Multifunctional Polymeric Bioactive Coatings on Ti Implants through the Drug Delivery Approach: In Vitro Corrosion Resistance, Biocompatibility, and Antibacterial Characteristics

In the current study, we developed a controlled drug delivery system using a polymeric matrix composed of biopolymer poly(vinylidene fluoride) (PVDF) and ciprofloxacin (CPF)-loaded titanium (Ti) nanotubes (TNTs) on Ti substrates for biomedical applications. The TNT arrays over the Ti surface were obtained through an anodization route. The PVDF coatings were dip-coated on TNT-Ti loaded with CPF. The chemical, microstructure, and surface properties of the TNTs and coated surfaces were characterized using FTIR, XRD, transmission electron microscopy (TEM), scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS), and surface hydrophilicity analyses. The performance of the implant surfaces was evaluated through in vitro corrosion studies in simulated body fluid (SBF), biocompatibility with MG63 cells, and antibacterial properties. The results revealed that the PVDF/0.1CPF coatings exhibited sustained release of CPF from the polymer matrix at a linear rate and releasing profile for 168 h. PVDF/0.1CPF coating showed decreased corrosion current density (4.457 × 10^-9 A/cm²) by 2 orders of magnitude than that of the Ti substrate, indicating enhanced corrosion protection in the SBF. PVDF/0.1CPF coating showed an antibacterial efficacy of 84.44% against Escherichia coli and 88.33% against Bacillus licheniformis after 24 h. The biocompatibility result showed that after 5 days of culturing, the PVDF/0.1CPF was pointedly higher than that of the pure PVDF and uncoated specimens. Additionally, after 7 days of culture, the quantity of cells on the PVDF/0.1CPF coating continued to increase significantly, whereas the bare specimens and pristine PVDF showed a lower rate of proliferation. The proposed biocompatible polymeric coatings hold synergic antibacterial and corrosion-resistant potential for biomedical applications.