El Shazly M. Duraia

Hydrogen peroxide (H₂O₂) is a ubiquitous molecule in biological systems, but at elevated concentrations, it exhibits cytotoxicity, necessitating precise monitoring for both biomedical and analytical applications.

Rapid, infection-free wound healing remains a critical challenge in regenerative medicine. This study presents the fabrication and evaluation of multifunctional electrospun polycaprolactone (PCL)-based scaffolds incorporating silver vanadate (AgVO ₃ ), hydroxyapatite (HAp), and graphene oxide (GO) for advanced wound care applications. AgVO ₃ offers potent antibacterial properties, HAp supports osteogenic and regenerative activities and GO enhances both mechanical performance and cellular interactions. The scaffolds exhibited a highly porous nanofibrous structure, mimicking the extracellular matrix (ECM) and promoting cell attachment, migration, and nutrient exchange. Comprehensive physicochemical characterization using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and field-emission scanning electron microscopy (FE-SEM) confirmed the successful integration of the composite. Mechanical testing revealed that GO-containing scaffolds significantly improved stiffness, with AgVO ₃ /GO@PCL and HAp/GO@PCL achieving Young’s moduli of 5.82 MPa and 4.36 MPa, respectively, which are substantially higher than that of neat PCL (1.39 MPa). In terms of flexibility, HAp/GO@PCL displayed the highest elongation at break (107.54%), indicating exceptional stretchability. The ultimate tensile strength was also enhanced in HAp@PCL (0.80 kJ/m ³ ) and AgVO ₃ /@PCL (0.88 kJ/m ³ ), highlighting their capacity to resist mechanical stress during application. Contact angle measurements showed that the AgVO ₃ -HAp/GO@PCL scaffold had the highest hydrophilicity (65.58° ± 5.97), compared to pure PCL (89.89° ± 3.70), indicating improved wettability, which is critical for fluid management and cell-material interactions at the wound interface. In vivo wound healing studies using a full-thickness rat model demonstrated that AgVO₃/GO@PCL scaffolds achieved 50% wound closure within 3 days, while AgVO₃-HAp/GO@PCL scaffolds facilitated complete re-epithelialization by day 14. Histological analysis confirmed enhanced collagen deposition and organized tissue architecture. The scaffolds also exhibited strong antibacterial activity, with large inhibition zones against S. aureus and E. coli . These findings position AgVO₃-HAp/GO@PCL scaffolds as promising candidates for next-generation wound dressings, offering a robust combination of mechanical resilience, bioactivity, antimicrobial efficacy, and moisture balance tailored for clinical wound-healing applications. Graphical Abstract

In the present work, we synthesized a novel ternary heterostructure nanocomposite comprising Silver Vanadate and Cerium Oxide Decorated Graphene Oxide (AgVO₃-CeO₂/GO) using a straightforward and cost-effective method. Six samples, including GO, CeO₂, CeO₂/GO, AgVO₃, AgVO₃/GO, and CeO₂-AgVO₃/GO, were prepared. The structural, morphological, electrochemical, and optoelectrical properties of these samples were thoroughly investigated. X-ray diffraction (XRD) demonstrated the presence of graphene oxide, cerium oxide, and silver vanadate phases, while transmission electron microscopy (TEM) showed the single crystalline nature of AgVO₃ and the dispersion of CeO₂ and AgVO₃ nanoparticles within the GO matrix. The heterojunctions between different components facilitated efficient charge transfer and enhanced optoelectronic performance. External quantum efficiency was measured using a 532 nm laser beam, and the electrical properties were evaluated under dark and illuminated conditions with a two-point probe setup. The inclusion of CeO₂ and AgVO₃ nanoparticles in the GO matrix improved charge transport and interfacial charge transfer processes. These findings highlight the potential of these materials for various optoelectronic applications, including photodetection, sensing, and energy harvesting, with further optimization potentially leading to high-performance devices with enhanced functionality and efficiency.

The present work reports the synthesis of multi-wall carbon nanotubes (MWCNTs) over graphite nanosheets by an easy and simple approach without using any external catalyst. Simply, yellow corn seeds were thermally annealed in a hydrogen atmosphere at 1050 °C for 3 h without any pretreatments. Notably, the growth of MWCNTs was observed to preferentially occur on the outer surface of the corn shell. This uncomplicated approach not only emphasizes the feasibility of synthesizing carbon nanomaterials using agricultural by-products but also underscores the potential applications of these synthesized materials in various fields. Samples were examined through a comprehensive analysis employing various techniques, including scanning electron microscopy (SEM), Raman spectroscopy, FTIR, X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The findings unveiled the formation of rolled graphene accompanied by the presence of vertical multi-wall carbon nanotubes (MWCNTs) positioned over stacked graphene sheets. This detailed characterization provides insights into the structural features and arrangement of the synthesized materials, paving the way for a deeper understanding of their potential applications. The pyrolysis temperature is a crucial factor in the morphological characteristics of the synthesized carbon nanostructures. While graphene cage-like structures were obtained at 800 °C, small carbon nanotubes were grafted to larger ones and formed three-dimensional hierarchical morphologies when the annealing temperature increased to 900 °C. The growth mechanism of the carbon nanotubes was explained based on the jet self-extrusion of the generated gases through the inherent pores of the corn seeds. The current technique employed in manufacturing MWCNTs shows significant promise as a green synthesis method for producing catalyst-free MWCNTs suitable for industrial applications including sensors and energy storage materials.

In this work, multi-walled carbon nanotubes (MWCNTs) were unzipped utilizing the modified Hummers technique as an effectual procedure to deliver highly unzipped graphene nanoribbons (GNRs) employed for the fabrication of a light sensor. The chemical unzipping was also attained by modifying the oxidation time to ensure a good unzipping efficiency and a higher rate of exfoliation of the MWCNTs. The influence of soaking time on the unzipping efficiency of the MWCNTs has been examined. Furthermore, SEM, TEM, FTIR, X-ray diffraction (XRD) and Raman examinations were utilized to monitor and characterize the process of unzipping of MWCNTs. Schottky diode based on the unzipping MWCNTs was fabricated. The optoelectrical properties of the chemically unzipped carbon nanotube (CNT) by the modified hummers method were studied. The high unzipping efficiency was a good technique used for the fabrication of a promising Schottky diode photosensor which was revealed by the I–V characteristics curves. A 532 nm laser was used to calculate the quantum efficiency. Based on the obtained results, the synthesized GNRs have very promising applications in many fields including micro and nano optoelectronics.

The light scribe (LS) technique has been applied to reduce graphene oxide (LSGO) over a flexible substrate to be used as a humidity sensor. Graphene oxide (GO) suspension was drop casted over Polyethylene terephthalate (PET) substrate and then reduced inside a conventional light scribe digital video disc (DVD). Interdigitated electrode was precisely fabricated with dimensions of the finger length of 450 μm and width of 20 μm. The prepared material was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Raman spectroscopy. The results confirm the reduction process of GO using the LS technique. Moreover, the humidity sensing properties of the LSGO was evaluated. Results showed that the present light-scribed humidity sensor has many advantages including rapid response, highly precise due to light scribe technique, and more importantly sensors can be fabricated directly on flexible substrates which are highly favorable for future wearable smart electronics.

In the present contribution, the 3D hollow structure of manganese cobalt oxide/carbon nanotubes (MnCo ₂ O ₄ /CNTs) nanocomposite was successfully synthesized through a co-precipitation procedure followed by post-heat treatment. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). Based on the obtained results, the surface of carbon nanotubes was coated uniformly in radial directions by manganese oxide (MnO ₂ ) nanosheets forming a flower-shaped structure. In the next step, cobalt oxide precursor was introduced to form MnCo ₂ O ₄ /CNTs nanocomposite. The XRD data confirms the formation of MnCo ₂ O ₄ /CNTs. The estimated values of the strain and the crystallite size based on the Williamson-Hall (W-H) method are calculated as 5.326 × 10 ⁻⁴ and 16 nm respectively. The fingerprint area of FTIR suggests the successful incorporation of MnO ₂ and cobalt oxide onto CNTs’ surfaces. The flower-shaped structure in the nanoscale is verified by the FESEM and TEM devices. Furthermore, the magnetic specifications revealed the paramagnetic with a small ferromagnetic component of the aforementioned MnCo ₂ O ₄ /CNTs nanocomposite.