Ag-modified CuO cavity arrays as a SERS-electrochemical dual signal platform for thiram detection.

Rapid and sensitive determination of pesticide residues in fruits and vegetables is critical for human health and ecosystems. This paper used an Ag-modified CuO sphere-cavity array (CuO@Ag) electrode as a thiram SERS/electrochemical dual readout detection platform. Numerous Raman "hotspots" generated by uniformly distributed silver nanoparticles, charge transfer at the CuO@Ag interface, and the formation of Ag-thiram complexes contribute to the significant enhancement of this SERS substrate, which results in excellent SERS performance with an enhancement factor up to 1.42 × 106. When using SERS as the readout technique, the linear range of the substrate for thiram detection was 0.05-20 nM with a detection limit (LOD) of up to 0.0067 nM. Meanwhile, a correlation between the value of change in current density and thiram concentration was established due to the formation of stable complexes of thiram with Cu2+ generated at specific potentials. The linear range of electrochemical detection was 0.05-20.0 µM, and the detection limit was 0.0167 µM. The newly devised dual-readout sensor offers notable sensitivity and stability. The two signal readout methods complement each other in terms of linear range and detection limit, making it a convenient tool for assessing thiram residue levels in agro-food. At the same time, the combination of commercially available portable equipment makes on-site monitoring possible.

Association of sleep disorders with asthma: a meta-analysis.

BACKGROUND: Animal experiments and clinical trials have revealed a potential relationship between sleep disorders and asthma. However, the associations between these factors remain unclear. MATERIAL AND METHODS: We searched PubMed, Embase, Web of Science and Cochrane Library databases for eligible studies published before 30 December 2022. Studies investigating the association between sleep disorders (insomnia, poor sleep quality and insufficient sleep time) and asthma were selected. Sleep disorders were assessed using questionnaires, interviews, or medical records. Asthma was diagnosed based on medical history and drug use. The Newcastle-Ottawa Scale and the Agency for Healthcare Research and Quality checklist were employed for quality assessment. We used OR with 95% CI as the effect measures and forest plots to display the results. Heterogeneity was evaluated using I2 statistics and subgroup analyses were performed for bias analysis. Publication bias was evaluated using the funnel plots and Egger's test. RESULTS: Twenty-three studies were included in the primary analysis, which suggested a positive association between sleep disorders and asthma (OR: 1.38, 95% CI 1.10 to 1.74). Subgroup analyses were conducted according to the study design, age, family history of asthma and type of sleep disorders. We did not find any association between sleep disorders and asthma in children aged ˂12 years (OR: 1.13, 95% CI 0.97 to 1.32). The association was insignificant in studies where the family history of asthma was adjusted for (OR: 1.16, 95% CI 0.94 to 1.42). Funnel plot and Egger's test indicated a significant publication bias. CONCLUSION: Sleep disorders are associated with an increased prevalence and incidence of asthma. However, the quality of the evidence was low because of potential biases. PROSPERO REGISTRATION NUMBER: CRD42023391989.

A SERS/electrochemical dual-signal readout immunosensor using highly-ordered Au/Ag bimetallic cavity array as the substrate for simultaneous detection of three ß-adrenergic agonists.

A surface-enhanced Raman scattering (SERS)/electrochemical dual-signal readout immunosensor was developed for simultaneous detection of ß-adrenergic agonists salbutamol (SAL), ractopamine (RAC) and phenylethanolamine A (PA). The highly-ordered gold/silver bimetallic cavity array (BMCA) was prepared by electrodepositing Au/Ag nanoparticles to the interstice of highly ordered close-packed polystyrene templates. After electrochemical and SERS characterization, the BMCA was used as the substrate for constructing SERS/electrochemical dual-signal readout immunosensor. 3,3',5,5'-tetramethylbenzidine (TMB), methylene blue (MB) and Nile blue (NB) were selected as the dual-signal reporters, and hybridization chain reaction (HCR) was used as the signal amplifier. The immunoprobe was prepared by absorption of the antibody (Ab) and constructing HCR system embedded with electro/SERS reporter on Au nanoparticles (NPs). After competitive immuno-reaction between coating antigen and analyte for limited Ab on immunoprobe, the SERS/electrochemical dual-signals on BMCA were measured for quantitatively detecting SAL, RAC and PA simultaneously. SAL, RAC and PA were detected in concentration range of 1 pg mL-1 to 100 ng mL-1 with LOD of 0.8, 0.4, and 1.3 pg mL-1, respectively. The applicability of the proposed immunosensor in spiked pork liver samples was verified by the recovery of 95.0%-108.5% with RSD of 6.9%-10.7%. It was proven that the immunosensor was able to detect multiple ß-adrenergic agonists with high sensitivity, specificity, accuracy and precision. The immunosensor can be used as a platform for the determination of other small molecular compounds in biological, food and environmental analytical fields.

Selective detection of HSO3- in living cells using a pyrroloquinoline structure containing turn-on fluorescent probe.

A turn-on fluorescence probe PQP-1 with a pyrroloquinoline skeleton has been designed and synthesized. Probe PQP-1 showed high sensitivity to HSO3-, low detection limit (16.83 nM), and a wide linear range (50-3000 µM). More importantly, probe PQP-1 could distinguish between HSO3- and SO32-. Furthermore, cell imaging experiments of HSO3- in HeLa cells revealed that probe PQP-1 had potential application value in biological systems.

H2O2/Glucose Sensor Based on a Pyrroloquinoline Skeleton-Containing Molecule Modified Gold Cavity Array Electrode.

H2O2-related metabolites are essential indicators in clinical diagnosis because the accumulation of such reactive oxygen species could cause the risk of cardiovascular disease. Herein, we reported an electrochemical sensor to determine H2O2 and glucose. The pyrroloquinoline skeleton containing molecules (PQT) were used as the electrocatalyst and the gold cavity array (GCA) electrodes as the supporting electrode. The GCA electrode was fabricated by electrodeposition using high-ordered two-dimensional polystyrene spheres as the template. The strong absorbability of iodide ions (I-) displaced adventitious materials from the metal surface and the I- monolayer was subsequently removed by electrochemical oxidation to get a clean electrode surface. PQT molecules were firmly immobilized on the GCA electrode and performed an excellent electrocatalytic effect on H2O2/glucose detection, manifested by a small overpotential and a significantly increased reduction current. A good linear correlation was observed over a wide range of 0.2 µmol/L-1.0 mmol/L with the limit of detection of 0.05 µmol/L. Moreover, the sensor can realize sensitive, accurate, and the highly selective detection of actual samples, proving its application prospect in clinical diagnosis.

Eliminating Stubborn Insulated Deposition by Coordination Effect to Boost Zn Electrode Reversibility in Aqueous Electrolyte.

Aqueous rechargeable zinc-ion batteries (ZIBs) have recently shined in energy storage and transmission, which are due to high safety and low cost. However, the extremely stubborn by-products in the Zn anode severely inhibited the Zn2+ adsorption/desorption and exacerbated the dendrite formation. Herein, we report a facile strategy to eliminate inert Zn4(OH)6SO4·xH2O for the improvement of ZIBs according to the coordination effect by employing ethylenediaminetetraacetic acid-diamine (EDTA-2Na) as a coordination additive in traditional electrolyte. Zn2+ is coordinated with the carboxyl group of the four acetyl carboxyl groups and the N in C-N bonds, forming a new chelating structure, and thus stubborn deposition will be dissolved in the electrolyte. As a result, the discharge capacity of 102 mAh g-1 in the ZnSO4/Li2SO4 with EDTA-2Na electrolyte at a current density of 4 C and a stable cycle life with a capacity of 90.3% after 150 cycles are achieved. It has been concluded that the coordination effect strategy provides a valuable idea for solving the defects of ZIBs.

Metformin in Combination with Malvidin Prevents Progression of Non-Alcoholic Fatty Liver Disease via Improving Lipid and Glucose Metabolisms, and Inhibiting Inflammation in Type 2 Diabetes Rats.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is one of the primary causes of chronic liver disease and is closely linked to insulin resistance, type 2 diabetes mellitus (T2DM), and dyslipidemia. However, no effective drug therapies have been approved to treat this disease. The present research aimed to evaluate the therapeutic effects of the combination of oral hypoglycemic drug metformin (MET) and a natural product malvidin (MAL) on hepatic damage in HFD/STZ-induced diabetic rats. METHODS: Sprague-Dawley rats were divided into five groups: normal control group (NC), diabetic control group (DC), DC+MET group, DC+MAL group, and DC+MET+MAL group and treated for eight weeks. Blood and liver tissue samples were collected for metabolic parameters, histological, and RT-qPCR analysis. RESULTS: Our findings indicated that hyperglycemia, insulin resistance, hyperlipidemia, and non-alcoholic fatty liver disease (NAFLD) in diabetic rats were alleviated after oral treatment with MET and MAL, particularly their combination therapy. Besides, the expression of SREBP-1c, ACC, FAS, IL-6, IL-8, and NF-κB mRNA was down-regulated by MET+MAL, and the expression of PPARα, CPT1, and LPL was up-regulated by MET+MAL. CONCLUSION: The evidence of this research indicated that the combination therapy may represent an efficient strategy against NAFLD in T2DM rats via improving lipid and glucose metabolisms, and inhibiting inflammation.

A close-up on COVID-19 and cardiovascular diseases.

AIMS: To analyze the potential mechanism of cardiovascular dysfunctions induced by Coronavirus Disease 2019 (COVID-19) and to evaluate more effective therapeutic pathways for patients with cardiovascular diseases. DATA SYNTHESIS: COVID-19 mainly invades the lungs, causing its serious damage. Studies found that COVID-19 induced the renin-angiotensin system imbalance, inflammatory storm, hypoxemia, stress response, and so on; all contributed to hypertension and serious myocardial damage in the process of virus pathogenesis, even increasing mortality in COVID-19 patients. CONCLUSION: In the process of management of COVID-19 infections, close attention should be paid on both lung and cardiovascular damage, especially on those with only symptoms of cardiovascular diseases. Early identification, timely and effective treatments, and maintenance of hemodynamics and electrophysiological stability are of great significance on effective treatment and long-term prognosis.

NBD-BPEA regulates Zn2+- or Cu2+-induced Aß40 aggregation and cytotoxicity.

Abnormal interaction of amyloid-ß peptide (Aß) and metal ions is proved to be related to the etiology of Alzheimer's disease (AD). Using metal chelators to reverse metal-triggered Aß aggregation has become one of the potential therapies for AD. In our work, the effect of metal chelator, NBD-BPEA, on Zn2+- or Cu2+-mediated Aß40 aggregation and neurotoxicity has been systematically studied. NBD-BPEA exhibits the capability to inhibit the metal-mediated Aß40 aggregation and disassemble performed Aß40 aggregates. It also prevents the formation of the ß-sheet structure and promotes the reversion of the ß-sheet to the normal random coil conformation. Moreover, it can alleviate Zn2+- or Cu2+-Aß40-induced neurotoxicity, suppress the intracellular ROS and protect against cell apoptosis. These preliminary findings indicate that NBD-BPEA has promising perspective of application in the treatment of AD, and therefore deserve further investigation as potential anti-AD agents.

Electrochemical detection of carcinoembryonic antigen.

In this work, a sandwich-type electrochemical immunosensor for carcinoembryonic antigen (CEA) detection has been constructed and tested. Unlike many other sensors using external electrochemical species in the electrolyte to generate an electrochemical signal, a ferrocene derivative has been integrated into the design of the sensor to provide an internal reporting system, allowing detection of CEA in buffers and biological samples. Gold nanoparticles, which have been used to increase the conductivity of sensing surfaces, also carry immobilized secondary anti-CEA and a ferrocene derivative. The shelf life testing of the sensor shows good performance after storage for 4 weeks. The sensor has been calibrated against different concentration of the target protein using square wave voltammetry. The calibration curve has been obtained in the range of 0.05-20ngmL-1, and the detection limit for CEA is ~ 0.01ngmL-1. The capability of the immunosensor has been verified by performing detection of CEA in human serum samples.

Two macrocyclic polyamines as modulators of metal-mediated Aß40 aggregation.

Dysfunctional interactions of amyloid-ß (Aß) with Zn and Cu ions are proved to be related to the etiology of Alzheimer's disease (AD). Disruption of these metal-Aß interactions using metal chelators holds considerable promise as a therapeutic strategy to combat this incurable disease. Herein, we report that two cyclam derivatives (L1 and L2) are capable of modulating Zn(2+)/Cu(2+)-mediated Aß40 aggregation, reactive oxygen species (ROS) production, and neurotoxicity. These chelators were found to inhibit the metal-induced Aß40 aggregation, dissociate metal-Aß40 aggregates and restore the metal-induced ß-sheet structure of Aß40 to its random coil conformation, as observed by BCA protein assay, thioflavin T fluorescence and circular dichroism spectroscopy. Moreover, preliminary investigation of SH-SY5Y cells indicates that L1 and L2 can diminish the neurotoxicity of metal-Aß40 species, control metal-Aß40-triggered ROS production and protect cells against apoptosis. These observations warrant the further investigations of L1 and L2 as potential anti-AD agents.

Detection of dopamine on a mercapto-terminated hexanuclear Fe(III) cluster modified gold electrode.

In this study, a novel mercapto-terminated hexanuclear iron(III) cluster [Fe6O2(OH)2(O2CC6H4SCH3)10(hep)2]·CH3CN·CH2Cl2 [hep=2-(2-hydroxyethyl) pyridine] (Fe6) modified Au electrode was fabricated, having highly sensitive dopamine (DA) detection capabilities. In such Fe6 molecules, 10 thiomethyl groups are located at the periphery of the cluster, which enable the Fe6 molecules to self-assemble onto the surface of Au electrodes through the formation of Au-S bonds. The as-prepared Fe6-modified Au electrode (Au/Fe6) exhibits excellent electrocatalytic activity for the oxidation of dopamine (DA) in PBS with a diffusion coefficient of 3.12×10(-5) cm(2)/s. Using the square wave voltammetry (SWV) technique, the calibration curve for DA determination was obtained in the range of 0.2 to 30 µM, and the detection limit for DA was ~0.07 µM. Furthermore, the modified electrode can accurately separate the DA signal from the interfering effect of uric acid (UA), thus providing simultaneous detection of DA and UA in their binary mixtures. This electrode can be reliably used to assay DA in its real drug composition.

Using a silver-enhanced microarray sandwich structure to improve SERS sensitivity for protein detection.

A simple and sensitive method, based on surface-enhanced Raman scattering (SERS), for immunoassay and label-free protein detection is reported. A series of bowl-shaped silver cavity arrays were fabricated by electrodeposition using a self-assembled polystyrene spheres template. The reflection spectra of these cavity arrays were recorded as a function of film thickness, and then correlated with SERS enhancement using sodium thiophenolate as the probe molecule. The results reveal that SERS enhancement can be maximized when the frequency of both the incident laser and the Raman scattering approach the frequency of the localized surface plasmon resonance. The optimized array was then used as the bottom layer of a silver nanoparticle-protein-bowl-shaped silver cavity array sandwich. The second layer of silver was introduced by the interactions between the proteins in the middle layer of the sandwich architecture and silver nanoparticles. Human IgG bound to the surface of this microcavity array can retain its recognition function. With the Raman reporter molecules labeled on the antibody, a detection limit down to 0.1 ng mL(-1) for human IgG is easily achieved. Furthermore, the SERS spectra of label-free proteins (catalase, cytochrome C, avidin and lysozyme) from the assembled sandwich have excellent reproducibility and high quality. The results reveal that the proposed approach has potential for use in qualitative and quantitative detection of biomolecules.

[Fabrication of two dimensional silver cavity array and its application in SERS detection].

The highly ordered two dimensional micro-/nano-sized silver cavity was fabricated by galvanostatic multistep method using ordered arrays of close-packed 700 nm diameter polystyrene spheres as templates. The morphology and the surface plasmon resonance of this silver cavity array were characterized by scanning electron microscope and reflectance UV-Vis spectra, and surface-enhanced Raman scattering (SERS) spectra of p-aminothiophenol (PATP) and Rhodamine 6G (R6G) on as-prepared substrate were also studied. The results show that: the depth of cavities can be easily regulated through varying the parameters of the electrochemical deposition. As SERS substrates for the detection of PATP molecules, the two dimensional Ag cavity arrays exhibit excellent performance and the enhancement factors can be as high as the 10(7) order. In addition to the high-intensity enhancement, it is also found that the SERS spectra are highly reproducible on this Ag cavity arrays. The relative standard deviation of the peak intensity of PATP molecules at 1 077 cm(-1) was calculated to be 8.4%. The as-prepated substrate can be used for the quantitative detection of R6G, and the detection limit reaches as low as 0.1 ng x mL(-1).

Hydrogen peroxide biosensor based on microperoxidase-11 immobilized in a silica cavity array electrode.

Hydrogen peroxide biosensor based on the silica cavity array modified indium-doped tin oxide (ITO) electrode was constructed. An array of silica microcavities was fabricated by electrodeposition using the assembled polystyrene particles as template. Due to the resistance gradient of the silica cavity structure, the silica cavity exhibits a confinement effect on the electrochemical reactions, making the electrode function as an array of "soft" microelectrodes. The covalently immobilized microperoxidase-11(MP-11) inside these SiO2 cavities can keep its physiological activities, the electron transfer between the MP-11 and electrode was investigated through electrochemical method. The cyclic voltammetric curve shows a quasi-reversible electrochemical redox behavior with a pair of well-defined redox peaks, the cathodic and anodic peaks are located at -0.26 and -0.15V. Furthermore, the modified electrode exhibits high electrocatalytic activity toward the reduction of hydrogen peroxide and also shows good analytical performance for the amperometric detection of H2O2 with a linear range from 2×10(-6) to 6×10(-4)M. The good reproducibility and long-term stability of this novel electrode not only offer an opportunity for the detection of H2O2 in low concentration, but also provide a platform to construct various biosensors based on many other enzymes.

Fabrication of a bowl-shaped silver cavity substrate for SERS-based immunoassay.

In this study, a metal sandwich substrate bridged by an immunocomplex has been created for a surface enhanced Raman scattering (SERS)-based immunoassay. The bottom bowl-shaped silver cavity thin film layer was prepared by electrodeposition using a closely packed monolayer of 700 nm diameter polystyrene spheres as a template. The reflection spectra of the films were recorded as a function of film thickness, and then correlated with SERS enhancement using p-aminothiophenol as the probe molecule. The results demonstrate that SERS enhancement can be maximized when both the frequency of the incident laser and Raman scattering approach the resonance frequency of the localized surface plasmon resonance, providing a guideline for the fabrication and further application of these nanocavity arrays. The second layer of silver was introduced by the interactions between the immunocomplexes in the middle layer of the sandwich architecture and the silver nanoparticles. The proposed structure was used to perform the SERS-based immunoassay. The labeled protein can be detected over a wide concentration range and the detection limit of TRITC and Atto610 labeled proteins were 50 and 5 pg mL(-1), respectively. The results demonstrate that the new SERS substrate is suitable for the quantitative identification of biomolecules.