Antibiotic-Loaded Porous Titanium Antibacterial Particle Coatings by High-Velocity Embedment into Silicone

Effective antimicrobial biomaterial surfaces are clinically beneficial as they can prevent infections caused by pathogens that are introduced during surgical procedures. Moreover, they can be advantageous for the long-term performance of medical devices. In the current study, we present an innovative procedure for the manufacture of biocompatible composite surfaces that provide controlled antibiotic release. We utilized titanium particles featuring a porous structure (pTi) as carriers and loaded these with crystalline ciprofloxacin (Cip). We then used these particles to modify the surface of polydimethylsiloxane (PDMS) substrates using cold spray deposition. The resulting surfaces (cipTi-PDMS) were characterized by scanning electron microscopy, energy dispersive X-ray analysis, 3D profilometry, Fourier transform infrared spectroscopy analysis, and water contact angle measurements. The cross-sections of the samples were also analyzed with optical microscopy to determine the embedding layer thickness. The areal density of drug-loaded Ti embedded on the substrate could be enhanced by increasing the cold spray gas temperature or decreasing the nozzle scanning speed. Our results show that the surface modification of PDMS using this method significantly increases the surface roughness and hydrophobicity of samples. The antibacterial efficacy of cipTi-PDMS surfaces against Staphylococcus aureus was demonstrated using a live/dead staining assay. An agar diffusion test also demonstrated that bacterial growth was effectively prevented for a period of 7 days. Moreover, no cytotoxicity was observed for cipTi-PDMS samples using MG-63 osteoblast-like cells after 7 days of incubation. Our results suggest that the composite surfaces can provide an effective defense against microbial colonization. We expect that this new approach will find applications in a range of polymer-based biomedical device applications.