Osteoblast differentiation and phenotype expressions on chitosan-coated Ti-6Al-4V

Chitosan (C), alginate-crosslinked chitosan (CA), and pectin-crosslinked chitosan (CP) were covalently bonded to Ti-6Al-4V surfaces and tested for their biocompatibility. Compared to the clinically treated Ti-6Al-4V surface (Ti64), C, CA, and CP, had higher contact angles and promoted higher cell proliferation, type I collagen deposition, and mineralization after two weeks (all p<0.05). Cells on C, CA, and CP expressed more alkaline phosphatase (ALP) activity compared to those on Ti64 (p<0.05). The swelling ratios and drug release efficacies of CA and CP were significantly higher and lower, respectively, than those of C (both p<0.05). Only cells on CA expressed ALP activity after three weeks of culture. Generally speaking, crosslinking with alginate and pectin changed surface wettability as well as the swelling and drug release properties of the chitosan coatings. Cells on the coatings had higher proliferation, type I collagen deposition, and degree of mineralization compared to those on Ti64.