Work

Design of a biodegradable bone cement with enhanced mechanical and raloxifene-delivering properties

Year: 2026

Type: article

Abstract: Bone metastases associated with breast cancer weaken bone tissue and increase fracture risk, creating a need for injectable biomaterials that combine defect filling, fracture resistance and localized therapeutic activity. In this study, we developed a multifunctional magnesium-calcium phosphate cement (MgCPC) reinforced with electrospun polycaprolactone/polyethylene glycol (PCL/PEG) fibers loaded with raloxifene hydrochloride (RLX), a selective estrogen-receptor modulator with both anti-estrogenic activity in breast tissue and beneficial effects on bone. To our knowledge, this is the first study to incorporate RLX-loaded electrospun fibers into an injectable MgCPC matrix to simultaneously provide fiber-mediated toughening and delivery of biologically active RLX. Bead-free PCL/PEG fibers were produced by electrospinning, cryogenically milled and incorporated into the cement at 2 wt%. Fiber incorporation preserved cement injectability, with values of 91.3 ± 2.0% for MgCPC and 92.4 ± 2.0% for RLX-loaded fiber-reinforced MgCPC. The final setting time increased from 7.9 ± 0.4 to 11.2 ± 0.9 min but remained compatible with injectable handling. X-ray diffraction and Rietveld refinement showed similar crystalline phase proportions among the samples, indicating that fiber incorporation did not substantially alter the final phase composition. Although the addition of fibers reduced compressive strength from 32.6 ± 3.8 to 10.1 ± 1.1 MPa, it markedly enhanced fracture resistance. The work of fracture increased from 110.8 ± 22.4 J.m -2 for MgCPC to 416.1 ± 82.9 J·m -2 for the RLX-loaded composite, corresponding to an approximately 3.8-fold improvement. All tested cements were cytocompatible with human hFOB osteoblasts. In addition, cement extracts from the RLX-loaded cement significantly inhibited estrogen-responsive MCF-7 breast cancer cell proliferation, confirming the release of biologically active RLX. Fiber incorporation also slowed cement degradation in vivo , with 79.3% of the RLX-loaded composite remaining after 42 days compared with 51.6% for MgCPC. These findings demonstrate the potential of RLX-loaded fiber-reinforced MgCPC as an injectable multifunctional biomaterial combining preserved handling properties, enhanced fracture toughness, cytocompatibility, biological activity against estrogen-responsive MCF-7 cells and modulated degradation for future application in bone lesions associated with hormone-responsive breast cancer.

Source: Materials Today Communications

DOI: 10.1016/j.mtcomm.2026.115905