Surface Activation of a Ferrimagnetic Glass-Ceramic for Antineoplastic Drugs Grafting

A ferrimagnetic glass-ceramic, belonging to the system SiO(2)-Na(2)O-CaO-P(2)O(5)-FeO-Fe(2)O(3), has been studied as potential carrier for antineoplastic agents, in order to exploit the combination of hyperthermia and chemotherapy. Different material pre-treatments, such as ultrasonic washing, water, or simulated body fluid dipping, were evaluated to promote the surface activation of the glass ceramic, i.e., the hydroxyl groups formation on it. X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersion spectrometry, and wettability measurements were performed to observe the samples surface modification. The best results in terms of free hydroxyl groups exposition were obtained by dipping the samples in distilled water for 7 days at 37 degrees C. Two different anticancer drugs were selected in order to test the reactivity of the activated surface: cisplatinum and doxorubicin. The uptake and release of doxorubicin and cisplatinum were evaluated on glass-ceramic powders, by using UV-Visible spectrometry and graphite furnace atomic absorption spectroscopy, respectively. After 1 day of uptake at 37 degrees C, the quantity of doxorubicin incorporated into the glass ceramic is 77 +/- 7 wt%, while only 42 +/- 9.6 wt% of cisplatinum is grafted onto the material surface. For both antitumoral agents, the maximum drug release after soaking in aqueous solutions at 37 degrees C was obtained in few hours, with a randomly distributed kinetics trend.