| Calcium phosphate cements(CPCs)can be arbitrarily shaped according to the bone defect site without any prefabrication.Because of their advantages such as injectability,in-situ curing,favorable biocompatibility and osteoconductivity,CPCs have the potential of clinical applications in bone repairing.In this study,considering the deficiency of poor anti-washout ability,we developed a novel injectable CPC by introducing sodium polyacrylate(PAAS)and konjac glucomannan/guar gum(KGM/GG),konjac glucomannan/?-carrageenan(KGM/KC),which not only had a noticeable improvement in anti-washout property,but also avoided prolonging setting time and markedly reducing injectability.The physical and chemical properties(anti-washout property,injectanbility;rheological property,setting time,compressive strength,porosity,phase,microstructure;Zeta potential and protein adsorption)and in vitro cell behaviors of the modified anti-washout CPC were evaluated.This study reported an effectiveness of sodium polyacrylate(PAAS)in the enhancement of anti-washout ability of CPC.The results showed that PAAS significantly enhanced the anti-washout property and injectability of the cement paste.Meanwhile,PAAS hardly affected the precipitation of hydroxyapatite(HAp),setting time,and microstructure,but slightly reduced the compressive strength of CPC.The in vitro cell assessments demonstrated that all the samples were biocompatible and mouse bone mesenchymal stem cells(mBMSCs)well adhered,spread and proliferated on the samples.KGM and GG solutions with different concentrations and ratios were used as CPC liquid phase.The experimental results showed that KGM and GG could significantly improve the anti-washout property.The mass loss and injectability decreased with the increase of KGM and GG content.KGM/GG composite had more significant effect in improving the anti-washout ability of CPC by the synergistic effect of different polysaccharides.When the KGM/GG ratio was 5:5,CPC had the lowest mass loss.The injectability of CPC could be significantly improved with a low composite ratio.The CPC pastes added with KGM and GG exhibited a siginificant thickening effect.Both KGM and GG could reduce the final setting time of CPC,but the composite ratio of KGM/GG had little effect on the setting time,hydration products and fracture morphology of CPC.The compressive strength slightly decreased compared with the control group,but the compressive strength firstly increased and then decreased with the increase of KGM/GG composite ratio.Moreover,the CPC samples modified by KGM/GG allowed more protein adsorption,which was favorable for cell adhesion and proliferation,but the addition of KGM/GG had no remarkable effect on the osteogenic differentiation.KGM and KC solutions with different ratios were used as CPC liquid phase.The results showed that separate KGM and KC could significantly improve the anti-washout property of CPC,and KGM/KC composite had greater effect in improving the anti-washout ability of CPC by the synergistic effect.The viscosity of CPC pastes with KGM/KC was increased.When the ratio of KGM/KC was above 5:5,the CPC pastes exhibited a superior siginificant thickening effect.The injectability and setting time of CPC decreased when the ratio of KGM/KC was higher than 2:8.The ratio of KGM/KC had little effect on the phase and microstructure of hydration products of CPC and the hydrated products were lamellar and needle-like HAp.The compressive strength slightly decreased when compared with the control group.When the ratio of KGM/KC was 5:5,the compressive strength slightly increased.CPC with KGM/KC had enhanced surface electronegativity,but the electronegativity decreased with the increasing of ratio of KGM/KC.The introduction of KGM/KC decreased the absorption of BSA and increased that of LSZ,The in vitro cell assessments suggested that all the CPCs modified by KGM/KC had excellent cell compatibility,was good for the adhesion and proliferation of mBMSCs and had little effect on their differentiation. |
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