Anti-washout carboxymethyl chitosan modified tricalcium silicate bone cement: preparation, mechanical properties and in vitro bioactivity

Anti-washout CaF2 stabilized C3S (F-C3S) bone cement was prepared by adding water-soluble carboxymethyl chitosan (CMCS) to the hydration liquid. The setting time, compressive strength and in vitro bioactivity of the CMCS modified F-C3S (CMCS-C3S) pastes were evaluated. The results indicate that CMCS-C3S pastes could be stable in the shaking simulated body fluid (SBF) after immediately mixed. The addition of CMCS significantly enhances the cohesion of particles, at the same time restrains the penetration of liquid, and thus endows the anti-washout ability. The setting times of the pastes increase with the increase of CMCS concentrations in the hydration liquid. Besides, the compressive strengths of CMCS-C3S pastes after setting for 1-28 days are lower than that of the pure F-C3S paste, but the sufficient strengths would be suitable for the clinical applications. The crystalline apatite deposited on the paste surface is retarded from 1 to 2 days for the addition of CMCS, but the quantities of deposited apatite are same after soaking in SBF for 3 days. As the result that pure C3S paste has shorter setting times than pure F-C3S paste, CMCS modified pure C3S pastes would have better anti-washout ability. Our study provides a convenient way to use C3S bone cement with excellent anti-washout ability when the pastes are exposed to biological fluids. The novel anti-washout CMCS-C3S bone cement with suitable setting times, sufficient strengths and in vitro bioactivity would have good prospects for medical application.