Metal–organic frameworks (MOFs) are a class of crystalline porous materials with outstanding physical and chemical properties that make them suitable candidates in many fields, such as catalysis, sensing, energy production, and drug delivery. By combining MOFs with polymeric substrates, advanced functional materials are devised with excellent potential for biomedical applications. In this research, Zeolitic Imidazolate Framework 8 (ZIF-8), a zinc-based MOF, was selected together with cellulose, an almost inexhaustible polymeric raw material produced by nature, to prepare cellulose/ZIF-8 composite flat sheets via an in-situ growing single-step method in aqueous media. The composite materials were characterized by several techniques (IR, XRD, SEM, TGA, ICP, and BET) and their antibacterial activity as well as their biocompatibility in a mammalian model system were investigated. The cellulose/ZIF-8 samples remarkably inhibited the growth of Gram-positive and Gram-negative reference strains, and, notably, they proved to be effective against clinical isolates of Staphylococcus epidermidis and Pseudomonas aeruginosa presenting different antibiotic resistance profiles. As these pathogens are of primary importance in skin diseases and in the delayed healing of wounds, and the cellulose/ZIF-8 composites met the requirements of biological safety, the herein materials reveal a great potential for use as gauze pads in the management of wound infections.

The development of green, low cost and sustainable synthetic routes to produce metal nanoparticles is of outmost importance, as these materials fulfill large scale applications in a number of different areas. Herein, snail slime extracted from Helix Aspersa snails was successfully employed both as bio-reducing agent of silver nitrate and as bio-stabilizer of the obtained nanoparticles. Several trials were carried out by varying temperature, the volume of snail slime and the silver nitrate concentration to find the best biogenic pathway to produce silver nanoparticles. The best results were obtained when the synthesis was performed at room temperature and neutral pH. UV–Visible Spectroscopy, SEM-TEM and FTIR were used for a detailed characterization of the nanoparticles. The obtained nanoparticles are spherical, with mean diameters measured from TEM images ranging from 15 to 30 nm and stable over time. The role of proteins and glycoproteins in the biogenic production of silver nanoparticles was elucidated. Infrared spectra clearly showed the presence of proteins all around the silver core. The macromolecular shell is also responsible of the effectiveness of the synthesized AgNPs to inhibit Gram positive and Gram negative bacterial growth.

Paper and cellulose-based materials are known for their sensitivity to humidity, which can create stresses among fibres and increase fragility. More importantly, humidity can lead to the formation of mould and stains, compromising both aesthetic value and long-term preservation, particularly for historical documents and books. This study explored the application of in situ prepared Zeolitic Imidazolate Framework (ZIF-8), a zinc-based MOF, on paper as a potential antimicrobial material. Hand-made and commercially printed papers were tested to assess the effective deposition and formation of the ZIF-8 network, with a focus on both visual appearance and physicochemical characteristics. X-ray fluorescence and diffraction, infrared spectroscopy, and scanning electron microscopy analysis confirmed the successful formation of the ZIF-8 network in all papers. The Zn content varied, as expected, depending on application time and paper characteristics. All treated papers exhibited minor variations in brilliance and showed slightly increased rigidity. The formation of white spots linked to Zn accumulation was observed, particularly in printed books where colourimetric and microscopic variations were more pronounced.

This work describes a simple, inexpensive, and robust method to prepare a flexible “all in one” integrated hydrogel supercapacitors (HySCs). Preparing smart hydrogels with high electrical conductivity, ability to stretch significantly, and excellent mechanical properties is the last challenge for tailored wearable devices. In this paper, we employed a physical crosslinking process that involves consecutive freezing and thawing cycles to prepare a polyvinyl alcohol (PVA)-based hydrogel. Exploiting the self-healing properties of these materials, the assembly of the different layers of the HySCs has been performed. The ionic conductivity within the electrolyte layer arises from the inclusion of an H₂SO₄ solution in the hydrogel network. Instead, the electronic conductivity is facilitated by the addition of the conductive polymer PANI-PAMPSA into the hydrogel layers. Electrochemical measures have highlighted newsworthy properties related to our HySCs, opening their use in wearable electronic applications.

This research study aims to explore the synergistic effects of incorporating polyvinylidene fluoride (PVDF) into polyvinyl alcohol (PVA) hydrogels to enhance their suitability for triboelectric sensors applications. The preparation process employs a method of freezing/thawing conducted in dimethyl sulfoxide (DMSO), followed by solvent replacement with water. This approach effectively preserves PVDF in its α phase, eliminating piezoelectric effects and enhancing the hydrogels’ mechanical properties. The use of DMSO contributes to reduced pore size, while incorporating PVDF significantly improves the three-dimensional network structure of the hydrogels, resulting in enhanced thermal and chemical resistance. Thorough characterization of the resulting PVA/PVDF composite hydrogels, prepared with varying ratios of PVA to PVDF (10:0, 8:2, and 5:5), was conducted by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), rheology, and thermogravimetric analysis (TGA). Notably, the composite hydrogels were tested in pressure sensors and human voice sensors, demonstrating their capability to recognize different patterns associated with various letters. The incorporation of PVDF significantly enhanced the signal-to-noise ratio in PVA/PVDF-based sensors compared with those made solely from PVA, highlighting a notable improvement in voice detection. The enhancements were quantified as 56% for “a”, 35% for “r”, and 47% for “m”.

The rapid growth of wearable devices for healthcare monitoring and portable consumer electronics has driven the demand for new sensors that are lightweight, flexible, and capable of real-time, continuous monitoring. Wearable sensors must conform to the human body and enable personalized, accessible health diagnostics beyond traditional point-of-care testing. The wearable sensor market is expected to grow significantly, from USD 1.6 billion in 2023 to USD 4.2 billion by 2028. Hydrogel-based wearable sensors, particularly those using polyvinyl alcohol (PVA), are promising candidates due to their flexibility, biocompatibility, hydrophilicity, and tunable electrochemical and mechanical properties. Triboelectric nanogenerators (TENGs) convert low-frequency mechanical energy into electrical energy by contact electrification between materials with different electronegativities. Hydrogel-based TENGs combine hydrogels’ mechanical and ionic properties with triboelectric effects to create self-powered, wearable sensors for monitoring human motion, pressure, and physiological signals. Surface roughness of PVA hydrogels significantly affects triboelectric sensor performance by increasing the contact area and enhancing charge generation, thus improving sensitivity and output. Optimizing surface roughness, hydrogel composition, and mechanical properties is crucial for developing high-performance wearable triboelectric sensors. In this study, PVA hydrogels with optimized surface roughness were fabricated using silicone rubber templates with varying porosity. The resulting single-electrode TENGs (S-TENGs) were tested as pressure sensors, with the best sensor achieving a sensitivity of 12.78 × 10⁻³ nC/Pa in the 20–160 Pa range. For wearable applications, safer hydrogels were developed by replacing sulfuric acid (H₂SO₄) with potassium chloride (KCl), making the devices more suitable for biomedical uses. A wearable sensor prototype based on this optimized PVA hydrogel demonstrated effective human motion detection, showcasing its potential for healthcare monitoring.