Peptides of human body fluids as sensors of corrosion of titanium to titanium dioxide. SERS application

Abstract

Technical titanium (Ti) and its alloys are the most commonly used biomaterials. Therefore, it is important to know how the corrosion of a metal device implanted in the human body causes clinically significant problems and it is necessary to develop an in vivo method to examine the condition of the implant. Raman spectroscopy offers the possibility of inserting a Raman probe into the vicinity of the implant to determine the surface condition of the implant and the content of titanium dioxide (TiO2) in the surrounding area. For this purpose, trace elements in human body fluids; e. g., peptides, can be used. For the above reasons, in this work the surfaces of Ti plate and TiO2 (anatase and rutile) nanostructures (TiO2NPs) were characterized using ultraviolet–visible (UV–Vis), Fourier-transform infrared (FT-IR), Raman, and X-ray photoelectron (XPS) spectroscopies as well as scanning electron microscope with energy dispersive X-ray (SEM-EDS) and X-ray powder diffraction (XRD). These metal surfaces were used as highly sensitive, uniform, and reproducible sensors of the natural ligand (bombesin, BN) of some types of metabotropic seven transmembrane G protein-coupled superfamily receptors (GPCRs), which are over-express on the surface of many malignant tumors and are present in human body fluids. Surface-enhanced Raman scattering (SERS) was used to monitor the geometry of adsorbate, to separate, enrich, and detect a variety of BN fragments in a physiological environment and to determine the type of surface (Ti vs TiO2). Our work extends the use of SERS to monitor the implant surface and the presence of titanium oxide in the surrounding environment as well as the use of Ti/TiO2NPs as potential receptor-positive cancer markers or the use of peptides to inhibit the photocatalitic properties of anatase TiO2NPs.