Gentamicin-Loaded Bioactive Hydroxyapatite/Chitosan Composite Coating Electrodeposited on Titanium

Area of Science:

• Biomaterials Science
• Materials Engineering
• Nanotechnology

Background:

• Developing advanced coatings for biomedical applications is crucial for improving implant performance and preventing infections.
• Titanium-based implants are widely used, but their susceptibility to bacterial colonization necessitates effective antibacterial strategies.
• Natural polymers like chitosan (CS) and bioceramics like hydroxyapatite (HAP) offer biocompatibility and desirable surface properties.

Purpose of the Study:

• To synthesize and characterize a novel composite coating comprising gentamicin (Gent), chitosan (CS), and hydroxyapatite (HAP) on pure titanium.
• To evaluate the antibacterial efficacy of the developed composite coating against common bacterial strains.
• To assess the in vitro cytotoxicity of the composite coating for potential biomedical applications.

Main Methods:

• Electrophoretic deposition (EPD) was employed under optimized conditions (5 V, 12 min) to create HAP/CS and HAP/CS/Gent coatings in a single step.
• Advanced characterization techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) were utilized.
• Antibacterial activity was tested against *Staphylococcus aureus* and *Escherichia coli*, and cytotoxicity was evaluated using MTT assays on MRC-5 and L929 cell lines.

Main Results:

• The formation of HAP/CS and HAP/CS/Gent composite coatings on titanium surfaces was confirmed through various characterization methods, attributed to intermolecular hydrogen bonds.
• X-ray diffraction (XRD) analysis successfully identified hydroxyapatite (HAP) within the coatings via its characteristic diffraction peaks.
• The HAP/CS/Gent composite coating exhibited significant antibacterial activity against both *Staphylococcus aureus* and *Escherichia coli*.
• While the HAP/CS/Gent coating showed very mild cytotoxicity, the HAP/CS coating was classified as noncytotoxic.

Conclusions:

• The electrophoretic deposition technique is effective for creating multi-component HAP/CS/Gent composite coatings on titanium with favorable antibacterial properties.
• The developed composite coatings demonstrate high potential for bioapplication due to their effective antibacterial activity and acceptable biocompatibility.
• Further research into optimizing the gentamicin release profile and long-term in vivo performance is warranted for clinical translation.