Morphed graphene (MG) has only recently been put forward as the perfect reinforcement composite material for structure composites due to its unique mechanical properties. This article addresses the possibility of applying MG as a toughener phase in composites of cement for oil-well. MG was synthesized from petroleum coke through control milling and incorporated into cement with varying concentrations (0.1-1 %). The mechanical behavior of MG-reinforced cement demonstrated significant improvements, including enhanced fracture energy, flexural strength, and compression strength. Electron microscopy morphological analysis confirmed that MG effectively reduced porosity and improved particle cohesion.

Metal-based drugs are of capital relevance for the modern medical chemistry. Nonetheless, their use has faced several issues related to toxicity and scarce biocompatibility. Metal-doped carbon dots can represent an interesting and promising solution for simultaneously exploiting the properties of metal-based drugs together with the superior biocompatibility, solubility, and photoluminescent properties of pristine carbon dots. In this concise review, we discussed the utilization of metal-doped carbon dots in biomedical applications with a focus on chemotherapy and diagnostic uses.

In this study, we explored the effect of Cr3+ substitution by partially and fully replacing Fe3+ in the normal spinel ZnFe2O4 crystal structure at electrochemical interfaces. The resulting ZnCrxFe2-xO4 nanomaterials exhibited an average particle size between 20 and 50 nm with a spherical morphology. The materials also demonstrated energy band gaps ranging from 2.1 to 3.1 eV X-ray diffraction (XRD) analysis confirmed that all the synthesized materials maintained a normal spinel structure, attributed to the octahedral site preference energy (OSPE) of Zn2+, Fe3+, and Cr3+ ions. Electrochemical performance assessments revealed that the ZnFe2O4-based sensor achieved a sensitivity of (37.8 f 0.2) mu A/mM with a kinetic rate constant of (13.1 f 2.8) ms-1, while the ZnCr2O4-based sensor exhibited a sensitivity of (32.4 f 0.5) mu A/mM and a kinetic rate constant of (3.73 f 0.55) ms-1 in the detection of paracetamol, whereas ZnCrFeO4 sensor has produced the second-best sensitivity (35.7 f 0.1 mu A/mM) and the rate constant (4.53 f 0.54 ms-1) with the lowest limit of detection (1.94 f 0.01 mu M). These differences in electrochemical performance were correlated with the variations in the energy band gaps caused by the restructuring of the normal spinel structure. Our findings indicate that the ZnFe2O4 sensor has a higher potential for direct electron transfer, whereas the other sensors are more likely to facilitate surface-mediated electron transfer.

The detection of dopamine represents an intriguing and relevant field of application for electrochemical sensors. The sensors tailored with inorganic species are of great interest due to their high tuneability in both morphology and chemical features. In this work, we investigate the effect of different amounts of poly(ethylene glycol) used as template agent for ultrasound assisted synthesis of bismuth oxynitrates on composition and morphology. We found that the increase in poly(ethylene glycol) induced a surface defectiveness on bismuth oxynitrate boosting electrochemical sensing performances reaching sensitivity of up to 16 μA/mM and LOD close to 2 μM and achieving a sixfold increase in the electron transfer rate compared with the bare electrode.

This work presents the application of zinc oxide (ZnO) and zinc ferrite (ZnFe2O4) for electrochemical pH sensing. ZnO and ZnFe2O4 are synthesized by auto-combustion synthesis method. Field emission scanning electron microroscopic (FESEM) images revealed that ZnO particles have pyramid- and spherical-shaped morphology with micrometer dimensions, while ZnFe2O4 particles have spherical shape at the nanoscale. The surface-modified screen-printed electrodes with ZnO and ZnFe2O4 particles are initially characterized by the ferri/ferrocyanide redox couple. Significant improvement in sensitivity (bare carbon: 6.3 +/- 0.4 mu A/mM, ZnO: 8.5 +/- 0.3 mu A/mM, ZnFe2O4: 8.9 +/- 0.5 mu A/mM) and rate constant (bare carbon: 10 +/- 1 ms(-1) , ZnO: 46 +/- 4 ms(-1) , ZnFe2O4: 42 +/- 3 ms(-1 )) is observed with the surface-modified sensors. Chronopotentiometric pH response of the sensors showed hysteresis behavior with pH loop. No interference effects are observed, and the pH sensitivity of the bare carbon sensor ( 23.9 +/- 1.4 mV/pH) is increased by the introduction of ZnO ( 38.1 +/- 1.3 mV/pH) and ZnFe2O4 ( 37.2 +/- 1.1 mV/pH) particles. Stability of the pH response is discussed, and ways for its improvement are proposed.

Nanostructured metal oxides with spinel crystalline structures are highly attractive for electrochemical sensing due to their ability to enhance the catalytic activity of redox processes, improving sensitivity and lowering limits of detection. At the same time, cytochrome P450 enzymes (P450s) confer substrate specificity, enabling the selective detection of therapeutic compounds. This study investigates the integration of spinel-structured metal oxide nanoparticles—ZnCr _2 O _4 , ZnFe _2 O _4 , and CuFe _2 O _4 —with cytochrome P450 enzymes to enable the selective electrochemical detection of cyclophosphamide, a widely used anticancer drug metabolized by these enzymes. Screen-printed carbon electrodes were functionalized with these spinel oxides and two P450 isoforms: CYP3A4 and CYP2B6. Spinel oxide-modified electrodes showed enhanced catalytic activity, with further sensitivity improvements when combined with P450 enzymes. The ZnCr _2 O _4 /CYP2B6 configuration achieved the highest sensitivity of 6.9 nA/ M, while ZnFe _2 O _4 /CYP3A4 improved the limit of detection nearly twentyfold. These findings highlight the synergistic benefits of enzyme-nanoparticle coupling, demonstrating the potential of spinel oxides and P450 enzymes for developing sensitive, selective electrochemical biosensors for drug monitoring.

This research addresses a gap in the literature by exploring the combined use of hemp and hemp hurds in composites, presenting a novel approach to bio-composite development. We report on the mechanical properties of epoxy resin composites reinforced with hemp fibers and hemp hurds, selected for their sustainability, biodegradability, and environmental benefits. These natural fibers offer a renewable alternative to synthetic fibers, aligning with the growing demand for eco-friendly materials in various industries. The primary objective was to evaluate how different filler contents and hemp hurd-to-hemp fiber ratios affect the composite’s performance. Composites with 1:1 and 3:1 ratios were prepared at filler concentrations ranging from 1 wt.% to 10 wt.%. Tensile tests revealed that the 3:1 ratio composites exhibited better stiffness and tensile strength, with a notable UTS of 19.8 ± 0.4 MPa at 10 wt.%, which represents a 160% increase over neat epoxy. The 1:1 ratio composites showed significant reductions in mechanical properties at higher filler contents due to filler agglomeration. The study concludes that a 3:1 hemp hurd-to-hemp fiber ratio optimizes mechanical properties, offering a sustainable solution for enhancing composite materials’ performance in industrial applications.

The appeal of carbon dots (CDs) has grown recently, due to their established biocompatibility, adjustable photoluminescence properties, and excellent water solubility. For the first time in the literature, copper chlorophyllin-based carbon dots (Chl-D CDs) are successfully synthesized. Chl-D CDs exhibit unique spectroscopic traits and are found to induce a Fenton-like reaction, augmenting photodynamic therapy (PDT) efficacies via ferroptotic and apoptotic pathways. To bolster the therapeutic impact of Chl-D CDs, a widely used cancer drug, temozolomide, is linked to their surface, yielding a synergistic effect with PDT and chemotherapy. Chl-D CDs' biocompatibility in immune cells and in vivo models showed great clinical potential.Proteomic analysis was conducted to understand Chl-D CDs' underlying cancer treatment mechanism. The study underscores the role of reactive oxygen species formation and pointed toward various oxidative stress modulators like aldolase A (ALDOA), aldolase C (ALDOC), aldehyde dehydrogenase 1B1 (ALDH1B1), transaldolase 1 (TALDO1), and transketolase (TKT), offering a deeper understanding of the Chl-D CDs' anticancer activity. Notably, the Chl-D CDs' capacity to trigger a Fenton-like reaction leads to enhanced PDT efficiencies through ferroptotic and apoptotic pathways. Hence, it is firmly believed that the inherent attributes of Chl-CDs can lead to a secure and efficient combined cancer therapy. In a groundbreaking development, copper chlorophyllin-based carbon dots (Chl-D CDs) are synthesized, displaying unique red emissive traits, and enhancing photodynamic therapy (PDT) by harnessing Fenton-like reaction. Chl-D CDs' ability to enhance PDT through ferroptotic and apoptotic pathways offers a secure and efficient approach to combined cancer therapy, making them an intriguing topic for exploration.image

The interaction between matter and microwaves assumes critical significance due to the ubiquity of wireless communication technology. The selective shielding of microwaves represents the only way to achieve the control on crucial technological sectors. The implementation of microwave shielding ensures the proper functioning of electronic devices. By preventing electromagnetic pollution, shielding safeguards the integrity and optimal performances of devices, contributing to the reliability and efficiency of technological systems in various sectors and allowing the further step forwards in a safe and secure society. Nevertheless, the microwave shielding research is vast and can be quite hard to approach due to the large number and variety of studies regarding both theory and experiments. In this review, we focused our attention on the comprehensive discussion of the current state of the art of materials used for the production of electromagnetic interference shielding composites, with the aim of providing a solid reference point to explore this research field.

The development of new and high-performing electrode materials for sensing applications is one of the most intriguing and challenging research fields. There are several ways to approach this matter, but the use of nanostructured surfaces is among the most promising and highest performing. Graphene and graphene-related materials have contributed to spreading nanoscience across several fields in which the combination of morphological and electronic properties exploit their outstanding electrochemical properties. In this review, we discuss the use of graphene and graphene-like materials to produce gas sensors, highlighting the most relevant and new advancements in the field, with a particular focus on the interaction between the gases and the materials.

The production of multipurpose sustainable fillers is a matter of great interest, and biochar can play a pivotal role. Biochar is a biomass-derived carbon source that can act as a versatile platform for the engineering of fillers as neat or functionalized materials. In this work, we investigate the utilization of 800 °C annealed Miscanthus-derived biochar as a filler for the production of epoxy composites with promising mechanical and electrical properties. We also used it in the production of an iron-rich hybrid filler in order to fine-tune the surface and bulk properties. Our main findings reveal that hybrid composites containing 20 wt.% biochar exhibit a 27% increase in Young’s modulus (YM), reaching 1.4 ± 0.1 GPa, while the ultimate tensile strength (UTS) peaks at 30.3 ± 1.8 Mpa with 10 wt.% filler, a 27% improvement over pure epoxy. However, higher filler loadings (20 wt.%) result in decreased UTS and maximum elongation. The optimal toughness of 0.58 ± 0.14 MJ/m³ is observed at 5 wt.% filler content. For organic composites, YM sees a notable increase of 90%, reaching 2.1 ± 0.1 Gpa at 20 wt.%, and UTS improves by 32% with the same filler content. Flexural tests indicate an enhanced elastic modulus but reduced maximum elongation as filler content rises. Electromagnetic evaluations show that hybrid fillers maintain a primarily dielectric behavior with a negligible impact on permittivity, while biochar–epoxy composites exhibit increased conductivity at higher filler loadings, suitable for high-frequency applications. In light of these results, biochar-based fillers demonstrate significant potential for enhancing the mechanical and electrical properties of epoxy composites.

The interfaces between medical implants and living tissues are of great complexity because of the simultaneous occurrence of a wide variety of phenomena. The engineering of implant surfaces represents a crucial challenge in material science, but the further improvement of implant properties remains a critical task. It can be achieved through several processes. Among them, the production of specialized coatings based on carbon-based materials stands very promising. The use of carbon coatings allows one to simultaneously fine-tune tribological, mechanical, and chemical properties. Here, we review applications of nanostructured carbon coatings (nanodiamonds, carbon nanotubes, and graphene-related materials) for the improvement of the overall properties of medical implants. We are focusing on biological interactions, improved corrosion resistance, and overall mechanical properties, trying to provide a complete overview within the field.

This work investigates the effect of the inclusion of Bi3+ ions in ZnFe2O4 nanoparticles on electron transfer at the electrochemical interface. ZnBixFe2-xO4 (x = 0, 0.5, 1, 2) nanomaterials are synthesized and the impact of Bi3+ ions on the chemical features of ZnFe2O4 nanoparticles is studied by using different materials' characterization techniques. The effect of the change in the chemical composition of ZnFe2O4 nanoparticles on the electrochemical sensing performance is extensively studied and correlated with the electrochemical sensitivity and kinetic rate constant. Screen-printed electrodes functionalized with ZnBixFe2-xO4 nanomaterials have an excellent enhancement of electrochemical sensing performance towards paracetamol, as a test molecule, compared to the carbon electrodes. The highest sensitivity (37.8 f 0.2 mu A/mM) and the best kinetic rate constant (13.1 f 2.8 ms-1) are achieved by the ZnFe2O4 sensor, while the ZnBi2O4 sensor achieved a sensitivity of (23.5 f 0.6) mu A/ mM with a kinetic rate constant of (0.45 f 0.16) ms- 1. The ZnFe2O4 sensor is found to have a direct electron transfer, whereas the other sensors participate in a surface state-mediated electron transfer at the electrochemical interface. This research shows a clear path to the potential applications of spinel oxide-based electrochemical sensors for specific drugs or molecules detection.

Spinel metal oxides possess excellent magnetic, electrical, and optical properties. They take AB 2 O 4 (face centered cubic) form with oxygen anions providing tetrahedral (Td) and octahedral (Oh) sites for A +2 and B +3 cations. Spinel can have a normal, inverse, or mixed form based on the occupancy of different cations in Td and Oh sites. The peculiarity of the spinel crystal structure is that its composition can be easily modified without affecting the crystal structure based on the type of cation. The type of cation in the composition defines if the spinel has a normal or inverse form [1]. Based on these premises, we have already synthesized Zn x Ni 1-x Fe 2 O 4 (x =0, 0.2, 0.4, 0.6, 0.8, 1) nanomaterials achieving a clear gradual transition from inverse (x=0) to normal (x=1) spinel. Synthesized nanomaterials were employed as mediators in electron transfer between the screen-printed carbon working electrode and paracetamol to understand the effect of chemical composition and crystal structure on the electron transfer at the electrochemical interface [1]. Normal spinel ZnFe 2 O 4 was found to be the best nanomaterial in terms of sensitivity and kinetic rate constant. In further works, with the aim to understand the effect of ionic radii on sensitivity and electron transfer rate constant in electrochemical sensing of paracetamol, we have focused on the normal spinel structure and modified the composition by varying the concentration of Fe 3+ with Cr 3+ and Bi 3+ [2,3]. This study also proved that the normal spinel ZnFe 2 O 4 has the highest sensitivity and electron transfer rate constant towards paracetamol sensing. In this work, we will present the synergic effect that can be obtained by interfacing ZnFe 2 O 4 with ZnO nanomaterials by tuning the band gap of the heterogeneous structure. The aim is to understand the effect of band gap on sensitivity and electron transfer rate constant in electrochemical sensing. ZnFe 2 O 4 , ZnO, and ZnO/ZnFe 2 O 4 nanomaterials are synthesized by a simple, single step auto combustion technique using the respective metal nitrates as precursors. Nanomaterial morphology and particles size are investigated by scanning electron microscopy. X-ray diffraction technique is employed to analyze the crystal structure and identify different phases in the newly synthesized materials. Then, commercially available screen-printed carbon electrodes with carbon working electrode and carbon counter electrodes are used for the electrochemical measurements in combination with an external double junction Ag/AgCl as a reference electrode. The synthesized nanomaterials are mixed with 1-butanol and a 5 μL solution is used to modify the surface of the carbon working electrode to mediate the redox reactions between the carbon surface and the molecule of interest. Primarily the sensors are characterized using cyclic voltammetry with ferri/ferrocyanide redox couple as a probe molecule. Improvement in sensitivity is observed for ZnFe 2 O 4 (8.85 ± 0.50 μA/mM), ZnO (8.50 ± 0.30 μA/mM), and ZnO/ZnFe 2 O 4 (8.22 ± 0.16 μA/mM) sensors compared to the bare carbon one (6.30 ± 0.40 μA/mM). By performing cyclic voltammetry at different scan rates (ν) from 25 to 125 mV/s, a good linearity of redox currents with respect to v 0.5 is observed and redox peak positions are varying linearly with ln(ν). Peak-to-peak separation (ΔE p ) is reduced for ZnO/ZnFe 2 O 4 sensors compared to the carbon one. All these results suggest a faster electron transfer at the interface when the modified electrodes are used. Laviron model is employed to calculate the electron transfer rate coefficient and constant. The rate constant for ZnFe 2 O 4 (41.8 ± 2.6 ms -1 ), ZnO (46.0 ± 4.0 ms -1 ), and ZnO/ZnFe 2 O 4 (33.1 ± 4.5 ms -1 ) sensors is 3 to 5 times higher as compared to the bare carbon one (9.97 ± 0.78 ms -1 ). We are currently studying the potential application of ZnO/ZnFe 2 O 4 nanomaterials in electrochemical sensing of small molecules relevant in biomedical field (dissolved oxygen, pH) and pharmaceutical drugs (paracetamol) to assess the potential for their use in different clinical settings. References: M.Madagalam et al., “Unraveling the effect of chemical and structural composition of Zn x Ni 1-x Fe 2 O 4 on the electron transfer at the electrochemical interface,” Small Struct . 2023, 2300163. M.Madagalam et al., “ZnM x Fe 2-x O 4 (M=Cr, Bi) Nanoparticles-modified electrochemical sensors: Effect on sensitivity and first-order kinetic rate constant,” 2023 IEEE BioSensors Conference (BioSensors) , London, United Kingdom, 2023, pp. 1-4, doi: 10.1109/BioSensors58001.2023.10280910. M. Madagalam et al., "ZnCr2-xFexO4 Nanoparticles-Modified Electrochemical Sensors: A Comparative Study," 2023 IEEE SENSORS , Vienna, Austria, 2023, pp. 01-04, doi: 10.1109/SENSORS56945.2023.10325135. Figure 1

In recent years, the utilisation of oxygen-deficient zirconia (ZrO2-α), commonly referred to as black zirconia, has garnered considerable attention due to its potential applications for solid oxide fuel cells (SOFCs), gas sensors, biomedical implant materials, and photocatalysis. However, current methods employed to manufacture ZrO2-α exhibit noticeable limitations regarding their scalability, environmental sustainability, and cost-effectiveness. Our recent work has successfully demonstrated the feasibility for bulk conversion of conventional white zirconia into oxygen-deficient black zirconia through direct current (DC) plasma treatment (i.e. plasma blackening). This study elucidates the conditions for plasma blackening and provides a unique mechanism for the bulk transformation of zirconia. A systematic investigation of different plasma technologies (DC, active-screen plasma), treatment configurations (contact conditions, cathode material, and cathode potential), and treatment parameters (voltage, temperature, duration) uncover the crucial variables that influence the feasibility and rate of the reduction process. The reduction of zirconia is shown to initiate from localised contacting points at the cathode-facing surface and grow, with a hemispherical shape, towards the anode-facing surface. A series of development stages are proposed for the process, namely: bulk oxygen vacancy conductance, surface activation, oxygen vacancy generation and a moving cathode front. The findings of this study provide insights into the underlying mechanisms involved in the bulk-reduction of zirconia and help to pave the way towards future scalable and cost-effective generation of oxygen-deficient zirconia.

While the World Health Organization has declared the end of the SARS-CoV-2 public health emergency, studies related to corona viruses are still under course. As of 2024, the severity of COVID-19 has diminished with current treatments and vaccinations. However, individuals can still face severe complications, highlighting the importance of ongoing research into innovative treatments for current and future coronavirus-related diseases. This study approaches the mechanism of viral entrance into the host cells and the current evidence on the use of sulfhydryl groups for the COVID-19 treatment. Certain thiol drugs, a key contributor to inflammatory processes, exhibit both viral inhibition properties and the potential to regulate cellular oxidative stress by scavenging free radicals. Herein, we developed biocompatible thiol-functionalized carbon dots (CDs) and investigated the correlation between the number of thiols and pseudo-SARS-CoV-2 inhibition, reactive oxygen species (ROS) scavenging, and anti-inflammatory response. The free-radical scavenging experiment and the ROS cellular assay indicate that thiolated CDs serve as effective reducing agents and potential regulators of cellular oxidative stress. The CDs also demonstrated good cell viability alongside significant antiviral capabilities, with inhibition levels up to 60.4%. Furthermore, the flow cytometry results suggest that in an inflammatory environment, the presence of thiolated CDs promotes an anti-inflammatory response. Overall, the results demonstrate a strong correlation between the number of thiols and the increased efficacy observed across experiments, presenting thiolated CDs as promising candidates to prevent and treat COVID-19 infection.

While biochar is an effective and viable tool for alleviating climate change, monolithic biochar is emerging as a functional material for applications that enhance sustainability, such as renewable energy storage and low-cost, high-efficiency water purification. Its performance depends on its physical and chemical characteristics, including electrical conductivity. Monolithic biochar's bulk conductivity is expected to rely on the porosity and conductivity of its carbon matrix - intrinsic conductivity - a fundamental property that has not been systematically studied. The work discerns intrinsic conductivity and its dependence on biomass species and carbonization temperature. We carbonized four hardwoods, three softwoods, and bamboo following an ultra-slow pyrolysis procedure and characterized biochar's chemical and structural properties. We modified the two-probe method and measured bulk conductivity along the axial direction. The bulk conductivity and density followed the linear and the Reynolds-Hough relationships, allowing the determination of intrinsic conductivity. The intrinsic conductivity increased with pyrolysis temperatures and became independent of wood species at 1500 degrees C. According to the linear model, the highest value of wood biochar produced at 1500 degrees C was 14,600 S/m. Bamboo biochar had a higher intrinsic conductivity (21,000 S/m), attributed to bamboo's high cellulose content and large graphite nanocrystal size in its biochar. Moreover, the modified two-probe method minimized measurement uncertainty and enabled the quantification of natural variation in biochar conductivity, which was less than 10% for the same wood species. These findings will help strengthen monolithic biochar's potential as a lowcost, high-performance functional material.

Carbon nanotubes (CNTs) have attracted significant attention in the scientific community and in the industrial environment due to their unique structure and remarkable properties, including mechanical strength, thermal stability, electrical conductivity, and chemical inertness. Despite their potential, large-scale applications have been limited by challenges such as high production costs and catalyst contamination. In aerospace applications, CNTs have demonstrated considerable promise either in the form of thin layers or as reinforcements in polymer and metal matrices, where they enhance mechanical, thermal, and electromagnetic performance in lightweight composites. In this short review, we provide an overview of CNTs’ properties and structures, explore CNT growth methods, with a focus on chemical vapor deposition (CVD), and examine their integration into aerospace materials both as films and as multifunctional reinforcements.

The recycling of Carbon Fibre-Reinforced Polymers (CFRPs) is becoming increasingly crucial due to the growing demand for sustainability in high-performance industries such as automotive and aerospace. This study investigates the impact of two chemical recycling techniques, chemically assisted solvolysis and plasma-enhanced solvolysis, on the morphology and properties of carbon fibres (CFs) recovered from end-of-life automotive parts. In addition, the effects of fibre sizing are explored to enhance the performance of the recycled carbon fibres (rCFs). The surface morphology of the fibres was characterised using Scanning Electron Microscopy (SEM), and their structural integrity was assessed through Thermogravimetric Analysis (TGA) and Raman spectroscopy. An automatic analysis method based on optical microscopy images was also developed to quantify filament loss during the recycling process. Mechanical testing of single fibres and yarns showed that although rCFs from both recycling methods exhibited a ~20% reduction in tensile strength compared to reference fibres, the application of sizing significantly mitigated these effects (~10% reduction). X-ray Photoelectron Spectroscopy (XPS) further confirmed the introduction of functional oxygen-containing groups on the fibre surface, which improved fibre-matrix adhesion. Overall, the results demonstrate that plasma-enhanced solvolysis was more effective at fully decomposing the resin, while the subsequent application of sizing enhanced the mechanical performance of rCFs, restoring their properties closer to those of virgin fibres.

In this new study, we present an intriguing development in the field of theranostics: the simplistic self-assembly of red-emissive amphiphilic porphyrin-like carbon dots (P-CDs). By harnessing their exceptional photophysical properties, we have revealed a strong candidate as the ideal photosensitizer (PS) for applications, particularly in the realm of imaging. Spanning a remarkable size average between 1-4 nm, these particles exhibit both highly stable and unparalleled emission characteristics between 650 and 715 nm in water in comparison to current carbon dots (CDs) available. Lastly, these CDs were fairly non-toxic when tested against normal human cell lines as well as were found to have favorable imaging capabilities in zebrafish embryo.