Sol–gel synthesis and thermal behavior of bioactive ferrous citrate–silica hybrid materials

Imbalance of the iron level in the body causes several diseases. In particular, the low level of iron, during pregnancy, is responsible for the iron deficiency anemia, and even of neurodegenerative diseases. Although the treatment of iron deficiency anemia with oral iron supplements has been known, this problem still afflicts many people. The aim of this work was the development of a system able to release ferrous ions in a controlled manner. Controlled drug release for medical applications, indeed, appears to be a very interesting alternative to a systemic therapy because it is assurance of treatment continuity and drug stability and optimizes drug absorption. For this purpose, ferrous citrate (Fe(II)C) was synthesized by a redox reaction between iron powder and citric acid. Fourier transform infrared spectroscopy (FTIR), 1,10-phenanthroline and sodium thiocyanate colorimetric assays confirmed that only Fe(II)C was obtained by redox reaction. Afterward, obtained Fe(II)C was embedded within a SiO2 matrix in different mass percentage, by means of a sol–gel route. FTIR spectroscopy and simultaneous thermogravimetry/first-order derivative of thermogravimetry were used to confirm the Fe(II)C presence in the silica matrix and to investigate the thermal behavior of the sol–gel materials, respectively. The bioactivity test carried out by soaking the synthesized drug delivery systems in a simulated body fluid showed that the biological properties of the silica matrix are not modified by the presence of Fe(II)C

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 N2flowing 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

Sol–Gel Method Applied to Crystalline Materials

Sol–gel chemistry is a versatile synthesis used to produce modern materials at nearroom temperature. Glasses, ceramics, composites, and new hybrid materials that are not easy to obtain using other methods have been, instead, obtained in the last three decades and nowadays are widely used. Changing the chemical composition, many parameters of the sol-gel process can be adapted to control the properties and the microstructure of the obtained materials. Sol-gel technology is a multidisciplinary science which allows the expansion of materials for many applications. In this Special Issue, special attention is paid to the properties of materials obtained by using sol–gel methods and to their potential applications in environmental science and materials science as in catalysis, optics, electronics, energy, biosensors, medicine, and so on

Surface Interactions between Ketoprofen and Silica‐Based Biomaterials as Drug Delivery System Synthesized Via Sol–Gel: A Molecular Dynamics Study

Biomaterial‐based drug delivery systems for a controlled drug release are drawing in‐ creasing attention thanks to their possible pharmaceutical and biomedical applications. It is im‐ portant to control the local administration of drugs, especially when the drug exhibits problems diffusing across biological barriers. Thus, in an appropriate concentration, it would be released in situ, reducing side effects due to interactions with the biological environment after implantation. A theoretical study based on Molecular Mechanics and Molecular Dynamics methods is performed to investigate possible surface interactions between the amorphous SiO2 surface and the ketoprofen molecules, an anti‐inflammatory drug, considering the role of drug concentration. These theoretical results are compared with experimental data obtained by analyzing, through Fourier transform infrared spectroscopy (FT‐IR), the interaction between the SiO2 amorphous surface and two per‐ centages of the ketoprofen drug entrapped in a silica matrix obtained via the sol–gel method and dried materials. The loaded drug in these amorphous bioactive material forms hydrogen bonds with the silica surface, as found in this theoretical study. The surface interactions are essential to have a new generation of biomaterials not only important for biocompatibility, with specific structural and functional properties, but also able to incorporate anti‐inflammatory agents for re‐ lease into the human bod

Hydration of triethylenetetramine based inhibitor film accelerates the chloride-induced corrosion in concrete: a molecular dynamics study

Abstract. Organic corrosion inhibitors can be used to prevent chloride-induced corrosion in reinforced concrete structures. In this theoretical study Molecular Mechanics (MM) and Molecular Dynamics (MD) simulations are performed in order to better understand the interaction mechanisms with the passive film present on steel [1], in particular considering γ-FeOOH surface as solid surface which can be subject to chloride-induced corrosion process and the dimethylethanolamine (TETA) film [2]. The MD simulations are a very useful tool because they describe at atomistic level both the solid surface and organic inhibitors molecules in presence of chloride ions [2] and water molecules [3]. Hydration of organic TETA inhibitor film in presence of chloride ions always accelerate the corrosion process, as experimentally well known. In this theoretical work water molecules in fact induce chloride ions to adsorb on γ-FeOOH surface more quickly and in greater numbers respect with to the same simulations study without water molecules. This kind of organic film cannot exhibit a good behavior to prevent the chloride-induced corrosion process not displaying the so important repulsion to chloride ions. The hydration accelerates the corrosion process. This theoretical work permit to compare these results with another organic inhibitors films studied in previous work [1] in order to prevent the corrosion. References [1] M.V. Diamanti, E. A. Pérez-Rosales, G. Raffaini, F. Ganazzoli, A. Brenna, M. Pedeferri, M. Ormellese, Corrosion Science, 100, 231-241 (2015). [2] G. Raffaini, M. Catauro, F. Ganazzoli, F. Bolzoni, M. Ormellese, Macromolecular Symposia, 395, Article Number: 2000231, pp. 1-3 (2021). [3] G. Raffaini, F. Ganazzoli, J. of Biomed. Mat. Res. PART A, 92A, 1382-1391 (2006)

Geopolymers—Design, Preparation, and Applications

Concrete is the most commonly used construction material worldwide, and many efforts have been carried out in recent years to improve its functional properties while also trying to increase its sustainability [...

Thermal, chemical and antimicrobial characterization of bioactive titania synthesized by sol–gel method

Chemical stability, anticorrosive properties and photocatalytic activity of titanium dioxide (TiO 2 ) are among the most important characteristics for industrial and environmental applications. It is well known that titanium biomaterials’ proper- ties and response depend significantly on the synthesis method. This work reports the sol–gel synthesis of TiO 2 particles, followed by the studies of their structure, thermal analysis and antimicrobial properties. The main issues were to evaluate the chemical structure of the particles by Fourier transform infrared spectroscopy, the thermal behavior by thermogravimetric analysis and the particle size of the TiO 2 by SEM and BET experiments. In particular, this characterization aims at verify- ing the possibility to use these materials to prevent infections after implantation. The antibacterial activity of TiO 2 particles was assessed using Escherichia coli and Enterococcus faecalis. Finally, the bioactivity of TiO 2 particles were estimated by soaking them for 21 days in simulated body fluid with the view to evaluate their biological properties

Characterization of Hybrid Materials Prepared by Sol-Gel Method for Biomedical Implementations. A Critical Review

The interaction between tissues and biomaterials (BM) has the purpose of improving and replacing anatomical parts of the human body, avoiding the occurrence of adverse reactions in the host organism. Unfortunately, the early failure of implants cannot be currently avoided, since neither a good mixture of mechanical and chemical characteristics of materials nor their biocompatibility has been yet achieved. Bioactive glasses are recognized to be a fine class of bioactive substances for good repair and replacement. BM interact with living bones through the formation of a hydroxyapatite surface layer that is analogous to bones. Bioglasses’ composition noticeably affects their biological properties, as does the synthesis method, with the best one being the versatile sol-gel technique, which includes the change of scheme from a ‘sol’ fluid into a ‘gel’. This process is widely used to prepare many materials for biomedical implants (e.g., hip and knee prostheses, heart valves, and ceramic, glassy and hybrid materials to serve as carriers for drug release). Nanoparticles prepared by the sol-gel method are interesting systems for biomedical implementations, and particularly useful for cancer therapy. This review provides many examples concerning the synthesis and characterization of the above-mentioned materials either taken from literature and from recently prepared zirconia/polyethylene glycol (PEG) hybrids, and the corresponding results are extensively discussed

FT-IR characterization of antimicrobial hybrid materials through sol-gel synthesis

Silica/polycaprolactone and titania/polycaprolactone hybrid organic/inorganic amorphous composites were prepared via a sol-gel method starting from a multi-element solution containing tetramethyl orthosilicate (TMOS) or titanium butoxide (TBT), polycaprolactone (PCL), water and methylethylketone (MEK). The molecular structure of the crosslinked network was based on the presence of the hydrogen bonds between organic/inorganic elements as confirmed by Fourier Transform Infra-Red (FT-IR) analysis. In particular, the structure of crosslinked network was realized by hydrogen bonds between the X-OH (X = Si or Ti) group (H donator) in the sol-gel intermediate species and ester groups (H-acceptors) in the repeating units of the polymer. The morphology of the hybrid materials; pore size distribution, elemental homogeneity and surface features, was studied by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and by atomic force microscopy (AFM). The bioactivity of the synthesized hybrid materials was confirmed by observing the formation of a layer of hydroxyapatite (HAP) on the surface of the samples soaked in a simulated body fluid. The antimicrobial behavior of synthetized hybrids was also assessed against Escherichia coli bacteria. In conclusion, the prepared hybrid materials are proposed for use as future bone implants