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

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

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

Molecular dynamics study of Sorafenib anti-cancer drug

Sorafenib (SOR) is an oral multikinase inhibitor which impedes proliferation, angiogenesis and invasion of cancer cells with low water-solubility. Amphiphilic cyclodextrins (aCD) have been investigated as a possible nanocarrier for systemic administration of SOR increasing its bio-availability [1]. A theoretical study about inclusion complexes of SOR drug and a model of aCD system using a simulation protocol based on Molecular Mechanics (MM) and Molecular Dynamics (MD) methods [2] is here reported. In this work we have studied at first the single model aCD (SC6OH, heptakis(2-O-oligo(ethylene oxide)-6-hexylthio)-β-CD bearing 14 units of ethylene-oxide at the CD secondary rim ) and the single molecule of SOR, then the formation of the complex in the dielectric environment [3]. The results data of final most stable geometry of the inclusion complex anticancer-cyclodextrin which showed the lowest potential and interaction energy were reported. The most stable host-guest geometry shows that the fluorine atoms of SOR drug are directed toward the hydrophobic primary rim of the aCD, while the part of the SOR rich in oxygen atoms is directed towards the hydrophilic secondary rim. References [1] M. L. Bondì, A. Scala, G. Sortino, E. Amore, C. Botto, A. Azzolina, D. Balasus, M. Cervello and A. Mazzaglia, Biomacromolecules, 2015, 16, 3784-3791. [2] G. Raffaini, F. Ganazzoli, L. Malpezzi, C. Fuganti, G. Fronza, W. Panzeri and A. Mele J. Phys. Chem B., 2009,113, 9110-9122

Addition of WEEE glass to metakaolin based geopolymeric binder: a cytotoxicity study

Waste Electrical and Electronic Equipment (WEEE) types of glass, including Cathode Ray Tube (CRT) glass, are now separately collected in European Union 28 (EU28) zone. Due to the high level of Pb and Ba in their compositions, this type of waste finds its way to the disposal. In the present research, a geopolymer matrix based on metakaolin is used to blend in fine powder panel and funnel glass from personal computer (PC) and television (TV) monitors. Such waste glass, which cannot be directed to glass melting furnaces, is safely incorporated into a geopolymer matrix. The consolidation of the geopolymeric matrix containing the waste glass was followed by pH and conductibility up to 28 days of curing. Scanning electron microscope equipped with energy dispersive spectroscopy (SEM/EDS) was used to obtain information on the microstructure of the consolidated products. Cytotoxicity tests helped the environmental evaluation of these materials