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A sol-gel process was used to synthesize class I organic-inorganic nanocomposite materials consisting of an inorganic ZrO2 matrix in which different percentages of polyethylene glycol (PEG) were incorporated. The formation of hydrogen bonds among the organic and inorganic components was proved by means of Fourier Transform Infrared Spectroscopy (FT-IR) analysis and 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) equipped with Back-Scattered Electron Detector (BSED) and Energy Dispersive X-ray (EDX) analysis showed that these materials have homogeneous morphology and nanostructured nature. Superconducting Quantum Interference Device (SQUID) magnetometry confirmed the expected diamagnetic character of these compounds. The measured diamagnetic susceptibility values, which increase with PEG amount and are independent from temperature, make these hybrid materials potentially suitable to be synthesized in magnetic levitation under microgravity conditions.

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.

Although metallic implants are the most used in dental and orthopaedic fields, they can early fail due to low tissue tolerance or osseointegration ability. To overcome this drawback, functional coatings can be applied on the metallic surface to provide a firm fixation of the implants. The objective of the present study was twofold: to synthesize and to characterize silica/polyethylene glycol (PEG) hybrid materials using sol-gel technique and to investigate their capability to dip-coat titanium grade 4 (Ti-gr4) substrates to improve their biological properties. Various hybrid systems have been synthesized by changing the ratio between the organic and inorganic phases in order to study the influence of the polymer amount on the structure and, thus, on the properties of the coatings. Fourier transform infrared (FTIR) spectroscopy and solid state Nuclear Magnetic Resonance (NMR) allowed us to detect the formation of hydrogen bonds between the inorganic sol-gel matrix and the organic component. SEM analysis showed that high PEG content enables to obtain crack free-coating. Moreover, the effective improvement in biological properties of Ti-gr4 implants has been evaluated by performing in vitro tests. The bioactivity of the hybrid coatings has been showed by the hydroxyapatite formation on the surface of SiO2/PEG coated Ti-gr4 substrates after soaking in a simulated body fluid and the lack of cytotoxicity by the WST-8 Assay. The results showed that the coated substrates are more bioactive and biocompatible than the uncoated ones and that the bioactivity is not significantly affected by PEG amount whereas its addition makes the films more biocompatible.

Controlled and local drug delivery systems of anti-inflammatory agents are attracting an increasing attention because of their extended therapeutic effect and reduced side effects. In this work, the sol-gel process was used to synthesize zirconia/polyethylene glycol (ZrO2/PEG) hybrid materials containing indomethacin for controlled drug delivery. Different percentages of PEG were introduced in the synthesis to modulate the release kinetic and an exhaustive chemical characterization of all samples was performed to detect the relationship between their structure and release ability. Fourier transform spectroscopy and solid-state NMR show that the Zr-OH groups of the inorganic matrix bond both the ethereal oxygen atoms of the polymer and the carboxylic groups of the drug. X-ray diffraction analysis ascertains the amorphous nature of those materials. Scanning electron microscopy detects the nanostructure and the homogeneous morphology of the synthesized materials. The bioactivity was demonstrated by the formation of a hydroxyapatite layer on the surface of the samples, after soaking in a simulated body fluid. The release kinetics study, performed by HPLC UV-Vis spectroscopy, proves that the release ability depends on PEG and the drug amount and also demonstrates the indomethacin integrity after the synthetic treatment

Organic-inorganic nanocomposite materials have been synthesized via sol-gel. They consist of an inorganic SiO2 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 SiO2/PCL hybrid materials are diamagnetic and that their diamagnetic susceptibility is independent of temperature and increases with the PCL amount