Abstract:

BACKGROUND: Based on the consecutive adsorption of polyanions and polycations via electrostatic interactions, electrostatic self-assebly (ESA) technique has emerged as a versatile, inexpensive yet efficient technique to “build” biologically active surfaces for modification of biomaterial surface.
OBJECTIVE: Bioactive chitosan and heparin multilayers fixed on titanium surface via ESA technique are expected to be a new biologic surface to improve the cell biocompatibility of titanium.
METHODS: The film growth was initialized by depositing one layer of positively charged poly-L-lysine (PLL) on the NaOH-treated titanium substrate (negatively charged surface). Then, the film was formed by the alternate deposition of negatively charged heparin (Hep) and positively charged chitosan (Chi) via electrostatic interactions of polyelectrolytes, and terminated with an outermost layer of Chi. The chemical composition, surface topography as well as roughness were investigated by using diffuse reflectance Fourier transform infrared spectroscopy (DR-FTIR), scanning electric microscope (SEM) and atomic force microscope (AFM), respectively. We cultured osteoblasts on the surface of modified-titanium (Ti/Chi) and pure Ti (cpTi) respectively in vitro to observe morphologic change of cell attachment and spreading by SEM, and to estimate cell proliferation and differentiation by MTT test and ALP activity analysis.
RESULTS AND CONCLUSION: The analysis of DR-FTIR, SEM, and AFM confirmed that Chi-Hep multilayers formed gradually on the titanium surface. The film could improve the adherence, proliferation and differentiation of osteoblast. These results may provide a basis for the preparation of titanium surface modification for dental implants.