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A hexagonal cobalt oxide nanosheet based enzymeless electrochemical sensor showed an ultra-sensitive response for uric acid with excellent selectivity.

Nanomaterial-based biosensors are a promising fit for portable and field-deployable diagnosis sensor devices due to their mass production, miniaturization, and integration capabilities. However, the fabrication of highly stable and reproducible biosensor devices is challenging. In this work, we grow a vertically oriented architecture of zinc oxide nanorods onto the active working area (i.e., the channel between the source and drain) of a field-effect transistor (FET) using a low-temperature hydrothermal method. The glucose oxidase enzyme was immobilized on the zinc oxide nanorod surface by a physical adsorption method to fabricate the electrolyte-gated FET-based glucose biosensor. The electrical properties of the electrolyte-gated FET biosensor were measured with different glucose concentrations. We found a linear increase in current up to 80 mM glucose concentration with high sensitivity (74.78 μA/mMcm

Context is a critical determinant of the effectiveness of quality improvement programs. We assessed the role of contextual factors in influencing the efforts of 5 diverse quality improvement projects as part of the Pediatric Quality Measure Program (PQMP) directed by the Agency for Health Care Research and Quality.We conducted a mixed methods study of 5 PQMP grantees involving semistructured interviews followed by structured worksheets to identify influential contextual factors. Semistructured interviews and worksheets were completed between August and October 2020. Participants were comprised of PQMP grantee teams (2-4 team members per team for a total of 15 participants). Coding and analysis was based on the Tailored Implementation for Chronic Diseases (TICD) framework.Despite heterogeneity in the process and outcome targets of the PQMP initiatives, professional interactions, incentives and resources, and capacity for organizational change were the domains most commonly identified as influential across the grantees. While social, political, and legal factors was not commonly referenced as an important domain, payer or funder policies (a factor within this domain) was highlighted as one of the most influential factors. Overall, the incentives and resources domain was identified as the most influential.We found that using a determinant framework, such as the TICD, is valuable in facilitating comparisons across heterogeneous projects, allowing us to identify key contextual factors influencing the implementation of pediatric quality measures across a diverse range of clinical topics and settings. Future quality improvement work should account for this and include resources to support infrastructure development in addition to program implementation.

Uric acid (UA) level quantification is crucial for the diagnosis and treatment of cardiovascular, arthritis, renal disorder, and preeclampsia diseases. We report the solvent-assisted synthesis of zinc oxide (ZnO) nanoparticles (NPs) which we used to make a seed layer on a conductive fluorine-doped tin oxide (FTO) electrode. Vertically-arranged ZnO nanorods (NRs) were grown using a hydrothermal method. The ZnO NPs and NRs were characterized in detail, which revealed the smaller sizes (10–15 nm) of the NPs and the vertically-arranged nature of the NRs. Furthermore, a highly sensitive UA biosensor was constructed with vertically-arranged ZnO NRs. The electrochemical characterization of the UA biosensor (Nafion/uricase/ZnO NRs–ZnO NPs/FTO) using differential pulse voltammetry (DPV) demonstrated linearity over a wide UA concentration range (0.01–1.5 mM) with a high sensitivity (345.44 μA mM−1 cm−2) and limit of detection (LOD; 2.5 μM). The biosensor also showed good selectivity, high reproducibility, and enhanced shelf-life. Additionally, practical feasibility was tested in a real (i.e., human blood serum) sample. The boosted UA biosensor performance is attributed to the vertically-arranged ZnO NRs, which immobilize a large amount of enzyme owing to their high surface-to-volume ratio, compared to flat surface-based biosensors. The present strategy, using vertically-arranged ZnO NRs on NP-seeded electrodes, can be extended to fabricate different ZnO NR-based chemical/biosensing devices.

Pure erythroid leukaemia (PEL) is a rare and aggressive form of acute leukaemia whose biology remains poorly characterized. The category of acute erythroid leukaemia was signiûcantly revised in the 2016 revision to the World Health Organization (WHO) classiûcation of myeloid neoplasms. In the previous 2008 WHO classiûcation, acute erythroid leukaemia was categorized into two subtypes: erythroleukaemia and pure erythroid leukaemia (PEL), whereas in the 2016 WHO update, erythroleukaemia was merged into myelodysplastic syndrome and PEL becomes the only type of acute erythroid leukaemia. De novo pure erythroid leukaemia is a disease of adults (median age 68 years), exhibits a striking male predominance, is universally associated with an abnormal karyotype and has an exceedingly poor overall median survival of 1.4 months. Given the limited number of reports of this rare and diagnostically challenging entity, we report clinicopathologic characteristics of a case of PEL, diagnosis was made by the bone marrow morphology and immunophenotyping. J Bangladesh Coll Phys Surg 2021; 39: 266-268

In this study, we report the synthesis of nano-donut shaped nickel oxide (NiO) nanostructures using a simple low-temperature hydrothermal process. The detailed characterizations of nano-donut shaped NiO confirm that the as-synthesized nanostructures are grown in large quantity with relatively uniform morphology. Using the nano-donut shaped NiO nanostructures, the electrochemical based non-enzymatic glucose sensors were fabricated and their catalytic properties towards glucose electro-oxidation were conducted in alkaline media. The sensing results revealed the high sensitivity (904.6 µA mM−1 cm−2) and low detection limit (1.4 µM). Owing to the high glucose sensing performance, the nano-donut shaped NiO nanostructures with a unique two-dimensional morphology and high specific surface area have the potential for electrochemical sensing of other biochemical analytes.

Electrolyte-gated transistor (EGT)-based biosensors are created with nanomaterials to harness the advantages of miniaturization and excellent sensing performance. A cholesterol EGT biosensor based on iron oxide (Fe2O3) nanoparticles decorated ZnO nanorods is proposed here. ZnO nanorods are directly grown on the seeded channel using a hydrothermal method, keeping in mind the stability of nanorods on the channel during biosensor measurements in an electrolyte. Most importantly, ZnO nanorods can be effectively grown and modified with Fe2O3 nanoparticles to enhance stability, surface roughness, and performance. The cholesterol oxidase (ChOx) enzyme is immobilized over Fe2O3 nanoparticles decorated ZnO nanorods for cholesterol detection. With cholesterol addition in buffer solution, the electro-oxidation of cholesterol on enzyme immobilized surface led to increased the biosensor’s current response. The cholesterol EGT biosensor detected cholesterol in wide-linear range (i.e., 0.1 to 60.0 mM) with high sensitivity (37.34 μA mM−1cm−2) compared to conventional electrochemical sensors. Furthermore, we obtained excellent selectivity, fabrication reproducibility, long-term storage stability, and practical applicability in real serum samples. The demonstrated EGT biosensor can be extended with changing enzymes or nanomaterials or hybrid nanomaterials for specific analyte detection.

Developing biosensors with advanced nanomaterial is crucial to enhance the sensing performance of the as-fabricated biosensors. Herein, we engineered copper(II) oxide (CuO) nanofibers using a hydrothermal route in a four-neck flask. The structural and morphological properties of as-engineered CuO nanofibers were analysed using an X-ray diffractometer, field-emission scanning, and transmission electron microscopes. The results indicated, CuO nanofibers bear nanosized diameters and length is in the order of micrometers. These CuO nanofibers were utilized to fabricate non-enzymatic biosensors (Nafion/CuO nanofibers/GCE (glassy carbon electrode)) for enhanced glucose detection and the sensing performance of the biosensors were evaluated using cyclic voltammetry (CV) technique in sodium hydroxide buffer. Employing engineered CuO nanofibers as a non-enzymatic material led fabricated biosensor to achieve high sensitivity of 483.10 μMmM–1cm–2, with the lower detection limit (200 nM) and 0.10–10.85 mM linear detection range. Further, the fabricated biosensor showed good reproducibility, excellent selectivity, cyclic and long-time storage stabilities. This work presents a simple hydrothermal technique to prepare CuO nanofibers in large quantity, demonstrating cost-effective synthesis for non-enzymatic biosensor fabrications and many other applications.

Graphitic carbon nitride, (g-CN/g-C3N4), an oldest material, was extensively used as photocatalyst due to high charge separation and transportation property, tunable band gap, and non-toxicity. Recently, g-CN has been utilized as an electron transport layer, interfacial buffer layer, and for passivation of perovskite layers in solar cell devices. Power conversion efficiency of g-CN-based solar cells has gone beyond 22.13% with device stability of more than 1500 h in dark. Additionally, the enhanced environmental stability of solar cell devices is due to the unique packed two-dimensional (2D) structure of g-CN, which provides protection to the devices against environmental degradation. However, availability of the limited synthesis methods and g-CN thin film formation with varying properties and high surface area, are two major concerns which needs to be further improved. This review covers the different methods of g-CN nanostructure synthesis, thin film formation, and their application in photovoltaic (PV) devices. The potential challenges and perspective of g-CN nanomaterials for solar cells are also included in this review.

The blood glucose concentration is the basis of diabetes mellitus “chronic and metabolic disease” diagnosis. The elevated levels of blood sugar “glucose” lead to many health problems, such as chronic kidney failure, stroke, cardiovascular disease, eyes retina damage, and foot ulcers. Hence, early diagnosis is crucial to prevent and avoid life-threatening complications caused at abnormal glucose levels. In recent, different methods (such as electrochemical, colorimetric, piezoelectric, and thermoelectric based biosensors) have been utilized for glucose concentration detection. Among these methods, the electrochemical based biosensors were extensively employed; however, most of the biosensors were enzyme-based. The enzyme-modified electrodes suffered from some drawbacks, for instance, complicated immobilization procedures, high cost, instability, and low sensitivity. Therefore, it becomes crucial to develop novel electrode nanomaterials that work as electrocatalyst for glucose oxidation and also result in high sensitivity and stability. The performance of nonenzymatic glucose biosensors depends on the morphology of the electrode material. Hence, a variety of nanostructured nanomaterials are utilized to fabricate nonenzymatic biosensors with a high working electrode surface area. To fabricate nonenzymatic biosensors for glucose detection, significant efforts have been made to synthesize nanomaterials and use them as an electrocatalyst, for example, metals, metal oxides, and their hybrid nanostructures16-18. Among different catalysts, nanostructures of copper oxide (CuO) have received considerable interest19, 20. CuO is the best candidate to fabricate electrochemical based nonenzymatic glucose biosensors, as CuO based biosensors directly oxidizes glucose on the working electrode surface. Moreover, CuO nanostructures possess advanced properties, which are beneficial for designing biosensors. Research has been concentrated on the shape/dimensions controlling during synthesis of (nano)materials, which have better structural properties that results in enhanced electrochemical performance due to high specific surface area. Previously, a variety of morphologies of CuO nanomaterials have been produced (i.e. nanoparticles, nanowires, nanowhiskers, nanoneedles, nanorods, nanoshuttles, nanoribbons, and nanotubes) using solution-based approach, sonochemical deposition, vapor phase growth, high temperature synthesis, double-jet precipitation, micro-emulsion synthesis, etc. Among these synthesis methods, hydrothermal method presents an environmentally friendly, simple, cost-effective, high-yield, and low-temperature method to synthesize various CuO nanostructures. Herein, we report hierarchical CuO nanoleaves synthesis in large-quantity by a low-temperature hydrothermal method. Hierarchical CuO nanoleaves were synthesized using a low-temperature (95 °C) hydrothermal method (Fig. 1a). For synthesis, 0.25g Cu(CO2CH3)2·H2O and 0.77g CTAB were added in 40 mL deionized (DI) water. Next, 4 mL of 50 mM NaOH was added in the above solution while stirring. Then, the above solution was poured into a refluxing pot on a heating mantle and refluxed at 95 °C for 5h. Finally, black colored precipitates were washed using methanol and DI water to remove impurities and dried at room temperature. FESEM images and EDS analysis of CuO nanoleaves are shown in Fig. 1b-d. The low- and high-magnification images confirm that the CuO nanostructures prepared bear nanoleaves like morphology, and the nanoleaves are uniformly grown in large quantity. EDS analysis of CuO nanoleaves shows that nanoleaves are made of copper (Cu) and oxide (O) elements only (Fig. 1d, inset). EDS spectra shows an additional peak of Si, which is originating from Si substrate used to spread CuO nanoleaves sample for FESEM and EDS analysis. To fabricate hierarchical CuO nanoleaves based nonenzymatic glucose biosensor; first, the slurry of engineered CuO nanoleaves was prepared after mixing with conducting butyl carbitol acetate binder (8:2 v/v ratio) (Fig. 1a). The prepared slurry (2-6 μL) was cast on cleaned glassy carbon electrode (GCE, 0.071 cm2) and kept for drying. Finally, Nafion (5 μL) was coated on the electrode (CuO nanoleaves/GCE) surface and kept for overnight at 4 °C. The electrochemical behavior of fabricated biosensor towards glucose was analzed with cyclic voltammetry (CV) and amperometry (i-t) techniques. Owing to the high electroactive surface area, hierarchical CuO nanoleaves based nonenzymatic biosensor electrode shows enhanced electrochemical catalytic behavior for glucose electro-oxidation in 100 mM sodium hydroxide (NaOH) electrolyte. The nonenzymatic biosensor displays a high sensitivity (1467.32 mA/(mM cm2)), linear range (0.005-5.89 mM), and detection limit of 12 nM (S/N = 3). Moreover, biosensor displayed good selectivity, reproducibility, repeatability, and stability at room temperature over three-week storage period. Further, as-fabricated nonenzymatic glucose biosensors were employed for practical applications in human serum sample measurements. The obtained data were compared to the commercial biosensor, which demonstrates the practical usability of nonenzymatic glucose biosensors in real sample analysis. Therefore, we believe our engineered CuO nanoleaves based nonenzymatic biosensor can pave the way to detect glucose in low glucose level samples (i.e., saliva, tear, sweat). References: Marunaka, World Journal of diabetes, 6, 125-135 (2015). Ahmad, M. Vaseem, N. Tripathy, Y.-B. Hahn, Anal. Chem,. 85, 10448-10454 (2013). Xiao, Y. Liu, L. Su, D. Zhao, L. Zhao, X. Zhang, Anal. Chem., 91, 14803-14807 (2019). Ahmad, M. Khan, M. R. Khan, N. Tripathy, M. I. R. Khan, P. Mishra, M. A. Syed, Ajit Khosla, Microsyst. Technol., 1-6, (2020). Ahmad, M. Khan, N. Tripathy, M. I. R. Khan, A. Khosla, J. Electrochem. Soci., 167, 107504 (2020). Ahmad, T. Mahmoudi, M.-S. Ahn, Y.-B. Hahn, Biosens. Bioelectron., 100, 312-325, (2018). Ahmad, N. Tripathy, J.-H. Park, Y.-B. Hahn, Chem. Commun., 51, 11968-11971 (2015). Yoon, S. N. Lee, M. K. Shin, H.-W. Kim, H. K. Choi, T. Lee, J.-W. Choi, Biosens. Bioelectron., 140, 111343 (2019). Puttananjegowda, A. Taksi, S. Thomas, J. Electrochem. Soci., 167, 037553 (2020). Figure 1. (a) Schematic representation of CuO nanoleaves synthesis, (b-d) FESEM images and EDS spectra (inset d) of engineered hierarchical CuO nanoleaves. Figure 1

Hydrazine, a highly toxic compound, is used worldwide in industries as a reducing agent for numerous applications. It has a harmful effect on humans and the environment; therefore, advanced analytical techniques are utilized to monitor hydrazine levels to minimize exposure. In this work, we report the fabrication of vertically oriented ZnO nanosheets based solution-gated field-effect transistor (FET) sensor for the low concentration detection of hydrazine. The ZnO nanosheets between source-drain electrodes were encapsulated with Nafion matrix to enhance stability and selectivity during hydrazine detection. The ZnO nanosheets-based solution-gated FET sensor’s sensing properties are compared with and without different concentrations of hydrazine in buffer solution. Conductance of the solution-gated FET hydrazine sensor showed substantial change upon addition of different concentrations of hydrazine. The fabricated hydrazine sensor exhibits high sensitivity (12150 μA μM−1 cm−2) in the linear response range of 5–110 nM. The low detection limit (∼1.2 nM; signal-to-noise (S/N) ratio of 3), high sensitivity, stability, and reproducibility are due to the direct growth of nanosheets that provide the controlled morphology and enhanced surface area. Besides, solution-gated FET hydrazine sensor was successfully applied to detect hydrazine in water samples for practical validation of developed hydrazine sensors.

A non-enzymatic electrocatalyst, nickel oxide (NiO) nanosheets was developed via a facile hydrothermal approach and further characterized in detail. To harness the potential of NiO nanosheets as a potential electrocatalyst, the hydrothermally synthesized nanosheets were fixed onto the sensor working electrode for glucose sensing application. The NiO nanosheets providing abundance active sites for non-enzymatic glucose detection showed sensitive (1618.4 µA/mMcm2) response in the linear range of 0.25-3.75 mM. The excellent electrocatalytic activity of the NiO modified gold working electrode resulted in a low detection limit (2.5 µM). Moreover, the sensor selectively detected glucose in the solution containing common interferants such as cholesterol, dopamine, uric acid and ascorbic acid, further makes it highly suitable for non-enzymatic glucose detection in near-real samples.