Graphene Oxide Hybrid Research Articles

Preparation and Evaluation of pH-Sensitive Chitosan/Alginate Nanohybrid Mucoadhesive Hydrogel Beads: An Effective Approach to a Gastro-Retentive Drug Delivery System.

Despite extensive research over the decades, cancer therapy is still a great challenge because of the non-specific delivery of chemotherapeutic agents, which could be overcome by limiting the distribution of chemotherapeutic agents toward cancer cells. To reduce the cytolytic effects against cancer cells, graphene oxide (GO) nanoparticles (NPs) can load anticancer medicines and genetic tools. During the current study, folic-acid-conjugated graphene oxide (Fa-GO) hybrid mucoadhesive chitosan (CS)-based hydrogel beads were fabricated through an "ion-gelation process", which allows for regulated medication release at malignant pH. The fabricated chitosan-alginate (SA-CS) hydrogel beads were examined using surface morphology, optical microscopy, XRD, FTIR, and homogeneity analysis techniques. The size analysis indicated that the size of the Fa-GO was up to 554.2 ± 95.14 nm, whereas the beads were of a micrometer size. The folic acid conjugation was confirmed by NMR. The results showed that the craggy edges of the graphene oxide were successfully encapsulated in a polymeric matrix. The mucoadhesive properties were enhanced with the increase in the CS concentration. The nanohybrid SA-CS beads exhibited good swelling properties, and the drug release was 68.29% at pH 5.6 during a 24 h investigation. The accelerated stability study, according to ICH guidelines, indicated that the hydrogel beads have a shelf-life of more than two years. Based on the achieved results, it can be concluded that this novel gastro-retentive delivery system may be a viable and different way to improve the stomach retention of anticancer agents and enhance their therapeutic effectiveness.

Study of the effect of N, N-diethyl hydroxyl amine/multi-layered graphene oxide hybrid on reducing cathodic delamination and increasing corrosion resistance of epoxy coating on steel substrate

In this study, a hybrid of multi-layered graphene oxide (MLGO) and oxygen absorbent corrosion inhibitor N, N-diethyl hydroxylamine (DEHA) was investigated. The nano hybrid was prepared in order to reduce the amount of cathodic delamination and increase the corrosion resistance of the epoxy coating. Epoxy coatings were prepared using the optimal percentage of 0.75 wt. % of the nano hybrid with different ratios between MLGO and DEHA like (1:2), (1:1) and (2:1). Mapping energy-dispersive X-ray spectroscopy, thermo gravimetry analysis and Fourier transform infrared (FT-IR) analysis indicated the uniform distribution of the inhibitor throughout the MLGO structure and the hydrogen bond interactions between them. The results of FT-IR spectroscopy: attenuated total reflectance test after six months confirmed the presence and stability of the inhibitor in the coating. Also, the results of 800 h of salt spray test and the long-term electrochemical impedance test after 7 months showed that the epoxy coating, containing MLGO-DEHA (1:2) had the highest corrosion resistance (2.54 × 107 Ω cm2) and the lowest cathodic delamination (15.9%). The results were also confirmed by cathodic delamination and pull-off adhesion tests.

Numerical study of magneto convective ag (silver) graphene oxide (GO) hybrid nanofluid in a square enclosure with hot and cold slits and internal heat generation/absorption

Energy transmission is widely used in various engineering industries. In recent times, the utilization of hybrid nanofluids has become one of the most popular choices in various industrial fields to increase thermal performance and enhance power generation, entropy reduction, solar collectors, and solar systems. Motivated by this wide range of applications, the present article explores the mixed convection flow and heat transfer of magnetohydrodynamic \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:Ag$$\\end{document} (Silver) and \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:GO$$\\end{document} (Graphene) nanofluids hybrid nanofluids in a square enclosure with heat generation/absorption by using the MAC method. The vertical walls of the enclosure are assumed to be adiabatic. The horizontal walls are also assumed adiabatic except for the center portion of the top and bottom walls of the cavity. The center portion of the horizontal upper wall is maintained as a cold is \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{(T}_{c})$$\\end{document}and the lower wall is maintained as hot \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\left({T}_{h}\\right)$$\\end{document}. The dimension equations are transformed into dimensionless form and then discretized and solved with the finite difference Marker and cell (MAC) method. Numerical modelling is implemented, by changing Richardson number \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\left(Ri\\right)$$\\end{document}, The results are located graphically using MATLAB software. The Nusselt number graph was displayed for the Reynolds number (Re), Richardson number\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\:\\left(Ri\\right)$$\\end{document}, and Hartmann number \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\left(Ha\\right)$$\\end{document}. The findings show that enhancing the values of the Richardson number and Reynolds number enhances the Nusselt number values except for the Hartmann number. The findings indicate that the combination of the new model is very good at predicting thermal conductivity and correlates experimental results well. The augmenting strength of magnetic force diminishes fluid flow. Developing the coefficients for the heat source and sink improves energy transmission and heat transfer enhancement. Hybrid nanofluids like \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:Ag-GO$$\\end{document} enhance heat transfer and efficiency. They improve cooling in heat exchangers, radiators, and electronics, boost solar energy systems, aid in cancer treatment and drug delivery, enhance geothermal and wind turbine efficiency, and improve manufacturing processes. Overall, they optimize thermal management in various applications.

Enhanced Thermal Conductivity and Stability of Hydrated Salt Phase Change Microcapsules With GO/SiO2 Hybrid Shell for Battery Thermal Management

AbstractHerein, the synthesis of a novel microencapsulated phase change material via a sol–gel method is presented, featuring disodium hydrogen phosphate dodecahydrate as the core and a SiO2/graphene oxide composite as the shell. The morphology and core–shell microstructure of the synthesized microcapsules are characterized using scanning electron microscopy. The phase change performance and thermal stability are evaluated by differential scanning calorimetry and a high/low temperature test chamber, respectively. Energy dispersive X‐ray spectroscopy and Fourier transform infrared spectroscopy are employed to determine the chemical composition of the microcapsules. The findings reveal that the MEPCM exhibited a high melting enthalpy of 174.3 J g−1. The degree of supercooling is reduced by 2.1 °C, and after 600 thermal cycles, the phase change enthalpy of the microcapsules showed a minor decrease of ≈6.0%. Notably, the thermal conductivity of the microcapsules is significantly enhanced, increasing by up to 51.8%. When integrated into the thermal management systems of lithium‐ion batteries, the MEPCM effectively maintained the battery temperature below 46 °C under a 3 C charging rate. In summary, these results suggest that the hydrated salt microcapsule with its hybrid silica and graphene oxide shell is a promising material for the thermal management of lithium‐ion batteries.

The Construction of Face-to-Face Combination between NiFe-layered Double Hydroxide Nanosheets and Monolayer rGO for Efficient Water Splitting and Oxygen Reduction.

Developing cost-effective and efficient electrocatalysts is essential for advancing a green energy future. Herein, a NiFe-layered double hydroxide loaded on reduced graphene oxide (NiFe-LDHs@rGO) hybrid was synthesized using a straightforward three-step process involving exfoliation tearing, electrostatic self-assembly, and chemical reduction. The face-to-face packing and ultrathin exfoliation enable strong heterogeneous interactions, fully harnessing the potential of these complementary two-dimensional counterparts. Consequently, the resultant catalyst displays outstanding oxygen evolution reaction (OER) catalytic activity and stability, whose overpotential is as low as 241 mV at 30 mA cm-2 and 255 mV at 50 mA cm-2 with a low Tafel slope of 62.1 mV dec-1. Both the experimental results and density functional theory (DFT) calculations reveal that the face-to-face assembly strengthens the electronic interactions between NiFe-LDHs and rGO, which effectively modulates the d-band center of Ni and Fesites and improves the reaction kinetics for OER. Moreover, the resultant NiFe-LDHs@rGO hybrids exhibit excellent multifunctional catalytic performance. Its hydrogen evolution reaction (HER) activity is endowed by Fe-site of NiFe-LDHs and defect states rGO and achieves a low voltage of 1.68 V to drive a current density of 10 mA cm-2 for overall water splitting. The face-to-face heteroassembly also imparts NiFe-LDHs@rGO with superior oxygen reduction reaction (ORR) activity, with a half-wave potential of 0.70 V and a limiting current density of 4.2 mA cm-2. Its ORR primarily follows a four-electron transfer pathway with a minor contribution from a two-electron process. This study establishes the groundwork for optimizing two-dimensional heterogeneous interfaces in LDH@carbon-based materials for advanced energy conversion.

Explore the effect of magnesium oxide nanoparticles decorated graphene oxide hybrid nanofillers reinforced polyaniline ternary nanocomposites on optical, thermal, and dielectric properties

The Neem (Azadirachta indica) leaves utilized for the synthesis of magnesium oxide nanoparticles (MgONPs) are readily available and pose little risk of harm. The MgONPs@GO hybrid nanofillers are synthesized through in situ method and is reinforced with polyaniline (PANI) to enhance its electrical characteristics and thermal stability. The UV-visible spectroscopy demonstrates the formation of a charge transfer complex in the PANI/MgONPs@GO ternary nanocomposites. The presence of functional groups in the PANI/MgONPs@GO ternary nanocomposites was detected using Fourier transform infrared (FTIR) spectroscopy. The crystalline phases of the PANI/MgONPs@GO ternary nanocomposites were validated using x-ray diffraction (XRD) investigation. The scanning electron microscopy (SEM) technique was used to investigate the nanostructured morphology of the PANI/MgONPs@GO ternary nanocomposites. The thermogravimetric analysis (TGA) revealed that the PANI/MgONPs@GO ternary nanocomposites exhibited greater thermal stability compared to the pure PANI. The AC conductivity (σ ac), dielectric permittivity (ε′), and dielectric loss (tanδ) of PANI/MgONPs@GO ternary nanocomposites exhibit a substantial increase compared to pure PANI.

Efficient transformation of CO2 into α-alkylidene cyclic carbonates over Cu0/Cu+ derived from CuAl layered double hydroxide/reduced graphene oxide hybrid

A simple liquid-phase co-precipitation method was used to achieve a good dispersion of CuAl layered double hydroxide (CuAl-LDH) on the surface of graphene oxide (GO), and Cu2+ in the lattice of CuAl-LDH was in-situ reduced to Cu0 and Cu+ species, resulting in the preparation of R-CuAl-LDH/rGO catalyst. It could effectively catalyze the cyclization of CO2 and propargylic alcohols under mild conditions (50 °C and 1 bar), and the yield exceeded 99 % within only 40 min. Systematic characterization revealed that two-dimensional LDH nanosheets were grown on the rGO surface in an irregular orientation, leading to a higher specific surface area and more abundant surface active sites. Meanwhile, the synergistic catalysis of Cu0 and Cu+ dual-active sites greatly enhanced the catalytic efficiency. In addition, the catalyst had excellent recycling properties with no significant loss of activity after 5 cycles of continuous operation.

Facile interface engineering of highly stable covalently functionalized graphene oxide-nickel based metal organic framework heterostructures for supercapacitor applications

This study presents the synthesis, characterization and electrochemical studies of the covalently connected 2D/2D heterostructures of nickel-based metal-organic framework (Ni-MOF)/graphene oxide (GO) hybrids. The covalent linkage in GO plays a vital role in the growth of Ni-MOF onto the functionalized GO and these hybrids (NG) show fascinating structural properties. An appreciable reduction of GO is observed in NG hybrids with an increase in Ni-MOF concentration. The NG hybrids display exceptional structural stability with a maximum of 96 % capacitance retention even after 10,000 cycles and augmented electrochemical performance (151.8 F g-1 at a current density of 0.5 A g-1).

Synergetic benefits of zinc antimony oxide/reduced graphene oxide hybrid anode for enhanced sodium-ion storage

Organic-inorganic hybrid nanocomposites are rapidly evolving as a new generation of materials with attractive properties for electrochemical energy storage. Unfortunately, their practical applications in sodium-ion batteries (SIBs) still require further research due to the unsatisfactory cycling stability and rate performance. This work explores using zinc antimony oxide/reduced graphene oxide (ZSO/rGO) hybrid nanocomposite as an anode material in SIBs. After 150 cycles at 0.05 A g−1, the ZSO/rGO electrode delivers a specific capacity of 357.21 mAh g−1 with a coulombic efficiency of 99.3 %, which is almost 2.5-fold higher than the specific capacity of the pristine ZSO electrode. An in-situ Raman spectroscopy study demonstrates that the sodiation/desodiation mechanism in the ZSO/rGO electrode involves the conversion and alloying reactions in the ZSO nanoparticles. Further electrochemistry analysis reveals that the nanocomposite anode shows synergistic effects by coupling diffusion and surface contribution, in which the latter plays an important role.

Enhancing mechanical and corrosion properties of GO and Al2O3 reinforced Cu composite coatings

Despite their significant functions and properties, the performance characteristics of Al2O3 ceramic particles and graphene oxide (GO) within hybrid copper composite coatings have been seldom investigated. This study successfully fabricated a Cu-GO- Al2O3 composite coating featuring fine particulate spherical network-like structures on St37 low carbon steel using an ultrasonic-electroless coating method. The effects of Al2O3-decorated graphene oxide hybrid reinforcement on the texture and nanomechanical properties of the copper matrix were examined. The tribological performance of the Cu-GO- Al2O3 composite coating under dry sliding conditions was evaluated, and the wear mechanism was investigated in detail. Results demonstrate that the Cu-GO- Al2O3 composite coating effectively reduces the wear rate and friction of the GO/ Al2O3 hybrid reinforced composite coating. Potentiodynamic polarization tests indicated that the Cu-GO- Al2O3 composite coating exhibits higher corrosion resistance compared to the copper matrix. The enhanced mechanical, tribological, and corrosion properties of the Cu-GO- Al2O3 composite coating are primarily attributed to: (i) the fine particulate spherical network-like structure; (ii) the synergistic effect of the GO and ceramic particle hybrid with a decorated structure; (iii) the formation of graphene oxide/ Al2O3 nanorolls in tribofilms and the excellent self-lubrication properties of graphene oxide. The Cu-GO- Al2O3 composite coating significantly improves the frictional and electrochemical properties of the copper matrix, offering new perspectives for next-generation electrical contacts and nanoelectromechanical systems.

Strategically engineered multifunctional graphene oxide hybrid nanomaterials for efficient catalytic degradation and emerging contaminants treatment

The use of functional textiles is growing in all fields of science and technology. Surface functionalization is mainly used to impart conventional textiles with new functionalities and improved performances. In the present study, a cobalt ferrite nanoparticle/graphene oxide (CoFe2O4/GO) coated polyethylene terephthalate (PET) fabric with excellent catalytic and antibacterial properties, has been successfully developed. The PET-coated CoFe2O4/GO samples, ranging from 1 % to 5 % wt. were obtained using a simple dip-coating method in CoFeO/GO solution (1 mg/mL), and were investigated through several physiochemical characterization techniques. CoFe2O4/GO and PET fabric have been shown to establish an interfacial connection by Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) results showed that CoFe2O4/GO coating did not affect the PET crystallinity and that CoFe2O4/GO hybrid was incorporated in the PET samples, which was proved as well by the morphological study through Scanning electron microscopy (SEM). Furthermore, thermogravimetric characterisation (TGA) verified that the coating does not change or impair the quality of the fibre and that the PET@CoFe2O4/GO as made is thermally stable. Tensile strength tests demonstrated that coated fabrics exhibited outstanding mechanical properties in comparison with pristine PET. Moreover, the coated PET@CoFe2O4/GO fabric was used as a model catalytic system for peroxymonosulfate (PMS) activation in the rhodamine B (RhB) degradation reaction. Total Organic Carbon (TOC) measurements showed that TOC removal reached 89.82 % in only 12 min reaction. The results confirmed that the coated fabrics exhibited high catalytic performances, good stability and reusability in consecutive degradation experiments with a degradation rate over 60 % even after 7 degradation cycles; Moreover, it is easily and simply separated from the mixture, by removing the textile sample from the aqueous solution. It is worth mentioning that the PET@CoFe2O4/GO fabrics showed outstanding antibacterial activity against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria with an inhibition diameter zone of up to 13 mm for PET@CoFe2O4/GO (5 %). Overall, these findings are of great importance as they permit the development of a novel multifunctional textile fabric, combining anti-bacterial activity, catalytic performance and mechanical properties. The study provides a textile-based catalyst with improved catalytic performance, re-usability in consecutive degradation reactions and easy catalyst separation compared to traditional supports. Thus, a huge potential application in several fields such as medicine, heterogeneous catalysis, and wastewater treatment.

A robust amphiphilic ionic covalent organic framework intercalated into functionalized graphene oxide hybrid membranes for ultrafast extraction uranium from wastewater

The efficient capture of uranium from wastewater is crucial for environmental remediation and the sustainable development of nuclear energy, yet it poses considerable challenges. In this study, amphiphilic ionic covalent organic framework intercalated into graphene oxide (GO) nanosheets functionalized with polyethyleneimine (PEI) were used to construct hybrid membranes with ultrafast uranium adsorption. These hybrid membranes achieved equilibrium in just 10 min and the adsorption capacity was as high as 358.8 mg g−1 at pH = 6. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses revealed that the strong interaction between sulfonic acid groups and uranyl ions was the primary reason for the high adsorption capacity and selectivity. The extended transition state and natural orbitals for chemical valence (ETS–NOCV) analysis revealed that the interaction between the 7 s and 5f orbitals of uranyl and the 2p orbitals of S and O in the sulfonate was the primary reason for the strong interaction between the sulfonate and the uranyl ion. This research presents an effective method for the rapid extraction of uranium from wastewater.

Preparation and application of graphene oxide hybrid polyaniline based flexible electrode materials

Flexible electrode materials refer to materials used as electrodes in electronic devices, which have characteristics such as softness, flexibility, and stretchability, and are suitable for the preparation of various flexible electronic devices. In this study, in order to optimize the problems of poor specific capacity, low conductivity, and instability of conventional flexible electrode materials, the performance and reliability of the flexible electrode materials were improved by hybridizing graphene oxide (GO) and polyaniline (PANI). In this paper, graphene oxide – polyaniline (GO-PANI) flexible electrode materials were prepared and tested for their performance using graphene and polyaniline. In the experiments, a current density of 1 A/g was selected for the constant current charge/discharge test of GO-PANI electrode materials with different graphene contents to evaluate the performance of GO-PANI electrode materials in energy storage. After the experiments, it was proved that the charge/discharge times of GO-PANI electrode materials were 1430s, 1625s, and 1495s when the graphene content was 1%, 3% and 5%, respectively, and the GO-PANI (3%) electrode material had the longest charge/discharge time. Accordingly, it can be concluded that GO-PANI (3%) electrode material had the best energy storage performance, which could realize a stable and efficient charging and discharging process, and could be used as an ideal electrode material in flexible electronic devices. The research in this paper could provide new ideas and solutions for the development of flexible electrode materials and promote the further development and application of flexible electronics technology.

Facile preparation of graphene–graphene oxide liquid cells and their application in liquid-phase STEM imaging of Pt atoms

Graphene–graphene oxide (GO) hybrid liquid cells (LCs) for liquid-phase scanning transmission electron microscopy (STEM) were fabricated using a facile method with commercial graphene on a polymethyl methacrylate sheet and GO on a TEM grid. LCs containing Pt nanoparticles (NPs) and pure water were efficiently produced and observed via STEM. Their composition and thickness were characterized by STEM-electron energy-loss spectroscopy. High-resolution (HR) STEM revealed slow-moving Pt NPs’ atomic structures and fast-moving single Pt atoms at the LC’s thin edges. Minimal damage during HR STEM indicated stable LCs because of their excellent electrical and thermal conductivities and radiolysis species scavenging ability.

GREEN SYNTHESIS OF MAGNETIC REDUCED GRAPHENE OXIDE HYBRID NANOCOMPOSITE USING NOVEL CLERODENDRUM PANICULATUM FOR THE REMOVAL OF MB DYE AND Cd (II) FROM AQUEOUS SOLUTION VIA MAGNETIC SEPARATION

The utmost dangerous and significant source of environmental contamination is constituted by ionic dyes and heavy metals. Graphene oxide (GO) can eradicate heavy metal ions and dyes from effluent, but the major difficulty associated with GO is the inconvenience during separation. In this study, magnetic reduced GO (rGO-Fe3O[Formula: see text] hybrid nanocomposite is synthesized by using the novel green reducing agent and is used as an adsorbent for the removal of methylene blue (MB) dye and Cd (II) ions. The prepared samples are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and FTIR spectroscopy. adsorption study of rGO-Fe3O4 is carried out using UV visible spectrophotometry and it is obtained that the maximum adsorption capacity in the mono component system using double distilled water for MB dye and Cd (II) ions is 64.52 and 93.49[Formula: see text]mg/g, respectively. Moreover, the effect of different parameters such as temperature, adsorbent dosage, contact time, pH and initial adsorbate concentration on the adsorption of heavy metal and dye is investigated.

Mechanical and Microstructural Analysis of High-Performance Concrete Incorporated with Hybrid Fibres and Graphene Oxide

Mechanical and Microstructural Analysis of High-Performance Concrete Incorporated with Hybrid Fibres and Graphene Oxide

Thermal characteristics of nanofluid ice slurry flowing through a spiral tube: A computational study

Nanofluid ice slurry (NICS) has recently attracted significant attention in the field of thermal engineering as an alternative refrigerant, offering a cost-effective, stable, and environmentally friendly cold storage solution. To maximize its potential, a thorough understanding of its heat transfer characteristics is crucial. Unfortunately, this information is not available for spiral tubes which are commonly used in thermal systems due to their superior heat transfer performance. This may hinder further development and implementation of this technology. Hence, the present investigation aims to analyze the flow characteristics and heat transfer mechanisms of a graphene oxide hybrid NICS within a spiral tube employing a computational fluid dynamics (CFD) methodology. More specifically, an interphase heat and mass transfer model, derived from the Euler–Euler model, is formulated to accurately represent the phase transition phenomena occurring within the nanofluid. The results indicate that the spiral tube structure enhances ice crystal accumulation inside the tube, leading to lower outlet temperatures and improved heat transfer without causing ice blockage. The NICS shows a 3% higher pressure drop compared to pure water ice slurry. Increased nanoparticle concentrations enhance thermal conductivity, benefiting heat transfer, but also raise viscosity, resulting in greater internal friction. A Nusselt correlation based on Prandtl and Dean numbers is formulated to aid future studies and the design of NICS systems. When the Reynolds number increases from 3600 to 6600, the Nusselt number rises by approximately 21% for pure water ice slurry and 22% for nanofluid ice slurry.

Photothermal responsive porous hollow microneedles as Chinese medicine versatile delivery system for wound healing.

Chinese medicine is identified as a candidate for wound healing. Attempts in this field tend to develop efficient dosage forms for delivering Chinese medicine with low side effects. In this paper, we proposed novel photothermal responsive porous hollow microneedles (PRPH-MNs) as a versatile Chinese medicine delivery system for efficient antibacterial wound treatment. The PRPH-MNs are composed of porous resin shells with good mechanical property, hydrogel cores, and a photothermal graphene oxide hybrid substrate. The hollow structure provides sufficient space for loading the drug dispersed hydrogel, while the porous resin shells could not only block the direct contact between drugs and wound sites but also provide channels for facilitating the drug release from the core. In addition, benefiting from the photothermal effect of their substrate, the PRPH-MNs could be heated under near-infrared (NIR) irradiation for controllable promotion of drug release. Based on these features, we have proved that the antibacterial Chinese medicine Rhein loaded PRPH-MNs were effective in promoting wound healing due to their good antibacterial property and on-demand drug release. Thus, we believe that the proposed PRPH-MNs are valuable for delivery of different drugs for clinical applications.

Synergistic nanomaterial system for luminescence sensing of MnO4- anion and enhanced photocatalytic removal of antibiotic chloramphenicol (CAP) in aqueous environments using Dy3+/Tb3+ co-doped NaYF4 and graphene oxide hybrid

The presence of industrial pollutants in water bodies, particularly metal anions and organic pollutants, has put human health and the environment at risk worldwide, triggering the research and development of multifunctional nanoparticles that not only have excellent luminescence detection ability but also possess simultaneous photo-degradation activity against harmful pollutants. Herein, we have synthesized Dy3+/Tb3+ co-doped NaYF4 (Tb-NP) and (Tb-GO) NaYF4:Dy3+/Tb3+@GO(GO=Graphene oxide) nano hybrids via hydrothermal approach and tested their functional activity for the fluorescence selective detection of MnO4- anions and photocatalytic degradation of drug Chloramphenicol (CAP) in aqueous medium. The physicochemical characterization of prepared nanosamples was examined utilizing variety of analytical methods. The luminescent property of NaYF4:Dy3+/Tb3+(7 %) revealed that it is exceptionally sensitive and selective towards the detection ofMnO4- anion in aqueous medium. It was observed that, when varied amount of MnO4- anion was added to a suspension solution containing the synthesized NaYF4:Dy3+/Tb3+(7 %) chemosensor, the photoluminescence emission band at 545 nm was significantly quenched. Moreover, NaYF4:Dy3+/Tb3+(Tb-NP) exhibited the limit of detection (LOD)value of 0.65 ppm along with high Stern-Volmer (Ksv) quenching constant value of 4.75 ×105 M−1 for MnO4- anion, indicating great selectivity and sensitivity of the designed nanosensors towards MnO4- anion. Further, the Graphene oxide (GO) conjoined NaYF4:Dy3+/Tb3+(7 %) nanohybrid showed accelerating photocatalytic activity toward the degradation of CAP in aqueous medium under UV-irradiation. The obtained results of UV-Vis spectroscopy clearly indicate that NaYF4:Dy3+/Tb3+@GO (Tb/GO) nanohybrid can act as a superior nanocatalyst than that of NaYF4:Dy3+/Tb3+(Tb-NP) nanophosphors. The photocatalytic efficiency of NaYF4:Dy3+/Tb3+@GO (Tb/GO) nanohybrid toward degradation of CAP is around 95.6 % within 50 minutes under UV light and it maintains remarkable stability even after five repeated catalytic cycles. In conclusion, this study presents a feasible method for immediate detection of MnO4- anion and improved photo-catalytic degradation of CAP in an aqueous medium employing NaYF4:Dy3+/Tb3+(Tb-NP) and NaYF4:Dy3+/Tb3+@GO (Tb/GO) as dual functional nanomaterials.

Multi-compartmentalized electrochemical sensing platforms for monitoring cascade enzymatic reactions

Designing an electrochemical biosensor with the required features is a complex process involving multiple factors. For instance, nanocomposite materials used ensure the adaptation of the sensor to specific parameters on demand. But beyond making more versatile sensors, these materials likely offer excellent sensing platforms to mimic biological processes (e.g. cell communication) on the electrode surface. For this, developed methods are needed to integrate non-conductive nanoreactors for molecular communication into a biocompatible matrix on electrode surfaces with the request of spatially separated and controlled enzyme localization. Here, we present a novel reduced graphene oxide hybrid material to immobilize polymeric nanoreactors supported by an alginate network as a matrix on the electrode surface. The possibility of introducing cascade reactions in an electrochemical biosensor has the advantage of broadening the target substrates as well as their selectivity using enzymes in different nanocompartments (=compartmentalization). The polymeric vesicles allow the loading of enzymes or artificial enzymes, offering active center retention and long-term enzyme stability. Firstly, the inclusion of spatially separated polymeric active nanocompartments into the matrix on the electrode surface is used to monitor a simple enzyme reaction. However, the study’s accomplishment lies in its successful ability to monitor an enzyme cascade reaction, one producing and the other consuming hydrogen peroxide, hosting natural and artificial enzymes. This proof-of-concept generates an important contribution to the design of analytical platforms capable of detecting complex environments or even monitoring communication between cell-like structures, extremely useful for fields such as synthetic biology, biomimetics and advanced biosensors.