletret by using polarization and biomimetic mineralization. The novel bioeletret is biodegradable and has an excellent cytocompatibility for the growth of osteoblasts. Chitosan/ hydroxyapatite bioelectret may have value as a biomaterial in hard tissue restoration applications.