Titania Nanotubes Modification with Cisplatin and Its Oxalate Analog Using Mercaptoorganosilanes as Bridging Ligands

Titanium implants can achieve higher osseointegration when covered with titania nanotubes (TNT). Given their specific morphology, titania nanotubes are excellent substrates for subsequent modifications. In addition to anti-inflammatory drugs, cytotoxic drugs can also be used. It can be achieved by simple physical adsorption of the drug molecules or by their covalent bonding to the surface using a bridging ligand such as (3-mercaptopropyl)trimethoxysilane (MPTMS), for example. The last method was used successfully before. The purpose of the study is to test different modifications of this method to analyze factors that will improve the studied methodology. The study compares two methods of TNTs modification with cisplatin (CDDP) and its oxalate analog (CDOP): drop casting (DC) and the application of MPTMS and its ethoxy analog, MPTES, as bridging ligands. Pluronic L-61 and alkaline Piranha solutions were used as surface activators for TNT. Both activators are effective. Analysis of the fabricated samples was executed using ATR, SEM, SEM/EDX, and AFM. Covalent bonding of Pt(II) complexes to the TNT arrays with a bridging ligand results in a homogeneous layer containing Pt(II) complexes. They release the surface within one hour (the mean values of the kobs for both complexes release in PBS and water are 9 · 10−3 s−1 and 4.8 · 10−3 s−1, respectively). Loading the Pt(II) complexes by drop casting yields layers with higher Pt (II) concentration (ca. 7.5%wt vs. ca. 3.2%wt for the second method and its variants) but lower homogeneity. No distinct general trends in the release rate on the TNT diameter were detected. The results show that modifying Ti6Al4V implants with titania nanotubes and further modifying them with platinum(II) complexes yields materials that can serve as carriers for anticancer platinum-based drugs.