Gallic acid grafting to a ferrimagnetic bioactive glass-ceramic

Abstract

Ferrimagnetic bioactive glass ceramics are promising biomaterials in the field of bone substitution and cancer treatment for their ability to bond to bone (bioactive behavior) and to be heated by the application of an external magnetic field (hyperthermia). Surface functionalization of these materials with polyphenols is a challenging and innovative strategy in order to impart them additional functional and specific properties (e.g. antioxidant, anticancer and antibacterial). Gallic acid (GA) is a phenolic acid which can be considered a good model molecule for polyphenols due to its simple structure and representative properties. In the present paper GA has been grafted to a ferrimagnetic glass ceramic (SC-45), in bulk and powder forms, in view of its potential clinical applications (such as hyperthermic treatment of cancer combined with the anticancer action of GA). The grafting process has been optimized in order to preserve GA activity. The effectiveness of the functionalization procedure has been demonstrated by means of Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric analysis-gas evolved analysis (TGA-EGA) and Folin&Ciocalteu tests (F&C). Release tests have been performed in double distilled water at 37°C and 43°C to verify the stability of the material.