Preparation And Characteristics Of Sr-doped Bioglass/Biphasic Tricalcium Phosphate Cements

Calcium phosphate cements (CPC) has been widely used to repair and replace the bone defects in clinic, which shows excellent biocompatibility, and can be molded to any desirable shape during operation with no heat release. However, the mechanical property of CPC is not enough, and its slow degradability in vivo and scarcity of porous structure for ingrowth of bone tissue and cells exactly limited its application. As a result the modification on CPC has a very important practical significance. Meanwhile, a mount of trace elements are also necessary in lesion of patient for new bone growth. Therefore, many studies are focusing on the preparation of a porous CPC with the appropriate compressive strength and high porosity which can be applied as the carrier of trace elements in the field of CPC research nowadays.Bioglass (BG) shows an excellent bioactivity and combination with bone tissues, such as fast degradation in vivo and capability of forming a bone-like structure on its surface. In this paper, Sr-doped bioglass was prepared by sol-gel and added into biphasic tricalcium phosphate cements (B-CPC), then the composite cements BG/B-CPC were soaked in deionized water to evaluate the degradable. Gillmore needles, XRD and SEM were used to characterize the phase composition and microstructure of the hydration products. The porosity and mechanical properties were tested.The results suggest the setting time of B-CPC was prolonged by the addition of Sr-dopped BG, with the increasing of BG content from 0 wt. % to 5 wt. %, the setting time reached (12.1±0.9) min to (33.4±3.7) min. Though the setting time was not significantly prolonged by the content of Sr in BG, it still can adjust the setting time slightly. The compressive strength (CS) and porosity of B-CPC were increased by the introduction of Sr-dopped BG. A porous composite cement with 3 wt. % of Sr-dopped BG containing 9 mol. % Sr was obtained after 7 day soaking in deionized water, and the compressive strength and porosity were (15.4±0.8) MPa and (51±3) % respectively. When the Sr-content was 15 mol. % in BG, some Sr2+ would release into water to form Sr-HA by replace Ca2+ in HA. The SEM photos suggest that the transformation fromα-TCP to HA was improved by addition of Sr-dopped BG.