Avantage data system software

An X-ray photoelectron spectroscopic (XPS) analysis was performed using a Thermo Scientific K-alpha X-ray photoelectron spectrometer (Thermo Fisher Scientific, Waltham, MA, USA), equipped with a monochromatic X-ray source (Al Kα, hν = 1486.6 eV) operating at 150 W. The spectrometer energy scale was calibrated using the Au 4f7/2 photoelectron peak at a binding energy (BE) of 83.98 eV. During analysis, the samples were flooded with low-energy electrons to counteract any surface charging that may occur. The hydrocarbon component of the C 1s peak (BE = 284.8 eV) was used as a reference for charge correction. Photoelectrons emitted at an angle of 90° to the surface from an area of 700 × 300 μm² were analysed with 160 eV for survey spectra and then with 20 eV for region spectra. Survey spectra were recorded at intervals of 1.0 eV/step, while the region spectra were taken at intervals of 0.1 eV/step. The Shirley algorithm was used to measure the background core level spectra, and chemically distinct species in the high-resolution regions of the spectra were resolved using synthetic Gaussian–Lorentzian components after the background was removed using the Thermo Scientific Avantage Data System software (Thermo Fischer Scientific, Waltham, MA, USA). High-resolution scans were performed across each of the C 1s, O 1s, Ti 2p, K 2p peaks.

In parallel with the studies conducted above, Ti discs were exposed to 500 µg/ml solution of Teic in 50 mM MES, pH 5.47 and left, under ambient conditions from 30 min up to 3 h. To analyse elements on the surface of Ti and functionalised samples, XPS spectra were taken by using NEXSA XPS system (ThermoFisher, Waltham, MA, US). A monochromatic X-ray source (Al-Kα) beam was used for the data collection. The calculation of the atomic percentages was performed using Avantage Data System software (ThermoFisher, Waltham, MA, US).