Carboxymethyl cellulose-stabilized calcium phosphate particles for injectable hydrogel-based bone tissue engineering†

Calcium phosphate (CaP) is a widely used biocompatible and bioactive material for bone tissue engineering due to its similarity to the mineral component of natural bone. Amorphous calcium phosphate is a highly reactive form of CaP that can undergo a phase transformation into a more stable crystalline phase, making it an attractive candidate for bone regeneration applications. However, amorphous CaP is highly unstable in aqueous solutions, which limits its use in practical applications. To overcome this limitation, this research aimed to employ carboxymethyl cellulose (CMC), a water-soluble biopolymer, as a stabilizer for CaP particles. CMC can form a protective layer around CaP particles, enhancing their stability and dispersion in aqueous solutions. An in situ wet chemical process was used to prepare CaP/CMC particles. A concentration of 500 mg L⁻¹ of CMC was found to effectively stabilize the synthesized CaP particles, resulting in good dispersity. These particles were then integrated into an injectable hydrogel made of methacrylated hyaluronic acid (MeHA) to create a promising material for bone regeneration applications. The use of CaP and CMC in combination with an injectable MeHA hydrogel provides a promising approach to develop a stable, injectable material for bone regeneration.