Elisabetta Tranquillo

Zirconia/Hydroxyapatite Composites Synthesized Via Sol-Gel: Influence of Hydroxyapatite Content and Heating on Their Biological Properties

Zirconia (ZrO2) and zirconia-based glasses and ceramics are materials proposed for use in the dental and orthopedic fields. In this work, ZrO2 glass was modified by adding different amounts of bioactive and biocompatible hydroxyapatite (HAp). ZrO2/HAp composites were synthesized via the sol-gel method and heated to different temperatures to induce modifications of their chemical structure, as ascertained by Fourier transform infrared spectroscopy (FTIR) analysis. The aim was to investigate the effect of both HAp content and heating on the biological performances of ZrO2. The materials’ bioactivity was studied by soaking samples in a simulated body fluid (SBF). FTIR and scanning electron microscopy (SEM)) analyses carried out after exposure to SBF showed that all materials are bioactive, i.e., they are able to form a hydroxyapatite layer on their surface. Moreover, the samples were soaked in a solution containing bovine serum albumin (BSA). FTIR analysis proved that the synthesized materials are able to adsorb the blood protein, the first step of cell adhesion. WST-8 ([2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt]) assay showed that no cytotoxicity effects were induced by the materials’ extract. However, the results proved that bioactivity increases with both the HAp content and the temperature used for the thermal treatment, whereas biocompatibility increases with heating but is not affected by the HAp content.

The Influence of the Polymer Amount on the Biological Properties of PCL/ZrO2 Hybrid Materials Synthesized via Sol-Gel Technique

Organic/inorganic hybrid materials are attracting considerable attention in the biomedical area. The sol-gel process provides a convenient way to produce many bioactive organic–inorganic hybrids. Among those, poly(e-caprolactone)/zirconia (PCL/ZrO2) hybrids have proved to be bioactive with no toxic materials. The aim of this study was to investigate the effects of these materials on the cellular response as a function of the PCL content, in order to evaluate their potential use in the biomedical field. For this purpose, PCL/ZrO2 hybrids containing 6, 12, 24, and 50 wt % of PCL were synthesized by the sol-gel method. The effects of their presence on the NIH-3T3 fibroblast cell line carrying out direct cell number counting, MTT, cell damage assays, flow cytometry-based analysis of cell-cycle progression, and immunoblotting experiments. The results confirm and extend the findings that PCL/ZrO2 hybrids are free from toxicity. The hybrids containing 12 and 24 wt % PCL, (more than 6 and 50 wt % ones) enhance cell proliferation when compared to pure ZrO2 by affecting cell cycle progression. The finding that the content of PCL in PCL/ZrO2 hybrids differently supports cell proliferation suggests that PCL/ZrO2 hybrids could be useful tools with different potential clinical applications.

Sol-Gel Synthesis, Spectroscopic and Thermal Behavior Study of SiO2/PEG Composites Containing Different Amount of Chlorogenic Acid

In this work, new phenol-based materials have been synthesized by the sol-gel method, in which different amounts of the phenolic antioxidant chlorogenic acid (CGA) (from 5 wt % to 20 wt %) were embedded in two different silica matrices: pure silica and silica-based hybrids materials, containing 50 wt % of polyethylene glycol (PEG). The incorporation of CGA in different sol-gel matrices might protect them from degradation, which could cause the loss of their properties. The two series of materials were chemically characterized by Fourier transform infrared (FTIR) spectroscopy. In addition, the thermal behavior of both series of materials containing CGA was studied by thermogravimetry under both air and inert N2 flowing gas atmosphere. The bioactivity was evaluated by soaking the synthesized hybrids in a simulated body fluid, showing that the bioactivity of the silica matrix is not modified by the presence of PEG and CGA.

Chemical analysis and anti-proliferative activity of Campania Thymus Vulgaris essential oil

Abstract In this study, the potential antitumor activity of an essential oil (EO) obtained from Thymus vulgaris L. plants cultivated in Campania (Southern Italy) was evaluated. The gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy were used to investigate the chemical composition of EO. The monoterpenes thymol, p-cymene and carvacrol are the more abundant compounds detected. The anti-proliferative activity of the EO as a function of dose and time of exposure was evaluated by MTT assay on human osteosarcoma U2OS and pancreatic cancer PANC-1 cell lines. EO inhibits proliferation of both cell lines, but the effect on PANC-1 cells was more extensive. Flow cytometry and Western blot analyses revealed that the anti-proliferative effect is due to a decrease of cells in the S phase and their accumulation in the G1 phase, associated with the decrease of cyclin A and the increase of cell cycle inhibitor p27 protein levels, respectively.

New insights into phenol and polyphenol composition of Stevia rebaudiana leaves

&NA; The diversity in phenols and polyphenols of stevia leaf has been simplified applying sequential fractionation techniques on its ethanol extract through ultrasound assisted maceration. Two of the fractions obtained by reverse‐phase column chromatography resulted differently active in an extensive antioxidant and cytotoxic screening. Both fractions were chemically profiled by ultra‐performance liquid chromatography (UHPLC) coupled with electrospray ionization (ESI) quadrupole/time‐of‐flight (QqTOF) mass spectrometry (MS). One of the fractions was composed mainly of chlorogenic acids and flavonol triglycosides, whereas the other was rich in flavonoids mono‐ and diglycosides and in their hydroxycinnamoyl derivatives. Among the fifty compounds identified, non‐phenol metabolites, such as benzyl primeveroside and roseoside, as well as a lignan polyphenol (5′), are reported for the first time as constituents of the Stevia leaf.

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 (e-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.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 (e-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.

Silica/Polyethylene Glycol Hybrid Materials Prepared by a Sol-Gel Method and Containing Chlorogenic Acid

Chlorogenic acid (CGA) is a very common dietary polyphenolic compound. CGA is becoming very attractive due to its potential use as preventive and therapeutic agent in many diseases, including cancer. Inorganic/organic hybrid materials are gaining considerable attention in the biomedical field. The sol-gel process provides a useful way to obtain functional organic/inorganic hybrids. The aim of this study was to synthesize silica/polyethylene glycol (PEG) hybrids with different percentages of CGA by sol-gel technique and to investigate their impact on the cancer cell proliferation. Synthesized materials have been chemically characterized through the FTIR spectroscopy and their bioactivity evaluated looking by SEM at their ability to produce a hydroxyapatite layer on their surface upon incubation with simulated body fluid (SBF). Finally, their effects on cell proliferation were studied in cell lines by direct cell number counting, MTT, flow cytometry-based cell-cycle and cell death assays, and immunoblotting experiments. Notably, we found that SiO2/PEG/CGA hybrids exhibit clear antiproliferative effects in different tumor, including breast cancer and osteosarcoma, cell lines in a CGA dependent manner, but not in normal cells. Overall, our results increase the evidence of CGA as a possible anticancer agent and illustrate the potential for clinical applications of sol-gel synthesized SiO2/PEG/CGA materials.