Compositional changes to brushite cements to improve mechanical and antibiotic-delivery properties

Brushite calcium phosphate cements (bCPCs) are promising synthetic bone substitutes due to their bioactivity, osteoconductivity, and controlled degradation. However, their clinical use is limited by poor handling, low mechanical strength, and insufficient antimicrobial capability. This study explores the incorporation of α-tricalcium phosphate (α-TCP) and silk fibroin (SF) to enhance bCPC performance and enable localized antibiotic delivery using tetracycline (TC). Adding α-TCP improved compressive strength (up to 2.65 MPa), while SF in liquid or fiber form reinforced the matrix. The inclusion of TC and SF extended setting times (4–7 min initial; 7–30 min final) and maintained injectability (up to 50 %). Drug release studies showed a 10 % burst in the first 24 h, with a sustained release of 77 % over 14 days. These multifunctional bCPCs offer injectable, resorbable, and antibacterial properties, making them suitable for non-load-bearing bone repair applications.