Engineering bone repair with K21-Infused brushite cement: In-vitro and in-vivo insights

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Nanotechnology

Background:

• Calcium phosphate biomaterials face challenges in antibacterial properties and mechanical strength for bone regeneration.
• Brushite cements are biodegradable and osteoconductive but lack antimicrobial effects.
• Quaternary ammonium compounds (QACs), like K21, offer potent antibacterial activity and promote tissue healing.

Purpose of the Study:

• To develop and evaluate a novel K21-doped brushite cement with improved antibacterial and anti-inflammatory characteristics.
• To assess the efficacy of K21-doped brushite cement in promoting bone regeneration and reducing inflammation.
• To determine the optimal concentration of K21 for balancing safety and therapeutic benefits.

Main Methods:

• Synthesized brushite granules and loaded them with 0.5% and 1% K21.
• Characterized materials using X-ray diffraction, Raman spectroscopy, and porosity analysis.
• Evaluated K21 release, in vitro antimicrobial efficacy against dual-species biofilms, cytocompatibility, and anti-inflammatory activity. Assessed bone regeneration and inflammation in rabbit mandibular defects in vivo.

Main Results:

• K21 incorporation exhibited pH-sensitive release, with higher concentrations yielding greater drug release.
• Both 0.5% and 1% K21 cements demonstrated significant antimicrobial effects, with 1% showing stronger bacteriostatic activity.
• The 0.5% K21-doped cement promoted ~95% new bone formation and reduced inflammation in vivo, while the 1% formulation increased inflammation.

Conclusions:

• K21-doped brushite cements offer combined antibacterial, anti-inflammatory, and bone regenerative benefits.
• The 0.5% K21 formulation demonstrated an optimal balance of safety and efficacy for craniofacial applications.
• This dual-action material holds promise for improving outcomes in repairing dental and maxillofacial defects by mitigating infection and inflammation.