Preparation of sol-gel organic-inorganic hybrid coatings for controlled drug release

The need to improve the tolerability and life time of the metallic implants, lead our research group to develop implantable therapeutic systems able to release an anti-inflammatory agent in the implant site. Therefore, in the present work, a sol-gel dip coating route has been optimized to coat titanium implant with two organic-inorganic hybrid materials: the first consisted of a glass zirconia matrix in which indomethacin (IND) was embedded, the second of a zirconia glass, the polyester poly (ϵ-caprolactone) (PCL) and the IND. PCL was added into the materials to modulate the release kinetic of the IND. Moreover, coatings consisting of a different numbers of layers, were applied to a substrates to modulate the dosage of the released drug. The obtained coatings were characterized and the drug release was investigated as a function of the PCL content and of the layers' number

Sol-Gel Processing for new silica based materials functionalized with chlorogenic acid

The aim of the present study was to synthetize new phenol-based materials through the sol gel approach. 5-O-ceaffeoyl quinie acid, a natural antioxidant better known as chlorogenic acid (CGA), was incorporated within silica matrix obtaining orange colored hybrid materials, characterized by Fourier Transform InfraRed (FTIR) and Ultra Violet-Visible (UV-Vis) spectroscopic techniques. In vitro soaking tests in simulated body fluid (SI3F) was performed to evaluate the new materials' bioactivity and the formation of a hydroxyapatite layer was observed on the hybrid surface by SEM/EDX analysis. Moreover, CGA-based materials were biocompatible to murine and mammalian cells as assessed by tetrazolium dye (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)-based microtitration assay (MIT assay) and exerted antioxidant capability by scavenging DPPH and ARTS(+) radicals

Biomaterials Containing the Natural Antioxidant Quercetin: Synthesis and Health Benefits

Quercetin, whose health-promoting effects are acclaimed, is entrapped in a silica-based and silica/polymer hybrid material via sol–gel route, to develop new antioxidant biomaterials for preventing the onset of ROS-related diseases. The materials’ morphology is detected by SEM analysis, whereas the chemical characterization is achieved by spectroscopic and spectrometric techniques. Despite an oxidation reaction in the quercetin structure, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2′-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid)] data show that all the materials preserve its antioxidant efficacy. MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] test indicates a mild cytotoxicity in NIH-3T3, PC12, and U251 cells. Furthermore, materials with the highest quercetin percentage are able to inhibit the H2O2-induced intracellular ROS production in murine fibroblasts

Biomaterials Containing the Natural Antioxidant Quercetin: Synthesis and Health Benefits

Quercetin, whose health-promoting effects are acclaimed, is entrapped in a silica-based and silica/polymer hybrid material via sol–gel route, to develop new antioxidant biomaterials for preventing the onset of ROS-related diseases. The materials’ morphology is detected by SEM analysis, whereas the chemical characterization is achieved by spectroscopic and spectrometric techniques. Despite an oxidation reaction in the quercetin structure, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2′-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid)] data show that all the materials preserve its antioxidant efficacy. MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] test indicates a mild cytotoxicity in NIH-3T3, PC12, and U251 cells. Furthermore, materials with the highest quercetin percentage are able to inhibit the H2O2-induced intracellular ROS production in murine fibroblasts

The Influence of Polymer on Fe(II)Citrate Release from Hybrid Materials Synthesized via Sol–Gel

An ideal drug delivery system is developed to provide the therapeutic amount of a drug at the appropriate site in the body and to maintain the desired drug concentration. Interactions between drugs and the sol–gel system can affect the rate of release. The aim of this work is the synthesis of iron(II)-based therapeutic systems. The use of oral iron integration is commonly recommended for the treatment of iron deficiency; nevertheless the diagnosis and treatment of this disease can clearly be improved. The hybrids are synthesized by sol–gel method. In an SiO2 matrix, different weight percentages of polyethylene glycol (PEG6,12,24 wt%) and ferrous citrate (Fe(II)C5,10,15 wt%) are incorporated for drug delivery applications. The interactions among different components in the hybrid materials are evaluated by Fourier transform infrared spectroscopy. In order to quantify the release kinetics, the hybrids are soaked in a simulated body fluid, for different time points, and the amount of Fe2+ released in from several materials is detected by ultraviolet–visible spectroscopy after reaction with ortho-phenanthroline

Chlorogenic acid/PEG-based organic-inorganic hybrids: A versatile sol-gel synthesis route for new bioactive materials

New organic-inorganic hybrid materials were synthesized by an acid catalysed sol-gel approach, using silicon alkoxide and low molecular weight polyethylene glycol (PEG400) as inorganic and organic precursor, respectively. Chlorogenic acid (CGA), an antioxidant natural phenol compound, enriched further the organic component. Hybrids synthesized, all identical in terms of their starting materials, but differing in terms of their relative proportions, were characterized by means of Fourier Transform InfraRed (FTIR) measurements, UV–Vis spectroscopy, and UHPLC-HRMS analysis. The preservation of the intrinsic chlorogenic acid ability to scavenge, in a dose-dependent manner, radical species was investigated by directly exposing the hybrids to DPPH radical and ABTS radical cation. The relative ratio of both the natural compound and PEG heavily affected the antiradical response, suggesting that chemical interactions in the established network were able, based on components’ ratio, to differently mask and/or display the CGA moieties, commonly deemed relevant for antioxidant power exerting. Cell culture MTT assay was used to assess the biocompatibility of hybrid materials towards fibroblast NIH-3 T3 cells and neuroblastoma SH-SY5Y cells. Cells tested appeared differently responsive. In particular, a marked cell viability increase was observed when hybrids with low PEG amount (6%) and high CGA (15%) were directly exposed to fibroblast cells, whose mitochondrial redox activity was negatively affected by hybrid synthesized using the highest organic component rate (both PEG and CGA). Cell viability and morphology of human neuroblastoma SH-SY5Y cells were broadly compromised regardless of organic/inorganic starting materials ratio, suggesting the ability of hybrids to exert pro-oxidant effect towards tumour cells and to selectively interfere with their growth. The hybrids, able to elicit cleverly anti- or proliferative effects, were also shown to be bioactive. In fact, a biologically active hydroxyapatite layer was observed to be formed on the surface of the smart synthesized materials. This feature, which makes them a valuable bonding interface with tissues, opens new scenario aiming at further investigating the employment of natural phenol compounds in versatile sol–gel synthesis routes