Design and preparation of biocompatible zwitterionic hydroxyapatite

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Nanotechnology

Background:

• Hydroxyapatite (HA) is a key biomaterial in bone regeneration.
• Bacterial adhesion to HA implants leads to infections, necessitating new strategies.
• Developing HA with inherent antibacterial properties is crucial for clinical success.

Purpose of the Study:

• To design and prepare zwitterionic nanocrystalline hydroxyapatite (HA).
• To evaluate its ability to inhibit bacterial adhesion while supporting osteoblast colonization.
• To confirm the feasibility of this functionalization across various HA forms.

Main Methods:

• Surface functionalization of HA powders using 3-aminopropyltriethoxysilane (APTES) and carboxyethylsilanetriol sodium salt (CES).
• Characterization using elemental analysis, FTIR, solid-state NMR (²⁹Si, ³¹P, ¹³C), and ζ-potential measurements.
• Fabrication of 3D macroporous HA scaffolds via rapid prototyping and subsequent zwitterionization.

Main Results:

• Successful grafting of amine and carboxylate precursors confirmed zwitterionic HA (-NH₃⁺/-COO^- pairs).
• Zwitterionized HA demonstrated significant inhibition of *E. coli* adhesion.
• In vitro studies showed maintained biocompatibility with human HOS cells.
• The zwitterionization process was effective on various HA physical forms (particles, scaffolds, etc.).

Conclusions:

• Zwitterionic functionalization provides HA with effective bacterial anti-adhesive properties.
• This approach is versatile and applicable to diverse HA forms and applications.
• The method enhances implant safety by reducing infection rates without compromising biocompatibility, showing promise for dental and surgical fields.