Cu-doped calcium phosphate supraparticles for bone tissue regeneration

Area of Science:

• Biomaterials Science
• Nanotechnology
• Orthopedic Materials

Background:

• Calcium phosphate (CaP) materials are promising bone replacements due to their bone-like composition.
• Preventing infection in bone grafts is critical, especially with rising antibiotic resistance.
• Controlled porosity in CaP materials is key for drug delivery and biodegradation, influencing material performance.

Purpose of the Study:

• To synthesize copper (Cu)-doped calcium phosphate (CaP) supraparticles for enhanced bone substitute properties.
• To evaluate the antibacterial efficacy and drug release profile of Cu-doped CaP supraparticles.
• To assess the biocompatibility of these novel bone substitute materials.

Main Methods:

• Calcium phosphate nanoparticles (NPs) were synthesized via a modified sol-gel process, yielding β-tricalcium phosphate (β-TCP) after calcination.
• Cu-doped CaP NPs (0.5-15.0 wt% Cu) were formed into supraparticles using spray drying.
• Copper release kinetics, antibacterial activity against Gram-positive and Gram-negative bacteria, and cytotoxicity with hMSC-TERT cells were evaluated.

Main Results:

• Cu-doped CaP supraparticles demonstrated sustained copper release over 14 days.
• Complete inhibition of *Bacillus subtilis*, *Staphylococcus aureus*, and *Escherichia coli* was achieved with 5.0 wt% Cu doping.
• High biocompatibility was observed with human telomerase-immortalized mesenchymal stromal cells (hMSC-TERT) at concentrations up to 0.01 mg mL^-1 over 72 hours.

Conclusions:

• Cu-doped CaP supraparticles effectively combine bone substitute potential with significant antibacterial properties.
• The sustained copper release and broad-spectrum antibacterial activity make these materials promising for infection-prone bone regeneration applications.
• The demonstrated biocompatibility supports their potential use in orthopedic applications without compromising cellular health.