Pyrene Derivative Incorporated Ni MOF as an Enzyme Mimic for Noninvasive Salivary Glucose Detection Toward Diagnosis of Diabetes Mellitus.

Herein, we demonstrate the detection of glucose in a noninvasive and nonenzymatic manner by utilizing an extended gate field-effect transistor (EGFET) based on the organic molecule pyrene phosphonic acid (PyP4OH8) incorporated nickel metal-organic framework (NiOM-MOF). The prepared electrode responds selectively to glucose instead of sucrose, fructose, maltose, ascorbic acid, and uric acid in a 1× phosphate buffer saline solution. Also, utilizing the scanning Kelvin probe system, the sensing electrode's work function (Φ) is measured to validate the glucose-sensing mechanism. The sensitivity, detection range, response time, limit of detection, and limit of quantification of the electrode are determined to be 24.5 µA mM-1 cm-2, 20 µM to 10 mM, less than 5 s, 2.73 µM, and 8.27 µM, respectively. Most interestingly, the developed electrode follows the Michaelis-Menten kinetics, and the calculated rate constant (km) 0.07 mM indicates a higher affinity of NiOM-MOF toward glucose. The real-time analysis has revealed that the prepared electrode is sensitive to detect glucose in real human saliva, and it can be an alternative device for the noninvasive detection of glucose. Overall, the outcomes of the EGFET studies demonstrate that the prepared electrodes are well-suited for expeditious detection of glucose levels in saliva.

Nonenzymatic Potentiometric Detection of Ascorbic Acid with Porphyrin/ZnO-Functionalized Laser-Induced Graphene as an Electrode of EGFET Sensors.

Laser-induced graphene (LIG) has emerged as a highly versatile material with significant potential in the development of electrochemical sensors. In this paper, we investigate the use of LIG and LIG functionalized with ZnO and porphyrins-ZnO as the gate electrodes of the extended gate field effect transistors (EGFETs). The resultant sensors exhibit remarkable sensitivity and selectivity, particularly toward ascorbic acid. The intrinsic sensitivity of LIG undergoes a notable enhancement through the incorporation of hybrid organic-inorganic materials. Among the variations tested, the LIG electrode coated with zinc tetraphenylporphyrin-capped ZnO nanoparticles demonstrates superior performance, reaching a limit of detection of approximately 3 nM. Furthermore, the signal ratio for 5 µM ascorbic acid relative to the same concentration of dopamine exceeds 250. The practical applicability of these sensors is demonstrated through the detection of ascorbic acid in real-world samples, specifically in a commercially available food supplement containing l-arginine. Notably, formulations with added vitamin C exhibit signals at least 25 times larger than those without, underscoring the sensors' capability to discern and quantify the presence of ascorbic acid in complex matrices. This research not only highlights the enhanced performance of LIG-based sensors through functionalization but also underscores their potential for practical applications in the analysis of vitamin-rich supplements.

Unprecedented Multifunctionality in Novel Monophase Micro/Nanostructured Ti-Zn Alloy.

It is always challenging to integrate multiple functions into one material system. However, those materials/devices will address society's critical global challenges and technological demands if achieved with innovative design strategies and engineering. Here, one such material with a broader spectrum of desired properties appropriate for seven applications is identified and explored, and a glucose-sensing-triggered energy-storage mechanism is demonstrated. To date, the Titanium (Ti)-Zinc (Zn) binary alloys are investigated only as mixed phases and for a maximum of three applications. In contrast, the novel single phase of structurally stable 50 Ti-50 Zn (Ti0.5 Zn0.5 ) is synthesized and proven suitable for seven emerging applications. Interestingly, it is thermally stable up to 750 °C and possesses excellent mechanical, tribological properties and corrosion resistance. While exceptional biocompatibility is evident even up to a concentration of 500 µg mL-1 , the antibacterial activity against E. coli is also seen. Further, rapid detection and superior selectivity for glucose, along with supercabattery behavior, unambiguously demonstrate that this novel monophase is a remarkable multifunctional material than the existing mixed-phase Ti-Zn compounds. The coin-cell supercapacitor shows outstanding stability up to 30 000 cycles with >100% retention capacity. This allows us to prototype a glucose-sensing-triggered energy-storage-device system for wearable point-of-care diagnostic applications.

Prussian blue analogues of Ni-Co-MoS2 nanozymes with high peroxidase like activity for sensitive detection of glyphosate and copper.

The rational development of efficient nanozymes for the colorimetric detection of targets is still challenging. Herein, Prussian blue analogues of Ni-Co-MoS2 nano boxes were fabricated for colorimetric detection of glyphosate and copper ions owing to its peroxidase like activity. At the sensing system, the Ni-Co-MoS2 nano boxes display high peroxidase activity, which could catalytically oxidize the colourless TMB to blue colour oxTMB. In presence of glyphosate in this sensing system the blue colour is diminished, ascribed to the inhibit the catalytic activity of Ni-Co-MoS2 nano boxes. Concurrently, the addition of copper ion, which result in blue colour was reappear due to the generation of glyphosate-copper complex formation. The Ni-Co-MoS2 nano boxes based colorimetric sensing platform was developed to sensitive detection of glyphosate and copper ions with low detection limit of 3 nM for glyphosate and 3.8 nM for copper. This method also displays satisfactory outcomes from real samples analysis and its good accuracy. Therefore, this work provides a great potential for rapid detection of the targets from the environments.

Hydration effect of selected atmospheric gases with finite water clusters: A quantum chemical investigation towards atmospheric implications.

Water vapor in atmosphere is ubiquitous, and it varies according to geographical locations. Various toxic and non-toxic gases co-exist with water vapor/moisture in the atmosphere. This computational study addresses the fact that how those gases interact with water vapor. We have done quantum chemical density functional theory calculations to probe the interaction of certain gases with a finite number of water molecules in gas phase with various functionals/basis sets. An ensemble of 14 gas molecules comprising various diatomic, triatomic, and polyatomic gases have been chosen for the investigations. The intermolecular interactions are understood from the interaction energy, electrostatic potential, frontier molecular orbitals, energy gap, and natural bond orbital analyses. Furthermore, quantum molecular descriptors such as electronegativity, chemical potential, chemical hardness and electrophilicity index are calculated to have deep insight on chemical nature of the gas molecules. Additionally, we have done implicit solvent modelling using PCM, and the corresponding solvation energies have been calculated. Interestingly, all the calculations and analyses have projected the similar results that Cl2, SO2, and NH3 have very high interaction with the water clusters. To mimic various altitudes (0 km, 5 km and 10 km) in the atmosphere, thermochemistry calculations have been carried out at different temperature and pressure values. The Gibbs free energies of formation suggest that the hydration of Cl2 is higher followed by O2, SO2 and NH3 at all altitudes. Remarkably, it is found that the formation of hydrated clusters of Cl2 and O2 with 4H2O are thermodynamically favourable. On the other hand, SO2 and NH3 requires 5H2O and 3H2O to form thermodynamically favourable clusters. In summary, it is anticipated that this kind of extensive computational studies facilitate to understand the structural, electronic, chemical and thermochemical properties of hydrated atmospheric gases that leads to the formation of prenucleation clusters followed by atmospheric aerosols.

Ferroelectric-semiconductor BaTiO3-Ag2O nanohybrid as an efficient piezo-photocatalytic material.

Piezo-photocatalysis is a new concept of utilizing nanohybrids comprising piezoelectric and photocatalytic materials for enhancement in advanced oxidation process under the presence of light and mechanical energy. In this study, we explored the effectiveness of piezo-photocatalysis via examining their catalytic activity towards the degradation of azo dye (Rhodamine-B) and standard pollutant (Phenol) catalyzed by ferroelectric-semiconductor (BaTiO3-Ag2O) nanohybrids. Further, the enhancement in piezo-photocatalysis has been achieved via persulfate activation and the role of free radicals was examined by quenchers. A plausible mechanism for the improved piezo-photocatalysis of BaTiO3-Ag2O nanohybrid using persulfate activation has been discussed in detail. The removal mechanism of Rhodamine-B has been investigated using analytical techniques such as HPLC and EPR. Our experimental study demonstrated that the combination of piezo-photocatalysis with persulfate activation will provide higher reaction rate which will be beneficial towards the degradation of complex molecular pollutants derived from industrial sectors.

Combinatorial selectivity with an array of phthalocyanines functionalized TiO2/ZnO heterojunction thin film sensors.

The development of electronic noses requires the control of the selectivity pattern of each sensor of the array. Organic chemistry offers a manifold of possibilities to this regard but in many cases the chemical sensitivity is not matched with the response of electronic sensor. The combination of organic and inorganic materials is an approach to transfer the chemical sensitivities of the sensor to the measurable electronic signals. In this paper, this approach is demonstrated with a hybrid material made of phthalocyanines and a bilayer structure of ZnO and TiO2. Results show that the whole spectrum of sensitivity of phthalocyanines results in changes of the resistance of the sensor, and even the adsorption of compounds, such as hexane, which cannot change the resistance of pure phthalocyanine layers, elicits changes of the sensor resistance. Furthermore, since phthalocyanines are optically active, the sensitivity in dark and visible light are different. Thus, operating the sensor in dark and light two different signals per sensors can be extracted. As a consequence, an array of 3 sensors made of different phthalocyanines results in a virtual array of six sensors. The sensor array shows a remarkable selectivity respect to a set of test compounds. Principal component analysis scores plot illustrates that hydrogen bond basicity and dispersion interaction are the dominant mechanisms of interaction.

COVID-19: A review of newly formed viral clades, pathophysiology, therapeutic strategies and current vaccination tasks.

Today, the world population is facing an existential threat by an invisible enemy known as severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) or COVID-19. It is highly contagious and has infected a larger fraction of human population across the globe on various routes of transmission. The detailed knowledge of the SARS-CoV-2 structure and clinical aspects offers an important insight into the evolution of infection, disease progression and helps in executing the different therapies effectively. Herein, we have discussed in detail about the genome structure of SARS-CoV-2 and its role in the proteomic rational spread of different muted species and pathogenesis in infecting the host cells. The mechanisms behind the viral outbreak and its immune response, the availability of existing diagnostics techniques, the treatment efficacy of repurposed drugs and the emerging vaccine trials for the SARS-CoV-2 outbreak also have been highlighted. Furthermore, the possible antiviral effects of various herbal products and their extracted molecules in inhibiting SARS-CoV-2 replication and cellular entry are also reported. Finally, we conclude our opinion on current challenges involved in the drug development, bulk production of drug/vaccines and their storage requirements, logistical procedures and limitations related to dosage trials for larger population.

Tribological Behavior of NiMoAl-Based Self-Lubricating Composites.

The present study focused on the development of NiMoAl-based self-lubricating composites using solid lubricants as the second phase by powder metallurgy. For this, Cr2AlC MAX phase, Cr2AlC-Ag, and MoS2 powders were mixed with the NiMoAl-based matrix and subsequently hot pressed to produce bulk composite samples. The average hardness and wear resistance of the matrix were found to be increased with the addition of MoS2, Cr2AlC MAX phase, and Cr2AlC-Ag powder to the NiMoAl matrix. The addition of Cr2AlC to NiMoAl was more effective in improving the wear resistance than MoS2. The addition of Cr2AlC and Cr2AlC-Ag has increased the hardness by about 75% than that with the addition of NiMoAl alloy. A scanning Kelvin probe system was used to study the surface properties of the tribofilm in detail through work function mapping from the edge area to the wear area (groove). Among all the samples, the one with the addition of Cr2AlC-Ag powder to the NiMoAl matrix possesses the best tribo-mechanical properties. Cr2AlC-Ag composite addition to NiMoAl was found to decrease the wear rate by one-third and to reduce the coefficient of friction by one-fourth, compared to the base NiMoAl alloy. This was attributed to the high-sintered density and formation of strong tribofilms consisting of mixed oxides such as Ag2MoO4 and Al2O3, as confirmed by micro Raman spectra.

Comparative Study on the Preparation and Gas Sensing Properties of Reduced Graphene Oxide/SnO2 Binary Nanocomposite for Detection of Acetone in Exhaled Breath.

Reduced graphene oxide/tin dioxide (RGO/SnO2) binary nanocomposite for acetone sensing performance was successfully studied and applied in exhaled breath detection. The influence of structural characteristics was explored by synthesizing the composite (RGO/SnO2) using the solvothermal method (GS-I) and the hydrothermal method (GS-II) by the chemical route and mechanical mixing, respectively. The nanocomposites characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier transform-infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) revealed that GS-I exhibited better surface area, surface energy and showed enhanced gas response than GS-II at an operating temperature of 200 °C. These sensors exhibited comparable response in humid environment as well, suitable for acetone sensing in exhaled breath that clearly distinguishes between healthy and diabetes subjects. The enhanced response at lower concentrations was attributed to the synergistic effect at the RGO/SnO2 interface. These results indicate that modification in the structural characteristics of RGO/SnO2 nanocomposite enhances the sensing property. Furthermore, it proved to be a promising material for potential application for point-of care, noninvasive diabetes detection.

The influence of film morphology and illumination conditions on the sensitivity of porphyrins-coated ZnO nanorods.

ZnO and porphyrins have complementary properties that make their combination attractive for diverse applications such as photovoltaic and chemical sensing. Among the other features, the organic layer morphology is supposed to influence both the chemical sensitivity and the charge transfer processes. In this paper, we studied the influence of the film morphology on the sensing properties by comparing porphyrins coated ZnO nanorods obtained with two different methods. In the first approach, each porphyrin unit is grafted onto preformed ZnO nanorods by a carboxylic group as linker. The second method is a one-pot procedure, where ZnO nanorods growth occurs in the presence of the water soluble tetrakis-(4-sulfonatophenyl)porphyrin. In both cases the macrocycles share the same Zn-tetraphenylporphyrin core structure, but decorated with different peripheral groups, necessary to comply with the material growth conditions. The adsorption of volatile organic molecules has been monitored measuring the contact potential difference between the sensitive surface and a gold electrode, by means of a Kelvin probe setup. Sensitive signals have been measured both in dark and under visible light. The results show that material preparation affects both the sensitivities to gases and light. A chemometric analysis of four sensors (first and second growth method, measured in dark and in light) shows two main evidences: (a) the interaction between volatile compounds and the sensing layer is largely dominated by non-specific dispersion interaction and (b) the signal of the four sensors becomes rather uncorrelated when the contribution of the dispersion interaction is removed. These results indicate that the differences due to film morphology are enough to differentiate the sensor behaviour, even when the same porphyrin nucleus is used as sensing element. This feature provides an additional degree of freedom for the development of gas sensor arrays.