Effects of adding poloxamer, collagen, and citric acid on mechanical strength, injectability, shape stability, and biocompatibility of mechanochemically modified beta-tricalcium phosphate cement using ball milling

This study focuses on enhancing the mechanical properties and biocompatibility of calcium phosphate cement (CPC), a widely used bone replacement material. CPCs are limited by low mechanical strength and susceptibility to washout in body fluids. Four approaches were employed to improve CPC performance: 1. mechanochemical modification of CPC powder by ball milling to produce modified β-tricalcium phosphate (mβ-TCP) for better strength and injectability; 2. incorporation of poloxamer, a reverse thermosensitive gel, to enhance shape stability at body temperature; 3. addition of type I collagen to promote the cell viability and alkaline phosphatase (ALP) activity of osteoblast-like cells; 4. citric acid inclusion to restore compressive strength and injectability compromised by collagen. The resulting high-performance CPC demonstrated a compressive strength of 50.1 MPa, with significant improvements in injectability, shape stability, cell viability, and ALP activity of osteoblast-like cells.