Insight software

UV–vis measurements were performed at 480 nm (the maximum wavelength of the doxorubicin) using either an Evolution 220 UV–vis spectrophotometer equipped with Insight software (Thermo Scientific, Schwerte, Germany) or a UVD-3500 double bean spectrophotometer (Labomed, LA, USA). Standard rectangular quartz cells with 0.5 or 1 cm optical path were used. A calibration curve was used for measuring the concentration of doxorubicin (see Figure S1, Supplementary Materials).

The optical properties of the organic layers were investigated by UV–VIS spectroscopy using an Evolution 220 UV-VIS spectrophotometer equipped with Insight software (Thermo Scientific, Schwerte, Germany). The UV-VIS measurements were performed in absorption and transmission modes, in the 190–1100 nm range with 0.2 s integration time and with a scan speed of 300 nm/min.
The PL measurements were performed using an Edinburgh Instruments spectrometer with a 450 W Xe lamp. The PL spectra were recorded in the 450–850 nm range, at 435 nm excitation wavelength.

To obtain quantitative data on the release of IBUP from composite coatings during dynamic studies, the calibration curve of Ibuprofen was mandatory. Thus, we prepared an initial stock solution of 1 mg/mL IBUP in SBF (pH = 7.4). Complete dissolution of the drug was possible after sonication and vortexing, using in this respect the Elmasonic X-tra 30H ultrasonic bath from Elma Schmidbauer GmbH (Singen, Germany) and the Vortex Mixer from Velp Scientifica (Usmate, Italy), respectively. Starting from the stock solution, dilutions were made to obtain solutions with 0.75, 0.5, 0.25, 0.125 and 0.0625 mg/mL IBUP concentrations. All solutions were analyzed using the Evolution 220 UV-Vis spectrophotometer equipped with Insight software (Thermo Scientific, Schwerte, Germany). Measurements were performed in the absorbance mode, in the 200–400 nm wavelength range.