Search Results (213)

Bio-nanocomposites represent an advanced class of materials that combine the unique properties of nanomaterials with biopolymers, enhancing mechanical, electrical and thermal properties while ensuring biodegradability, biocompatibility and sustainability. These materials are gaining increasing attention, particularly in biomedical applications, due to their ability to interact with biological systems in ways that conventional materials cannot. Graphene and graphene oxide (GO), two of the most well-known nanocarbon-based materials, have garnered substantial interest in bio-nanocomposite research because of their extraordinary properties such as high surface area, excellent electrical conductivity, mechanical strength and biocompatibility. The integration of graphene-based nanomaterials within biopolymers, such as polysaccharides and proteins, forms a new class of bio-nanocomposites that can be tailored for a wide range of biological applications. This review explores the synthesis methods, properties and biotechnological applications of graphene-based bio-nanocomposites, with a particular focus on polysaccharide-based and protein-based composites. Emphasis is placed on the biotechnological potential of these materials, including drug delivery, tissue engineering, wound healing, antimicrobial activities and industrial food applications. Additionally, biodegradable polymers such as polylactic acid, hyaluronic acid and polyethylene glycol, which play a crucial role in biotechnological applications, will be discussed. Full article

In this study, gold nanoparticles (AuNPs) and AuNPs-graphene oxide (AuNPs@GO) nanostructures were synthesized in aqueous media using an in-situ photochemical method with bis-acyl phosphine oxide (BAPO) photoinitiator as a photoreducing agent in the presence of HAuCl₄. The parameters for synthesis were arranged to obtain stable and reproducible dispersions with desirable chemical and optical properties. Both AuNPs and AuNPs@GO were employed as sensing platforms for the detection of epinephrine in two concentration ranges: micromolar (µM) and nanomolar (nM). Field emission scanning electron microscopy (FE-SEM), Dynamic Light Scattering (DLS), UV-Vis absorption, fluorescence emission, and Fourier Transform Infrared (FT-IR) spectroscopy techniques were used to investigate the morphological, optical, and chemical properties of the nanostructures as well as their sensing ability towards epinephrine. Fluorescence spectroscopy played a crucial role in demonstrating the high sensitivity and effectiveness of these systems, especially in the low concentration (nM) range, confirming their strong potential as fluorescence-based sensors. By constructing calibration curves on best linear subranges, limit of detection (LOD) and limit of quantification (LOQ) were calculated with two different approaches, SE_intercept and S_y/x. Among all the investigated nanostructures, AuNPs@GO exhibited the highest sensitivity towards epinephrine. The efficiency and reproducibility of the in-situ photochemical AuNPs synthesis approach highlight its applicability in small-molecule detection and particularly in analytical and bio-sensing applications. Full article

Polyimine-based composites have emerged as a promising class of dynamic covalent thermosets, combining high mechanical strength, thermal stability, self-healing, recyclability, and reprocessability. This review systematically summarizes recent advances in polyimine synthesis, highlighting dynamic covalent chemistry (DCC) strategies such as imine exchange and reversible Schiff base reactions. Structural customization can be achieved by incorporating reinforcing phases such as carbon nanotubes, graphene, and bio-based fibers. Advanced fabrication methods—including solution casting, hot pressing, and interfacial polymerization—enable precise integration of these components while preserving structural integrity and adaptability. Mechanical performance analysis emphasizes the interplay between dynamic bonds, interfacial engineering, and multiscale design strategies. Polyimine composites exhibit outstanding performance characteristics, including a self-healing efficiency exceeding 90%, a tensile strength reaching 96.2 MPa, and remarkable chemical recyclability. Emerging engineering applications encompass sustainable green materials, flexible electronics, energy storage devices, and flame-retardant systems. Key challenges include balancing multifunctionality, enhancing large-scale processability, and developing low-energy recycling strategies. Future efforts should focus on interfacial optimization and network adaptivity to accelerate the industrial translation of polyimine composites, advancing next-generation sustainable materials. Full article

Printed electronics employ established printing methods to create low-cost, mechanically flexible devices including batteries, supercapacitors, sensors, antennas and RFID tags on plastic, paper and textile substrates. This review focuses on the specific contribution of screen printing to that landscape, examining how ink viscosity, mesh selection and squeegee dynamics govern film uniformity, pattern resolution and ultimately device performance. Recent progress in advanced ink systems is surveyed, highlighting carbon allotropes (graphene, carbon nano-onions, carbon nanotubes, graphite), silver and copper nanostructures, MXene and functional oxides that collectively enhance mechanical robustness, electrical conductivity and radio-frequency behavior. Parallel improvements in substrate engineering such as polyimide, PET, TPU, cellulose and elastomers demonstrate the technique’s capacity to accommodate complex geometries for wearable, medical and industrial applications while supporting environmentally responsible material choices such as water-borne binders and bio-based solvents. By mapping two decades of developments across energy-storage layers and functional electronics, the article identifies the key process elements, recurring challenges and emerging sustainable practices that will guide future optimization of screen-printing materials and protocols for high-performance, customizable and eco-friendly flexible devices. Full article

Heavy metal contamination in livestock and poultry farm wastewater poses significant risks to both the environment and human health, so it is critical to accurately and rapidly quantify heavy metal ion concentrations in water. This research develops a bioelectric active hydrogel sensor for detecting heavy metal ions in livestock wastewater. The sensor integrates microbial surface display technology with graphene hydrogel, displaying glucose oxidase (GOx) on the surface of yeast cells, and covalently incorporating it into the graphene hydrogel through the bio-reduction activity of metal-reducing bacteria, enhancing its electrochemical performance. The sensor demonstrates excellent sensitivity and stability in detecting Cu²⁺, with a detection limit for Cu²⁺ of 17.0 µM. This sensor is also applicable for detecting Zn²⁺ in wastewater. When various heavy metal ions coexist in the solution, they exert a more pronounced inhibitory effect on enzyme activity. Consequently, the sensor can be employed to assess the overall heavy metal content in water samples. In the detection of Cu²⁺ in real livestock and poultry wastewater, the recovery rate of the graphene hydrogel electrode ranged from 88% to 106.5%, indicating that the sensor holds significant potential for application in actual sample analysis. Full article

This work reports a study on the structural characterization, evaluation of thermal stability, and non-isothermal decomposition kinetics of urea–formaldehyde (UF) resin modified with hydrochar (obtained by the hydrothermal carbonization of spent mushroom substrate (SMS)) (UF-HC). The structural characterization of UF-HC, performed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction analyses, showed that UF-HC consists of a large number of spheroidal particles, which are joined, thus forming clusters. It constitutes agglomerates, which are composed of crystals that have curved plate-like forms, including crystalline UF structure and graphite lattices with an oxidized face (graphene oxide, GO). The measurement of inherent thermal stability and non-isothermal decomposition kinetic analysis was carried out using simultaneous thermogravimetric–differential thermal analyses (TGA-DTA) at various heating rates. Parameters that are obtained from thermal stability assessment have indicated the significant thermal stability of UF-HC. Substantial variation in activation energy and the pre-exponential factor with the advancement of decomposition process verifies the multi-step reaction pathway. The decomposition process takes place through three independent single-step reactions and one consecutive reactions step. The consecutive stage represents a path to the industrial production of valuable heterocyclic organic compounds (furan) and N-heterocyclic compounds (pyrroles), building a green-protocol trail. It was found that a high heating rate stimulates a high production of furan from cellulose degradation via the ring opening step, while a low heating rate favors the production of urea compounds (methylolurea hemiformal (HFn)) by means of methylene ether bridges breaking. Full article

To enhance the biocompatibility and drug delivery efficiency of graphene oxide (GO), poly(ethylene glycol) (PEG), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), or its triblock copolymer PEG-PHBV-PEG (PPP) were used to chemically modify GO. However, it is still unknown whether non-toxic polymer-modified GO mediates muscle toxicity or triggers intramuscular inflammation. This study aims to investigate the biological reactivity and inflammation/immune response induced by PEG, PHBV, or PPP modified GO when injected into the tibialis anterior (TA) muscle of mice prior to drug loading. The results showed that after muscle exposure, the coating of biocompatible polymers on GO is more likely to provoke muscle necrosis. Muscle regeneration was found to occur earlier and more effectively in muscle treated with hydrophilic PEG-GO and PPP-GO compared to muscle treated with hydrophobic PHBV-GO. When observing the transient muscle macrophage invasion of three modified GOs, PHBV-GO caused severe muscle necrosis in the early stage, induced a delayed peak of macrophage aggregation, and caused severe inflammatory progression. All three kinds of modified GO induced T cell aggregation to varying degrees, but PEG-GO induced early mass muscle recruitment of CD4⁺ T cells and was more sensitive to cytotoxic T cells. Based on the higher biocompatibility of PPP-GO in muscles, PPP-GO was implanted into the muscles of old or adult mice. Compared to adult mice, aged mice are more vulnerable to the stress from PPP-GO, as demonstrated by a delayed inflammatory response and muscle regeneration. Full article

The conversion of biochar, the low value byproduct of pyrolysis bio-oil production from biomass multi-walled carbon nanotubes (MWCNTs) and carbon nanochains (CNCs), is reported. It is shown that biomass can be converted to long (>30 µm) carbon nanotubes with an anomalously deep (>280 nm) stacked-cup structure. A mechanism of the transformation that is consistent with previously reported graphitization of biochar, a “non-graphitizable” carbon, is proposed, suggesting the molten metal catalyst is absorbed into the biochar by capillary action, forming graphene walls as it percolates through pore structure. Graphite is formed when the diameter of the molten catalyst droplets is large (microns), while smaller droplets (submicron) form MWCNTs and still smaller (<100 nm) form CNCs. Branching in the biochar pore structure leads to subdivision of the catalyst droplets resulting in the progression from MWCNT to CNC formation. Very long MWCNTs (>50 µm) can be formed in the absence of CNCs by transforming lignite char rather than biochar, presumably due to the elimination of smaller branching pores during coalification. CNCs, in the absence of MWCNTs, can be formed in biochar by using low concentrations of catalyst nanoparticles formed by carbon thermal reduction of a metal salt during charring. The results presented suggest that developing methods to control the porosity of the char could yield the ability to rationally synthesize carbon nanotubes with control of length, breadth and wall thickness. Full article

Active food packaging technology encompasses systems that incorporate active substances into the polymeric matrix. The embedded components exhibit antimicrobial, antifungal, and antioxidant properties and are able to absorb or reduce oxygen, carbon dioxide or ethylene, thereby enhancing the quality and safety of food products. The utilization of 2D nanomaterials, such as graphene, has facilitated the advent of novel avenues for the advancement of active packaging (AP). The integration of these materials with polymers has the potential to enhance the barrier, thermal, and mechanical properties of packaging materials. The objective of this paper is to provide a comprehensive overview of patented two-dimensional materials in the field of active packaging. Full article

The detection of glucose is crucial for diagnosing diseases such as diabetes and enables timely medical intervention. In this study, a disposable enzymatic screen-printed electrode electrochemical biosensor enhanced with machine learning (ML) for quantifying glucose in serum is presented. The platinum working surface was modified by chemical adsorption with biographene (BGr) and glucose oxidase, and the enzyme was encapsulated in polydopamine (PDP) by electropolymerisation. Electrochemical characterisation and morphological analysis (scanning and transmission electron microscopy) confirmed the modifications. Calibration curves in Cormay serum (CS) and selectivity tests with chronoamperometry were used to evaluate the biosensor’s performance. Non-linear ML regression algorithms for modelling glucose concentration and calibration parameters were tested to find the best-fit model for accurate predictions. The biosensor with BGr and enzyme encapsulation showed excellent performance with a linear range of 0.75–40 mM, a correlation of 0.988, and a detection limit of 0.078 mM. Of the algorithms tested, the decision tree accurately predicted calibration parameters and achieved a coefficient of determination above 0.9 for most metrics. Multilayer perceptron models effectively predicted glucose concentration with a coefficient of determination of 0.828, demonstrating the synergy of biosensor technology and ML for reliable glucose detection. Full article

Textile industry waste contains high concentrations of heavy metals such as Pb(II) and Cr(VI) that must be reduced before they are released to the environment. The adsorption method is one way to reduce the heavy metal content. In this work, we develop a porous cellulose nanofiber (CNF) aerogel modified with graphene oxide (GO) as an alternative aerogel adsorbent for Pb(II) and Cr(VI). Cellulose was extracted from banana peduncle, a biomass waste that remains largely underutilized. The addition of GO aims to increase the adsorption properties. The aerogel adsorbents were synthesized by varying the ultrasonication time to 45 min for CNF 45 and 60 min for CNF 60, and the amount of GO added to 1 mL and 2 mL. The aerogel adsorbents were successfully prepared using the freeze-drying method with CNF45, CNF60, CNF45/GO1, CNF45/GO2, CNF60/GO1, and CNF60/GO2 variations. CNF was successfully isolated from a banana peduncle with an average diameter of 44.16 nm for 45 min (CNF 45) and an average diameter of 14.6 nm for 60 min (CNF 60) of ultrasonication. Chemical treatment and ultrasonication reduced the crystallinity index value of cellulose by 73% and 61% for CNF 45 and CNF 60, respectively. CNF aerogel has a very low shrinkage rate (<7%), resulting in a larger surface area. CNF60/GO2 obtained the optimum adsorption ability for Pb(II) metal at a concentration of 100 ppm and 27.27 mg/g at 30 min. On the other hand, the adsorption ability of Cr(VI) metal was obtained by CNF60/GO2 at a concentration of 100 ppm and 13.48 mg/g at 30 min. SEM images show that all aerogel adsorbents are porous, with a porosity value range of 96–98%. In conclusion, CNF60/GO2 proved to be the most effective aerogel adsorbent, offering the potential for heavy metal removal from industrial wastewater. Full article

A cutting-edge biosensor has been developed to monitor blood glucose levels, which is particularly vital for people with diabetes. This advanced technology uses a miniaturized and membraneless enzymatic fuel cell (EFC) as a compact electrical reader for rapid on-site diabetes diagnosis. Using disposable screen-printed gold electrodes (Au-SPE) modified with the enzyme glucose oxidase (GOx), the biosensor enables the oxidation of glucose at both the anode (counter electrode) and cathode (working electrode) of the EFC. The cathode contains graphene oxide/Prussian blue nanocubes (GO/PBNCs), while the anode uses a biographene layer. Both electrodes were modified with GOx by electrostatic/hydrogen bonding the enzyme to the modified electrodes surface. Individual evaluations of each electrode system emphasized their effectiveness. The integration of both electrodes resulted in an EFC that can generate an output power of approximately 1.8 μW/cm² at a glucose concentration of 5 mmol/L, which is very close to physiological conditions (3.8 to 6.9 mmol/L). This technology represents a significant advance and promises fully autonomous diagnostic devices suitable for a wide range of analytes. It paves the way for diagnostics everywhere and marks a fundamental shift in point-of-care (PoC) diagnostics. Full article

Epoxy composites play a crucial role in modern materials technologies, with their exceptional properties such as high strength and thermal and chemical resistance, making them ideal for a wide range of industrial applications, including aerospace, automotive, construction, and energy. This review article provides a comprehensive overview of the current trends and advancements in epoxy composites, focusing on mechanical properties and their optimization. Attention is given to technological innovations, including the use of nanotechnologies, hybrid reinforcement, and eco-friendly materials, which are key to enhancing the performance and sustainability of these materials. The analysis shows that the introduction of nanomaterials, such as graphene, titanium dioxide, and silicon dioxide, can significantly improve the strength, fatigue resistance, and electrical properties of epoxy composites, opening new possibilities in advanced technologies. Another significant contribution is the development of hybrid composites, which combine different types of fibers, such as carbon, aramid, and glass fibers, enabling the optimization of key properties, including interlayer strength and delamination resistance. The article also highlights the importance of environmental innovations, such as bio-based resins and self-healing mechanisms, which enable more sustainable and long-term effective use of composites. The combination of theoretical knowledge with practical applications provides valuable guidance for designing materials with precisely defined properties for future industrial use. This text thus offers a comprehensive view of the possibilities of epoxy composites in the context of increasing demands for performance, reliability, and environmental sustainability. Full article

Objectives: To develop and evaluate graphene oxide/gelatin/alginate scaffolds for advanced wound therapy capable of mimicking the native extracellular matrix (ECM) and bio-stimulating all specific phases of the wound healing process, from inflammation and proliferation to the remodeling of damaged skin tissue in three dimensions. Methods: The scaffolds were engineered as interpenetrating polymeric networks by the crosslinking reaction of gelatin in the presence of alginate and characterized by structural, morphological, mechanical, swelling properties, porosity, adhesion to the skin tissue, wettability, and in vitro simultaneous release of the active agents. Biocompatibility of the scaffolds were evaluated in vitro by MTT test on fibroblasts (MRC5 cells) and in vivo using Caenorhabditis elegans assay. Results: The scaffolds exhibited a highly porous interconnected morphology with adjustable porosity (93–96%) and mechanical strength (1.10–2.90 MPa), hydrophilic nature with high capacity to absorb physiological fluids, and stable adhesion to the skin tissue. The obtained results of MRC5 cell viability indicate that the scaffolds are safe for biomedical applications. No mortality was detected among the Caenorhabditis elegans throughout the incubation period, indicating that the scaffolds are not toxic. The results of in vitro release study of allantoin, quercetin, and caffeic acid confirm the scaffolds’ significant potential for simultaneous release. Conclusion: The graphene oxide/gelatin/alginate scaffolds are promising candidates for non-invasive, dual ECM-mimetic, and multi-target wound therapy, offering an innovative strategy to address the complexities of wound healing process. Full article

In the growing field of personalized medicine, non-invasive wearable devices and sensors are valuable diagnostic tools for the real-time monitoring of physiological and biokinetic signals. Among all the possible multiple (bio)-entities, pH is important in defining health-related biological information, since its variations or alterations can be considered the cause or the effect of disease and disfunction within a biological system. In this work, an innovative (bio)-electrochemical flexible pH sensor was proposed by realizing three electrodes (working, reference, and counter) directly on a polyimide (Kapton) sheet through the implementation of CO₂ laser writing, which locally converts the polymeric sheet into a laser-induced graphene material (LIG electrodes), preserving inherent mechanical flexibility of Kapton. A uniform distribution of nanostructured PEDOT:PSS was deposited via ultrasonic spray coating onto an LIG working electrode as the active material for pH sensing. With a pH-sensitive PEDOT coating, this flexible sensor showed good sensitivity defined through a linear Nernstian slope of (75.6 ± 9.1) mV/pH, across a pH range from 1 to 7. We demonstrated the capability to use this flexible pH sensor during dynamic experiments, and thus concluded that this device was suitable to guarantee an immediate response and good repeatability by measuring the same OCP values in correspondence with the same pH applied. Full article