A two-step reaction to prepare a fast-hardening strontium-calcium phosphate scaffold in room temperature

Abstract

Objective To evaluate a fast-hardening strontium-calcium phosphate scaffold using a two-step reaction in room temperature. Methods The original powder phase consisted of tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA) and strontium hydrogen phosphate (DSPA). The liquid phase consisted of 20wt% citric acid and 12wt% polyvinylpyrrolidone K-30. Groups were designed as Sr-0, Sr-5, Sr-10, and Sr-20, according to the molar ratios of Sr/(Sr+Ca) being 0, 5%, 10%, and 20% in the powder phase, respectively. The ratio 0.5 mL/g in the liquid to solid phase was used for mixing. After the scaffold was prepared, its setting time, compression strength, phase composition and structural morphology, ions release and pH value of the substrates were analyzed. Results Addition of citric acid accelerated the setting reaction. Acceptable setting time was achieved by optimizing composition of the original powder and liquid phases. On the other hand, the compression strength, phase composition and structural morphology were not affected by addition of strontium. In addition, calcium and strontium ions were detected in the substrates, without any significant change in the pH value. Conclusion This two-step reaction can be used to prepare a fast hardening strontium-calcium phosphate scaffold in room temperature. Key words: Strontium; Calcium phosphates; Hydroxyapatites; Setting time