A novel highly efficient and ultrasensitive electrochemical detection of toxic mercury (II) ions in canned tuna fish and tap water based on a copper metal-organic framework.

Invisible mercury ion is an incredibly toxic pollutant to the atmosphere. Thus a quick and sensitive detection method is of considerable importance for toxicological assessment, environmental protection and human health. A novel electrochemical sensing system has been developed for the detection of mercury (Hg2+) ions in canned tuna fish and tap water. The sensing platform was developed on the cubic copper-metal-organic framework (Cu-MOF) based nanoparticles. Cu-MOF has a porous architecture with a large, unique surface area that is favorable for mercury ions adsorption and preconcentration. The electrochemical properties of Cu-MOF nanoparticles modified electrode were investigated. Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were applied for the detection of mercury in 0.1 M phosphate buffer (PB) at pH 9 under ambient conditions. Under optimized conditions, the limit of detection (LOD) for Hg2+ is around 0.0633 nM with a linear range of 0.1-50 nM. Cu-MOF nanoparticles were successfully applied to the analysis of mercury ions in canned tuna fish and tap water. The developed sensor demonstrated satisfactory anti-interference, reproducibility, reliability, repeatability and applicability for the detection of mercury ions. This proof of principle serves as a steppingstone towards promoting ultrasensitive and precise assay for the detection of mercury.

In Situ Charge Transfer at the Ag@ZnO Photoelectrochemical Interface toward the High Photocatalytic Performance of H2 Evolution and RhB Degradation.

Designing an efficient hybrid structure photocatalyst for photocatalytic decomposition and hydrogen (H2) evolution has been considered a great choice to develop renewable technologies for clean energy production and environmental remediation. Enhanced charge transfer (CT) based on the interaction between a noble metal and a semiconductor is a crucial factor influencing the movement of photogenerated electron-hole pairs. Herein, we focus on the recent advances related to plasmon-enhanced noble metals and the semiconductor nature to drive the photocatalytic H2 production and photodegradation of the organic dye rhodamine B (RhB) under UV and visible light irradiation. Specifically, the combination of concerted catalysis and green nanoengineering strategies to design ZnO-based composite photocatalysts and their decoration with metallic Ag have been realized by the radio frequency (RF) sputtering technique at room temperature. This simultaneity enhances the interface coupling between Ag and ZnO and reduces the energy threshold. The creation of charge transfer in the heterojunction and Schottky barrier changes the photoelectronic properties of the as-synthesized Al-doped ZnO (AZO); afterward, these effects promote the migration, transportation, and separation of photoinduced charge carriers and enhance the light-harvesting efficiency. As a result, the as-synthesized AZO-20 hybrid nanostructure exhibits a photocurrent density of 2.5 mA/cm2 vs Ag/AgCl, which is improved by almost 12 times compared with that of bare ZnO (0.2 mA/cm2). The hydrogen evolution rates of AZO-20 were ∼38 and ∼24 µmol/h under UV and visible light exposure, which are almost five- and tenfold higher than those of pristine ZnO, respectively. Additionally, the RhB degradation efficacies of the obtained AZO-20 were greater than almost 97 and 82% under UV and visible light illumination, respectively. The achieved apparent rate constant for the photocatalytic RhB decomposition was 0.014 min-1, indicating that it is 14-fold than that in pristine ZnO (0.001 min-1). Heterostructure AZO photocatalysts possess excellent practical stability in the water-splitting reaction and photocatalytic RhB decomposition, posing as promising candidates in practical works for pollution and energy challenges.

The role of alloyed strontium in the microstructures and alkaline electrochemistry of Mg-5Al-4Sn alloys.

In this study, strontium is used as an alloying element for improving the pitting resistance of Mg-5Al-4Sn based alloys in an alkaline solution. Potentiodynamic polarization measurements suggest that the addition of strontium increases the robustness of the pitting resistance as a result of the higher pitting potential and wider range of passive potential. Electrochemical impedance spectroscopy (EIS) confirms the formation of a solid passive film on the alloy surface due to a significant increase in the passive film and the charge transfer resistance, as well as lower film and double layer constant phase element magnitude values. Additionally, the potentiostatic polarisation results also show a lower passive current density and passive film stability, resulting in an increase in the breakdown time when the amount of strontium added to the alloy increases from 0.0 to 1.0 wt%. Furthermore, the scanning electron microscopy results indicate that insignificant corrosion is observed on alloy specimens containing strontium, whereas there is fierce corrosion on alloy based surfaces. This robust corrosion resistance could be attributed to the α-grain reduction and refined precipitates at the alloy grain boundaries, resulting in promoted formation of the passive film which is formed from a mixture of magnesium, aluminum and tin oxides/hydroxides, as confirmed by the X-ray photoelectron spectroscopy results.

Low-potential immunosensor-based detection of the vascular growth factor 165 (VEGF165) using the nanocomposite platform of cobalt metal-organic framework.

The vascular endothelial growth factor 165 (VEGF165) is a quintessential biomarker in cancers. An easy and precise tool for the early detection of malignancies is required for rapid care and metastasis prevention. Cobalt-based metal-organic framework (Co-BTC-GO-MOF) nanoparticles have been used as a signal carrier for the anti-VEGF165 signaling antibody. Cobalt-based MOF was synthesized using cobalt (Co), benzene-1,3,5-tricarboxylate (BTC), and graphene oxide (GO) applying a hydrothermal method. Structure, compositions, size and morphology of the qualified sensor are determined by using distinctive analytical techniques. The Co-MOF nanoparticles are found to be thermostable, as revealed by thermal stability assay. The strategy utilises an impedimetric and differential pulse voltammetry (DPV) techniques in the presence of the [Fe(CN)6]3-/4- redox system. Compared to earlier results, this assay resulted in higher sensitivity with the limit of detection (LOD) found to be 5.23 pM in a 0.01 M buffer solution of pH 7.4 using linear scale voltammetry at room temperature. The resulting Co-BTC-GO-MOF immunosensor shows high responsiveness and selectivity in detecting VEGF165 in real-time serum samples of cancer patients. The electrochemical performance studies confirm that the intended proposed immunosensor could pave the way for the future advancement of high-performance, sensitive, reproducible and robust immunosensors for the cost-effective and initial phase detection of cancer in the future.

Improved Corrosion Resistance of Steel in Ethanol Fuel Blend by Titania Nanoparticles and Aganonerion polymorphum Leaf Extract.

A porous and low-density protective film on a steel surface in the corrosive environment can undergo deterioration even in the presence of organic inhibitors due to infiltration of aggressive ions into the pinholes and/or pores. This phenomenon is related to the localized corrosion that takes place even in the presence of an optimal concentration of organic corrosion inhibitors in the given medium. To overcome this issue, we have designed an organic protective film on a steel surface with the help of titania nanoparticles (TNPs) combined with an organic corrosion inhibitor derived from Aganonerion polymorphum leaf extract (APLE), all to be studied in a simulated ethanol fuel blend (SEFB). The TNPs with varied diameters and concentrations have been studied for examining their effect on the inhibition capacity of 1000 ppm APLE on the steel surface in SEFB medium using electrochemical and surface analysis techniques. Enhanced corrosion inhibition of the surficial film was observed in the presence of both the APLE inhibitor and small amounts of TNPs. A direct agreement was observed between the experimental and molecular dynamics theoretical investigations showcasing high binding energy between inhibitor molecules and steel substrates, resulting in a much higher adhesion of the protective film, good thermal stability of the adsorbent film, and electron abundance for the supply of steel substrate of inhibitor species.

A dual synergistic of curcumin and gelatin on thermal-responsive hydrogel based on Chitosan-P123 in wound healing application.

This study aimed to fabricate the potential therapeutic scaffold to efficiently and safely fastening skin wound healing. A biocompatible grafting polymer-based thermal sensitive hybrid hydrogel (Chitosan-P123, CP) containing gelatin and curcumin was designed to be suitable stiffness for tissue regeneration. A detailed in the rheological study found that the encapsulated agents induced the change in the stiffness of the hydrogel from the hard to the soft. Especial, the thermally induced phase transition of CP hydrogel was governed by the participant of gelatin rather than curcumin. For example, at 25 wt% gelatin, CP hydrogel exhibited a unique gel-sol-gel transition following the function of temperature. Moreover, in vitro investigation revealed that the hybrid hydrogel provides the capacity of especially induced curcumin release with a sustainable rate as well as the excellent biocompatibility scaffold. Altogether with in vivo study, the hybrid hydrogel highlighted the advance of the dual synergistic of curcumin and gelatin in development of smart scaffold system, which promoted the efficacy in the regeneration of the structure and the barrier's function of damaged skin such as wound or skin cancer.

A Study on Corrosion Inhibitor for Mild Steel in Ethanol Fuel Blend.

The main aim of this study is to investigate Aganonerion polymorphum leaf-ethyl acetate extract (APL-EAE) and its inhibiting effect for steel in ethanol fuel blend. The immersion test, electrochemical and surface analysis techniques were successfully carried out in this research. Scanning electron microscope images indicated that the ethanol fuel blend induced pitting corrosion of steel. Remarkably, the surface of the sample containing 1000 ppm APL-EAE is smoother than the others submerged in different conditions. The electrochemical impedance spectroscopy result shows that APL-EAE has formed a good protective layer, preventing corrosive factors from hitting the steel surface. The potentiodynamic polarization data argue that the corrosion inhibition efficiency was strengthened with the increase of APL-EAE concentration. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated less intensity of Fe peaks, higher intensity of C1s peak and the appearance of organic peaks (N1s, P2p, O1s) from specimens with and without APL-EAE addition. Therefore, the results suggest the formation of the protective film on steel surface and affirm that APL-EAE has served as an effective corrosion inhibitor for steel in ethanol fuel blend.