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 C ₃S 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.