The Fabrication And Cytocompatibility Of Chitosan Quaternary Ammonium Salt And PAA/PAH Coated NiTi Alloy

The infection rate of opening fracture and fracture internal fixation is higher.Infection cannot be completely eliminated in the part of bone fracture,then the follow-up treatment method also does not carry on,because infection is difficult to control and bacterial resistance.Coating nature antibacterial material on the surface of common medical metal implanting,it will not only achieve the longer antibacterial effect in the part of fracture,but also to avoid the bacteria resistance.Finally,infection is eliminated and the limb dysfunction is recovery.Chitosan quaternary ammonium salt(HACC)as chitosan derivative is an ideal modified material,not only possesses the anti-bacteria effect of quaternary ammonium salt,but also maintains the biocompatibility of chitosan.Objective: The aim of the study is to evaluate the osteoblast cell cytocompatibility of synthetized chitosan quaternary ammonium salt and poly(acrylic acid)(PAA)/poly(allylamine hydrochloride)(PAH)coated Ni Ti alloy.Methods: There are three parts in this study.Firstly,we used the chitosan,glycidyl trimethyl ammonium chloride and other materials to synthetize the chitosan quaternary ammonium salt,characterized by Fourier Transform Infrared Spectrometer(FTIR)and 1H Nuclear Magnetic Resonance(1H-NMR).Also,we tested the solubility and degree of substitution(DS).The chitosan quaternary ammonium salt micro-capsule is made by layer by layer assembled and marked by Rhodamine B.Secondly,surface activation and coated polymer were done on the Ni Ti alloy surface,the surface morphology and hydrophilicity were characterized by scanning electron microscope(SEM)and hydrophilic angle.Finally,the cytocompatibility of osteoblast was evaluated by CCK-8 and living-dead cell staining.Results: It is successful to synthetize the chitosan quaternary ammonium salt by the chitosan and glycidyl trimethyl ammonium chloride and other materials,and its solubility is 4.23 mg/ml,and the degree of substitution is 57.3%.It confirms that the micro-capsule contains the HACC by the Rhodamine B fluorescence.It is optimal to coat polymer(PAA/PAH)the surface of Ni Ti alloy and SEM shows porous the surface morphology.Also,the hydrophilicity was significant improvement.In 72 hours,cytocompatibility showed that micro-capsule solutions and two kinds of(PAA/PAH coated or not)Ni Ti alloy extracts solutions were no significant difference for the osteoblast.The osteoblasts adhered well,were healthy and no deformity when co-cultured with PAA/PAH coated Ni Ti alloy.Conclusion: The chitosan quaternary ammonium salt and the PAA/PAH coated Ni Ti alloy are not induced the bio-toxicity of osteoblast cell within 72 hours.