New multifunctional surfaces from the coupling of biomaterials with plant derived natural molecules

Introduction: Plant derived biomolecules have a positive effect on human health and can be extracted from the waste of food and wine industry in a sustainable way. They are promising agents to modulate inflammatory response, to improve fast osseointegration, to kill cancerous cells and to avoid biofilm formation. In order to overcome their poor effect when administrated through systemic way, they can be grafted to biomaterial or used as coatings in order to exploit their actions in loco. Aim: The aim of the work is to combine the properties of plant derived biomolecules with those of biomaterials in order to enrich their surfaces with new beneficial properties. Materials and methods: Natural polyphenols extracted prom red wine pomace, tea leaves and mint essential oil were used to coat/ functionalize several biomaterials. Three different bioactive glasses with different degree of bioactivity, a surface treated bioactive titanium alloy and pellets of hydroxyapatite were functionalized with polyphenols; titanium alloy and stainless steel were coated/ functionalized with mint essential oil. The surfaces were characterized by means of Folin&Ciocalteu test, DPPH test, FTIR, fluorescence microscope observations, gaschromatographic analysis, XPS analysis and tape test. The surfaces were also tested with cell cultures and antibacterial tests. Results and discussion: F&C, DPPH, XPS and fluorescence microscope analyses confirmed the presence and redox activity of the polyphenols on the surfaces after grafting. XPS, FTIR and fluorescence microscope observations confirmed the success of the functionalization/coating with mint oil. The tape test showed the great stability of the coating. Gaschromatographic analysis also showed the ability of the chemically treated titanium alloy to selectively graft minorizing compound of the oil. Cell tests showed the ability of polyphenols to induce apoptosis in tumoral cells while they not had adverse effects on healthy ones. The antibacterial tests performed on samples treated with menta oil showed anti-adhesive action against bacteria. The results showed the success of the procedure of coating/ functionalization after developing of a specific protocol for each single material: this approach seems to be an effective way in order to efficiently exploit in loco the properties of natural molecules. Conclusions: This research highlighted the possibility to use natural molecules to confer new properties to biomaterials in order to cover currently unmet requirements. It also uses an environmental friendly approach recovering these biomolecules with high added value at low cost from the waste of food and wine industry. Acknowledgments: research grant from Fondazione Cassa di Risparmio di Torino (RF=2015.1681) and NAT4MORE project (funded by EC – M.ERA-NET) are acknowledged for supporting different research activities.