3D-printed lithium-incorporated strontium calcium phosphate scaffolds as bone regenerative materials: Fabrication,...

Strontium calcium phosphate (SrCa₂(PO₄)_2, SCP) bioceramic scaffolds represent promising bone regenerative biomaterials; however, their clinical potential is limited by insufficient mechanical strength and osteostimulatory capacity. To address these limitations, this study fabricated lithium-incorporated SCP (Li-SCP) scaffolds with varying Li⁺ concentrations (0-15 mol%) via 3D printing technology. The incorporation of Li⁺ significantly promoted sintering densification, thereby reducing porosity and enhancing compressive strength. In vitro evaluations demonstrated that the degradation rates could be tailored by adjusting the Li⁺ content. Furthermore, the Li-SCP scaffolds supported the adhesion and proliferation of mesenchymal stem cells. Specifically, the sustained release of Li⁺ notably enhanced alkaline phosphatase (ALP) secretion, accelerated extracellular matrix calcification, and stimulated the expression of osteogenesis-related genes. Scaffolds incorporating 5.0 and 7.5 mol% Li⁺ exhibited an optimal balance between mechanical integrity and osteogenic activity. These findings suggest that 3D-printed Li-SCP scaffolds are viable candidates for further preclinical investigation in bone tissue engineering.