BACKGROUND: Nanozymes, a new class of nanomaterials, have emerged as promising substitutes for enzymes in biosensor design due to their exceptional stability, affordability, and ready availability. While nanozymes address many limitations of natural enzymes, they still face challenges, particularly in achieving the catalytic activity levels of their natural counterparts. This indicates the need for enhancing the sensitivity of biosensors based on nanozymes. The catalytic activity of nanozyme can be significantly improved by regulating its size, morphology, and surface composition of nanomaterial.
RESULTS: In this work, a kind of hollow core-shell structure was designed to enhance the catalytic activity of nanozymes. The hollow core-shell structure material consists of a nanozymes core layer, a hollow layer, and a MOF shell layer. Taking the classic peroxidase like Fe3O4 as an example, the development of a novel nanozyme@MOF, specifically p-Fe3O4@PDA@ZIF-67, is detailed, showcasing its application in enhancing the sensitivity of sensors based on Fe3O4 nanozymes. This innovative nanocomposite, featuring that MOF layer was designed to adsorb the signal molecules of the sensor to improve the utilization rate of reactive oxygen species generated by the nanozymes catalyzed reactions and the hollow layer was designed to prevent the active sites of nanozymes from being cover by the MOF layer. The manuscript emphasizes the nanocomposite\'s remarkable sensitivity in detecting hydrogen peroxide (H2O2), coupled with high specificity and reproducibility, even in complex environments like milk samples.
UNASSIGNED: This work firstly proposed and proved that Fe3O4 nanozyme@MOF with hollow layer structure was designed to improve the catalytic activity of the Fe3O4 nanozyme and the sensitivity of the sensors based on Fe3O4 nanozyme. This research marks a significant advancement in nanozyme technology, demonstrating the potential of structural innovation in creating high-performance, sensitive, and stable biosensors for various applications.

Nanoparticles are being used in novel applications of the thermoplastics industry, including automotive parts, the sports industry and leisure and consumer goods, which can be produced nowadays through additive manufacturing. However, there is limited information on the health and safety aspects during the production of these new materials, mainly from recycled sources. This study covers the exposure assessment to nano- and micro-size particles emitted from the nanocomposites during the production of filaments for 3D printing through a compounding and extrusion pilot line using recycled (post-industrial) thermoplastic polyurethane (TPU) and recycled polyamide 12 (PA12), which have been also upcycled through reinforcement with iron oxide nanoparticles (Fe3O4 NPs), introducing matrix healing properties triggered by induction heating. The assessment protocol included near- and far-field measurements, considering the extruder as the primary emission source, and portable measuring devices for evaluating particulate emissions reaching the inhalable zone of the lab workers. A Failure Modes and Effects Analysis (FMEA) study for the extrusion process line was defined along with a Failure Tree Analysis (FTA) process in which the process deviations, their sources and the relations between them were documented. FTA allowed the identification of events that should take place in parallel (simultaneously) or in series for the failure modes to take place and the respective corrective actions to be proposed (additional to the existing control measures).

The antimicrobial properties of two-dimensional materials such as graphene-based surfaces are vital for environmental and biomedical applications. Here, the improvement of the antibacterial property of reduced graphene oxide by the preparation of rGO-CuO nanocomposite films was reported. The rGO-CuO nanocomposites were synthesized via a simple hydrothermal method, and the nanocomposite films were fabricated by filtering through a polytetrafluoroethylene (PTFE) filter with the assistance of a vacuum filtration unit. After characterization of the nanocomposite films, the antibacterial properties were tested against Pseudomonas aeruginosa PAO1. The fabricated rGO-CuO nanocomposite films exhibited excellent antibacterial activity, leading to complete bacterial inactivation upon contact. The antibacterial properties were closely linked to the reactive oxygen species (ROS) independent pathway rather than the ROS-dependent pathway. This work provides an insight into the antibacterial mechanisms of reduced GO and copper oxide composite film for water treatment systems and the potential application of these nanocomposites in biomedicine.

Lutetium vanadate (LuVO4) is a promising material for electrochemical application owing to its good conductivity and electrocatalytic activity. Herein, we demonstrate a facile technique for the synthesis of a LuVO4/ graphene sheet (GRS) nanocomposite where LuVO4 is encapsulated with an ultrathin GRS to form a hierarchical structure (LuVO4/GRS). The resulting hierarchical LuVO4/GRS architecture was characterized by several analytical and spectroscopic techniques. The resultant electrocatalyst shows superior electrochemical sensing for nitrofurantoin (NFT) with a low detection limit (0.001 μM), wide linear range (0.008-256.0 μM) and excellent sensitivity (1.709 μA μM-1 cm-2). It has been demonstrated that the enhanced electrocatalytic performance of LuVO4/GRS nanocomposite is due to their excellent electrical conductivity, suitable surface area, high redox reaction and large number of electron transport. In addition, the LuVO4/GRS nanocomposite exhibited excellent response towards NFT detection with adequate reproducibility, good repeatability, long-term stability and excellent selectivity over its structural analogs and common interferents. Furthermore, the practical applicability of the proposed electrochemical sensor was successfully applied for determination of NFT in environmental samples with satisfactory results. The LuVO4/GRS nanocomposite presented here can serve as a favorable candidate for developing electrochemical sensor and plays an important role in widespread fields.

Polyesters made from 2,5-furandicarboxylic acid (FDCA) have been in the spotlight due to their renewable origins, together with the promising thermal, mechanical, and/or barrier properties. Following the same trend, (nano)composite materials based on FDCA could also generate similar interest, especially because novel materials with enhanced or refined properties could be obtained. This paper presents a case study on the use of furanoate-based polyesters and bacterial cellulose to prepare nanocomposites, namely acetylated bacterial cellulose/poly(butylene 2,5-furandicarboxylate) and acetylated bacterial cellulose/poly(butylene 2,5-furandicarboxylate)-co-(butylene diglycolate)s. The balance between flexibility, prompted by the furanoate-diglycolate polymeric matrix; and the high strength prompted by the bacterial cellulose fibres, enabled the preparation of a wide range of new nanocomposite materials. The new nanocomposites had a glass transition between -25⁻46 °C and a melting temperature of 61⁻174 °C; and they were thermally stable up to 239⁻324 °C. Furthermore, these materials were highly reinforced materials with an enhanced Young\'s modulus (up to 1239 MPa) compared to their neat copolyester counterparts. This was associated with both the reinforcing action of the cellulose fibres and the degree of crystallinity of the nanocomposites. In terms of elongation at break, the nanocomposites prepared from copolyesters with higher amounts of diglycolate moieties displayed higher elongations due to the soft nature of these segments.

Ball Milling technique has been used to prepare for the first time Vitis Vinifera extract-silica nanocomposites (VV-SiO2 NCs), which combine the pharmacological effects of the extract with the effectiveness of silica as drug delivery system and active component in the treatment of wound healing. Different contents (1.0, 9.0 and 33.0 wt%) of Vitis Vinifera ethanolic extract were loaded into the silica matrix by grinding the extract with fumed silica using a planetary mill apparatus. The effect of the starting mixture composition and milling time on the final products was examined. The efficiency of the milling process was studied by X-ray Powder Diffraction, Nuclear Magnetic Resonance, and Infrared Spectroscopy, indicating that the natural extract was not affected by the increasing of the milling time. The successful loading of the extract was demonstrated by Nitrogen adsorption/desorption measurements, which showed a decrease in the SSA and pore volume of the silica with the increasing of the extract amount. Morphology of the nanocomposites, investigated by Scanning Electron Microscopy, showed an increased agglomeration in the nanocomposites with the increment of the VV extract amount. Studies on the total phenol quantification and antioxidant activity of the natural extract before and after incorporation in the silica matrix were also carried out. The obtained results indicate that the milling process does not alter the VV extract components, which result to be embedded in the silica matrix. An increase of the antioxidant activity with the increment of the extract amount in the nanocomposites, up to values comparable to the pure VV extract, was also observed.

The aim of this communication is to synthesize novel Nanocomposite thin film materials (Ag0(NP)/TiO2) using the template process. Surface morphology of materials was obtained by the Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses. The presence of doped Ag-nanoparticles was confirmed by the TEM images along with the SEM-EDX analyses. The Atomic Force Microscopic images were demonstrated the surface roughness and thickness of Nanocomposite thin films. X-ray diffraction analysis confirmed that TiO2 was predominantly present to its anatase mineral phase. The Fourier Transform Infra-red analysis conducted to obtain the functional groups present with the solid. The specific surface area and pore sizes of Nanocomposites were obtained by the BET (Brunauer, Emmett, and Teller) analysis. Further, the Nanocomposite thin film photocatalysts were successfully employed in the degradation of emerging micro-pollutants viz., the antibiotics tetracycline and sulfamethoxazole from aqueous solutions using less harmful UV-A light (λmax 330 nm). The effect of solution pH (pH 4.0-8.0) and pollutant concentrations (1.0 mg/L-20.0 mg/L (for tetracycline) and (0.5 mg/L-15.0 mg/L (for sulfamethoxazole)) was extensively studied in the photocatalytic removal of these antibiotics. A significant decrease in percentage of non-purgeable organic carbon removal indicated that the micro-pollutants was substantially mineralized by the photocatalytic treatment. The stability of thin film was assessed by the repeated use of Nanocomposite thin films and results were indicated that the degradation of tetracycline or sulfamethoxazole was almost unaffected at least for six cycles of photocatalytic operations. The presence of several cations and anions in the degradation of these antibiotics was studied. Additionally, the presence of 2-propanol and EDTA inhibited significantly the degradation of these micro-pollutants i.e., the percentage of degradation was decreased by 31.8 and 24.2% (for tetracycline) and 42.8 and 39.9% (for sulfamethoxazole), respectively. This indicated that the degradation of tetracycline or sulfamethoxazole was predominantly proceeded by the OH radicals; generated at the valance and conduction band of semiconductor. Similarly, the presence of sodium azide inhibited the percentage removal of these antibiotics.

Background. Use of hearing protection devices has become necessary when other control measures cannot reduce noise to a safe and standard level. In most countries, more effective hearing protection devices are in demand. Objective. The aim of this study was to examine the effects of titanium dioxide (TiO2) nanoparticles on noise reduction efficiency in a polyvinyl chloride (PVC) earplug. Methods. An S-60 type PVC polymer as the main matrix and TiO2 of 30-nm size were used. The PVC/TiO2 nanocomposite was mixed at a temperature of 160 °C and 40 rpm and the samples were prepared with 0, 0.2 and 0.5 wt% of TiO2 nanoparticle concentrations. Results. Earplug samples with PVC/TiO2 (0.2, 0.5 wt%) nanoparticles, when compared with raw earplugs, showed almost equal noise attenuation at low frequencies (500-125 Hz). However, at high frequencies (2-8 kHz), the power of noise reduction for earplugs containing TiO2 nanoparticles was significantly increased. Conclusions. The results of the present study showed that samples containing nanoparticles of TiO2 had more noticeable noise reduction abilities at higher frequencies in comparison with samples without the nanoparticles.

The purpose of this study is to analyze the mechanical enhancement provided by nanocomposite coatings deposited on robocast 45S5 bioglass (BG) scaffolds for bone tissue regeneration. In particular, a nanocomposite layer consisting of hydroxyapatite (HA) nanoparticles, as reinforcing phase, in a polycaprolactone (PCL) matrix was deposited onto the surface of the BG struts conforming the scaffold. Three different HA nanopowders were used in this study. The effect of particle size and morphology of these HA nanopowders on the mechanical performance of 45S5 BG scaffolds is evaluated.