The failure of medical devices, such as bones prosthesis, is mainly due to inflammatory and infectious phenomena. Entrapping anti-inflammatory and antimicrobial agents inside the biomaterial matrix could avoid these phenomena. In this context, inorganic/organic silica (S)/polyethylene glycol (P)/caffeic acid (A) hybrid systems were synthesized via the sol-gel method with different weight percentages of P and A. Fourier-transform infrared (FT-IR) revealed that caffeic acid undergoes an oxidizing phenomenon in the sol-gel synthesis condition. Additionally, the formation of a hydroxyapatite layer on hybrid surfaces was demonstrated by employing the Kokubo test and analyzing the samples using scanning electron microscopy, X-ray diffraction, and FT-IR. Moreover, further characterization of the antimicrobial activity of the synthesized biomaterials was carried out using the Kirby–Bauer test. Finally, UV-Vis measurement was useful to evaluate the caffeic acid kinetic release in simulated body fluid (SBF) at 37 °C. The kinetic study disclosed that the hybrid materials without polyethylene glycol had faster release rates than the ones obtained without the organic polymer.

Burning wood is estimated to produce about 6–10% of ash. Despite the possibility of recycling wood ash (WA), approximately 70% of the wood ash generated is landfilled, causing costs as well as environmental pollution. This study aims to recycle WA in an alternative way by inserting it as filler in geopolymeric materials. Here, metakaolin, NaOH, sodium silicate, and WA are used to realize geopolymers. Geopolymers without and with 10, 20 and 30% of WA are synthesized and characterized after 7, 14, 28 and 56 days. The article’s study methods are related to geopolymers’ chemical, biological and mechanical properties. The geopolymers synthesized are compact and solid. The pH and conductivity tests and the integrity and weight loss tests have demonstrated the stability of materials. The FT-IR study and boiling water test have confirmed the successful geopolymerization in all samples. The antibacterial analysis, the moss growing test and the compressive strength test have given a first idea about the durability of the materials synthesized. Furthermore, the compressive strength test result has allowed the comparison from the literature of the specimens obtained with the Portland cement (PC). The results obtained bode well for the future of this material.

This paper aims to synthesize, via the sol–gel method, a biomaterial usable in the medical field. Here, the silica-PEG-quercetin system was evaluated in relation to the different concentrations of PEG (0, 6, 12, 24, 50 wt%) and quercetin (0, 5, 10, 15 wt%), respectively. In addition, Fourier Transform-Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Kirby–Bauer analyses were performed. FT-IR was used to evaluate the hybrid formation and the influence of both PEG and Quercetin in the hybrid synthesized materials, SEM was used to evaluate the morphological properties, while the Kirby–Bauer test was used to understand the ability of the materials to inhibit the growth of the assayed bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus).

The increasing global demand for cement significantly impacts greenhouse gas emissions and resource consumption, necessitating sustainable alternatives. This study investigates fresh geopolymer (GP) pastes incorporating 20 wt.% of five industrial wastes—suction dust, red mud from alumina production, electro-filter dust, and extraction sludges from food supplement production and from partially stabilized industrial waste—as potential replacements for traditional cement. Consistent synthesis methods are used to prepare the geopolymers, which are characterized for their physicochemical, mechanical, and biological properties. Ionic conductivity and pH measurements together with integrity tests, thermogravimetry analysis (TGA), and leaching analysis are used to confirm the stability of the synthesized geopolymers. Fourier-transform Infrared (FT-IR) spectroscopy is used to follow geopolymerization occurrences. Results for ionic conductivity, pH, and integrity revealed that the synthesized GPs were macroscopically stable. TGA revealed that the main mass losses were ascribable to water dehydration and to water entrapped in the geopolymer networks. Only the GP filled with the powder of the red mud coming from alumina production experienced a mass loss of 23% due to a partial waste degradation. FT-IR showed a red shift in the main Si-O-(Si or Al) absorption band, indicating successful geopolymer network formations. Additionally, most of the GPs filled with the wastes exhibited higher compressive strength (37.8–58.5 MPa) compared to the control (22 MPa). Only the GP filled with the partially stabilized industrial waste had a lower mechanical strength as its structure was highly porous because of gas formation during geopolymerization reactions. Despite the high compressive strength (58.5 MPa) of the GP filled with suction dust waste, the concentration of Sb leached was 25 ppm, which limits its use. Eventually, all samples also demonstrated effective antimicrobial activity against Escherichia coli and Staphylococcus aureus due to the alkaline environment and the presence of metal cations able to react with the bacterial membranes. The findings revealed the possibility of recycling these wastes within several application fields.

Hybrid materials, composed of organic and inorganic components at the nanometer or molecular level, have emerged as a promising material class at the forefront of technological progress. Their potential applications in the biological and medical fields have garnered significant interest, particularly in the context of incorporating antioxidant compounds. This study focuses on the synthesis and characterization of a sol–gel-derived hybrid material, consisting of silica (S), polyethylene glycol (P), and the antioxidant flavonoid quercetin (Q). By varying the concentrations of Q and P, the structural and biological properties of the SPQ hybrid systems were investigated. Structural analysis using Fourier-transform infrared (FT-IR) and solid-state nuclear magnetic resonance (NMR) spectroscopies provided insights into the material composition and morphology, giving information about the interactions between the organic and inorganic phases. Additionally, the in vitro release study revealed a controlled release of quercetin over time, demonstrating that the hybrid materials possess a suitable application for drug delivery.