title: Silica/quercetin sol-gel hybrids as antioxidant dental implant materials.
abstract: The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing the onset of peri-implant diseases. In this context, quercetin, a naturally occurring flavonoid, has been entrapped at different weight percentages in a silica-based inorganic material by a sol-gel route. The establishment of hydrogen bond interactions between the flavonol and the solid matrix was ascertained by Fourier transform infrared spectroscopy. This technique also evidenced changes in the stretching frequencies of the quercetin dienonic moiety, suggesting that the formation of a secondary product occurs. Scanning electron microscopy was applied to detect the morphology of the synthesized materials. Their bioactivity was shown by the formation of a hydroxyapatite layer on sample surface soaked in a fluid that simulates the composition of human blood plasma. When the potential release of flavonol was determined by liquid chromatography coupled with ultraviolet and electrospray ionization tandem mass spectrometry techniques, the eluates displayed a retention time that was 0.5 min less than quercetin. Collision-activated dissociation mass spectrometry and untraviolet-visible spectroscopy were in accordance with the release of a quercetin derivative. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods, whereas the 2,7-dichlorofluorescein diacetate assay highlighted their ability to inhibit the H2O2-induced intracellular production of reactive oxygen species in NIH-3T3 mouse fibroblast cells. Data obtained, along with data gathered from the MTT cytotoxicity test, revealed that the materials that entrapped the highest amount of quercetin showed notable antioxidant effectiveness.
authors.affiliation: Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa, Italy.
authors.forename: Michelina
authors.initials: M
authors.lastname: Catauro
authors.affiliation: Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa, Italy.
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Papale
authors.affiliation: Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa, Italy.
authors.forename: Flavia
authors.initials: F
authors.lastname: Bollino
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Piccolella
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Sabina
authors.initials: S
authors.lastname: Marciano
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Nocera
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Severina
authors.initials: S
authors.lastname: Pacifico
keywords: antioxidant activity; bioactivity; biocompatibility; quercetin; sol–gel technique