The study of self-regulating α-TCP based composite by micro/nano scaled silk fibroin and α-CSH on physicochemical and biological properties of bone cement

A novel self-hardening α-tricalcium phosphate (α-TCP) bone cement complexed with different content of α-calcium sulfate hemihydrate (α-CSH) and micrometer hydroxyapatite mineralized silk fibroin (HA-SF) using micro/SF as curing liquid has been investigated in this work, which was capable of tunable setting time, degradation, mechanical property and ability to anti-washout. After addition 0 ∼ 25% α-CSH to the α-TCP cement with SFFs as curing liquid, it shortened the setting time of the modified composite to 10 ∼ 30 min. Furthermore, the addition of SFFs improved the compressive strength of the composite from 5.41 MPa to 9.44 MPa. The composites with both Na2HPO4 and SFFs as curing liquid showed good anti-collapse performance. The weight loss ratio of bone cement was −0.18 ∼ 12.08% in 4 weeks when the content of α-CSH in α-TCP/α-CSH was between 0 ∼ 25 wt%. During the degradation of α-CSH, the amorphous α-TCP were deposited as hydroxyapatite to formed a plate-like products on the surface of composite. Compared to the composite with Na2HPO4 solution as the curing liquid, alkaline phosphatase (ALP) activity of the composites using SFFs as curing liquid were maintained at high levels on the 14th day especially when the Ca/P ratio was 1.7. This study provides a theoretical basis for the regeneration of bone defects guided by bone cement materials.