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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.

Many studies reported that the use of gravity-free environments to improve some industrial processes. The sol-gel method is ideal technology to design of new organic-inorganic hybrid materials by entrapping various organic polymers in a glassy matrix for aerospace field. Two different hybrid materials were prepared. The SiO2and ZrO2were used as inorganic matrix, in which different percentages of polyethylene glycol (PEG) and poly(ϵ-caprolactone) (PCL) were incorporated, respectively. The chemical structure of the obtained materials was investigated by Fourier transform infrared (FTIR) spectroscopy, X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). Furthermore, in order to understand how the diamagnetic susceptibility is influenced by variation of both the inorganic matrix and organic component was used the Superconducting Quantum Interference Device (SQUID) magnetometry.

An interesting research field with medical applications is represented today by ceramics, as they can be used to obtain useful biomaterials for the production of implants (Vallet-Regi, 2001, 2006a, 2006b, 2006c); many parts of the human body, in fact, can be replaced or repaired with biomaterials and more specifically with bioceramics (Black & Hastings, 1998). Regardless of the ceramic type and the application procedure, the introduction of an implant in a living body always causes inflammation phenomena and frequently infection processes as well. Those problems can be overcome by using local drug delivery methods to confine pharmaceuticals such as antibiotics, anti-inflammatory, anti-carcinogens, etc. (Arcos et. al., 2001; Ragel & Vallet-Regi, 2000; Vallet-Regi et al., 2000). The possibility of introducing certain drugs into the ceramic matrices employed for bone and teeth repair is undoubtedly an added value to be taken into account. The traditional use of high temperature procedures to model glasses and ceramics to the desired shape is very well known; on the other hand, the degradation temperature of a pharmaceutical compound is usually around 100°C, which is very low if compared with the high ones needed to compact the components (around 1000°C). Consequently, the main problem is how to include pharmaceuticals in conventional glass and ceramic implants. The scientific community is currently investigating new procedures to incorporate drugs into implantable biomaterials. The sol-gel process, among others, has proved to be a versatile one and has been widely used in the preparation of amorphous and or hybrid materials (Hench & West, 1990; Judeinstein & Sanchez, 1996; Novak, 1993), with applications, for example, in non-linear optical materials (Hsiue et al., 1994) and mesomoporous materials (Wei et al., 1999). The family of organicinorganic hybrid materials has attracted considerable attention because of its interesting properties such as molecular homogeneity, transparency, flexibility and durability. A key issue that remains unresolved in these organic-modified materials is the degree of mixing of the organic-inorganic components, i.e., phase homogeneity. The high optical transparency to visible light indicates that the organic-inorganic phase separation, if any, is on a scale of ≤ 400nm. Such hybrids are promising materials for various applications, e.g.: solid state lasers (optical components), replacements for silicon dioxide as insulating materials in the

SiO2-based organic-inorganic hybrids (OIHs) are versatile materials whose properties may change significantly because of their thermal treatment. In fact, after their preparation at low temperature by the sol-gel method, they still have reactive silanol groups due to incomplete condensation reactions that can be removed by accelerating these processes upon heating them in controlled experimental conditions. In this study, the thermal behavior of pure SiO2 and four SiO2-based OIHs containing increasing amount (6, 12, 24 and 50 wt %) of poly(ε-caprolactone) (PCL) has been studied by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC). The FTIR analysis of the gas mixture evolved at defined temperatures from the samples submitted to the TG experiments identified the mechanisms of thermally activated processes occurring upon heating. In particular, all samples already release ethanol at low temperature. Moreover, thermal degradation of PCL takes place in the richest-PCL sample, leading to 5-hexenoic acid, H2O, CO2, CO and ε-caprolactone. After the samples' treatment at 450, 600 and 1000 °C, the X-ray diffraction (XRD) spectra revealed that they were still amorphous, while the presence of cristobalite is found in the richest-PCL material. © 2018 by the authors.

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.

Geopolymers are inorganic aluminosilicates mainly proposed as environmentally friendly building materials, which are obtained by alkali activation of natural minerals, calcined clay (e.g., metakaolin) and other aluminosilicate sources. The wide range of chemical and mineralogical compositions of these raw materials influences several properties of the obtained geopolymers. In the present work, pure Al2O3·2SiO2 powders were synthesized via the sol-gel technique and proposed as pure aluminosilicate sources to prepare alkali activated geopolymers. Samples differing in the ratio between the SiO2 precursor and the H2O used in the sol-gel process were prepared, in order to study the effect of water content on the material structure and reactivity. The chemical structure of all the obtained Al2O3·2SiO2 powders were characterized by Fourier transform infrared (FT-IR) and solid-state nuclear magnetic resonance (27Al and 29Si MAS NMR) spectroscopies and compared to that of a reference metakaolin. Moreover, material reactivity was evaluated by alkali activation of the samples. After 28 days of ageing, 27Al and 29Si MAS NMR and FT-IR spectra ascertained the formation of a geopolymeric network in the activated samples. The results showed that lower water content allows obtaining a homogeneous Al-rich geopolymer similar to that obtained, using metakaolin as raw material.

Organic–inorganic nanocomposite materials have been synthesized via sol–gel. They consist of an inorganic SiO 2 matrix, in which different percentages of poly(e-caprolactone) (PCL) have been incorporated. The formation of H-bonds among the carbonyl groups of the polymer chains and Si–OH group of the inorganic matrix has been proved by means of Fourier transform infrared spectroscopy (FT-IR) analysis and has been confirmed by solid-state nuclear magnetic resonance (NMR). X-Ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials. Scanning electron microscope (SEM) micrograph and atomic force microscope (AFM) topography showed their homogeneous morphology and nanostructure nature. Considering the opportunity to synthesize these hybrid materials under microgravity conditions by means of magnetic levitation, superconducting quantum interference device (SQUID) magnetometry has been used to quantify their magnetic susceptibility. This measure has shown that the SiO 2 /PCL hybrid materials are diamagnetic and that their diamagnetic susceptibility is independent of temperature and increases with the PCL amount.

Purpose: The importance of polymer-based composite materials to make multifunctional substrates for tissue engineering and the strategies to improve their performances have been stressed in the literature. Bioactive features of sol-gel synthesized poly(epsilon-caprolactone)/TiO(2) or poly(epsilon-caprolactone)/ZrO(2) organic-inorganic hybrid materials are widely documented. Accordingly, the aim of this preliminary research was to develop advanced composite substrates consisting of a poly(epsilon-caprolactone) matrix reinforced with sol-gel synthesized PCL/TiO(2) or PCL/ZrO(2) hybrid fillers. Methods: Micro-computed tomography and atomic force microscopy analyses allowed to study surface topography and roughness. On the other hand, mechanical and biological performances were evaluated by small punch tests and Alamar Blue (TM) assay, respectively. Results: Micro-computed tomography and atomic force microscopy analyses highlighted the effect of the preparation technique. Results from small punch tests and Alamar Blue (TM) assay evidenced that PCL reinforced with Ti2 (PCL=12, TiO(2) = 88 wt%) and Zr2 (PCL=12, ZrO(2) = 88 wt%) hybrid fillers provided better mechanical and biological performances. Conclusions: PCL reinforced with Ti2 (PCL=12, TiO(2) = 88 wt%) and Zr2 (PCL=12, ZrO(2) = 88 wt%) hybrid fillers could be considered as advanced composite substrates for hard tissue engineering.