Preparation of anti-decay self-setting pastes of hydroxyapatite/collagen utilizing (3-glycidoxypropyl)trimethoxysilane

This article describes preparation of anti-decay self-setting pastes of hydroxyapatite/collagen (HAp/Col) utilizing (3-glycidoxypropyl)trimethoxysilane (GPTMS). The powder portion of the paste was ball-milled HAp/Col synthesized by the simultaneous titration method, and the liquid portion was GPTMS aqueous solution at a concentration of 0.1, 1.0 or 10 % in volume. The HAp/Col-GPTMS pastes were prepared by mixing the powder and liquid portions at powder/liquid (P/L) ratios ranging from 0.20 to 2.00 (g/cm3). The pastes with P/L ratios from 0.33 to 1.50 showed good handling properties, and their viscosities depended greatly on the P/L ratio. The lowest washout ratio was observed at a P/L ratio of 1.00 independent of the GPTMS concentration. Although cytocompatibilty tests showed that inhibition of cell proliferation depended on the elution amounts of GPTMS from the pastes, an animal test using porcine tibia demonstrated no harmful systemic or local symptoms, because the GPTMS concentration maintained acceptable levels for living tissues through dispersion with body fluid. The animal test also revealed that the paste was completely resorbed and substituted with newly formed bone after 12 weeks implantation. It was concluded based on these results that HAp/Col-GPTMS pastes are promising candidates for use as bioresorbable injectable pastes