A synthesis of evidence for policy from behavioural science during COVID-19.

Scientific evidence regularly guides policy decisions1, with behavioural science increasingly part of this process2. In April 2020, an influential paper3 proposed 19 policy recommendations ('claims') detailing how evidence from behavioural science could contribute to efforts to reduce impacts and end the COVID-19 pandemic. Here we assess 747 pandemic-related research articles that empirically investigated those claims. We report the scale of evidence and whether evidence supports them to indicate applicability for policymaking. Two independent teams, involving 72 reviewers, found evidence for 18 of 19 claims, with both teams finding evidence supporting 16 (89%) of those 18 claims. The strongest evidence supported claims that anticipated culture, polarization and misinformation would be associated with policy effectiveness. Claims suggesting trusted leaders and positive social norms increased adherence to behavioural interventions also had strong empirical support, as did appealing to social consensus or bipartisan agreement. Targeted language in messaging yielded mixed effects and there were no effects for highlighting individual benefits or protecting others. No available evidence existed to assess any distinct differences in effects between using the terms 'physical distancing' and 'social distancing'. Analysis of 463 papers containing data showed generally large samples; 418 involved human participants with a mean of 16,848 (median of 1,699). That statistical power underscored improved suitability of behavioural science research for informing policy decisions. Furthermore, by implementing a standardized approach to evidence selection and synthesis, we amplify broader implications for advancing scientific evidence in policy formulation and prioritization.

Mask assistance to colorimetric sniffers for detection of Covid-19 disease using exhaled breath metabolites.

According to World Health Organization reports, large numbers of people around the globe have been infected or died for Covid-19 due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Researchers are still trying to find a rapid and accurate diagnostic method for revealing infected people by low viral load with the overriding goal of effective diagnostic management. Monitoring the body metabolic changes is known as an effective and inexpensive approach for the evaluation of the infected people. Here, an optical sniffer is introduced to detect exhaled breath metabolites of patients with Covid-19 (60 samples), healthy humans (55 samples), and cured people (15 samples), providing a unique color pattern for differentiation between the studied samples. The sniffer device is installed on a thin face mask, and directly exposed to the exhaled breath stream. The interactions occurring between the volatile compounds and sensing components such as porphyrazines, modified organic dyes, porphyrins, inorganic complexes, and gold nanoparticles allowing for the change of the color, thus being tracked as the sensor responses. The assay accuracy for the differentiation between patient, healthy and cured samples is calculated to be in the range of 80%-84%. The changes in the color of the sensor have a linear correlation with the disease severity and viral load evaluated by rRT-PCR method. Interestingly, comorbidities such as kidney, lung, and diabetes diseases as well as being a smoker may be diagnosed by the proposed method. As a powerful detection device, the breath sniffer can replace the conventional rapid test kits for medical applications.

Enzymeless voltammetric sensor for simultaneous determination of parathion and paraoxon based on Nd-based metal-organic framework.

The aim of this work is to fabricate a sensitive and novel enzymeless electrochemical sensor for the simultaneous determination of parathion and paraoxon using the Nd-UiO-66@MWCNT nanocomposite. For this purpose, Neodymium (Nd) was introduced into a Universitetet i Oslo (UiO-66) structure to construct Nd-UiO-66 and then, adding multi-walled carbon nanotubes to the Nd-UiO-66 to increase the electrocatalytic activity and surface area of the obtained composite. The Nd-UiO-66@MWCNT has numerous advantages like excellent conductivity, tunable texture, and large surface area and can be used as a distinctive structure for the construction of modified glassy carbon electrode (GCE) to enhance the charge-transfer and the efficiency of electrochemical sensors. This modified electrode showed sensitive and selective determination of paraoxon and parathion over the linear ranges of 0.7-100 and 1-120 nM, with detection limits of 0.04 and 0.07 nM, respectively. The proposed Nd-UiO-66@MWCNT/GCE sensor in this study can be applied in environmental and toxicological laboratories and field tests to detect parathion and paraoxon levels.

Construction and application of a novel electrochemical sensor for trace determination of uranium based on ion-imprinted polymers modified glassy carbon electrode.

In the present work, a novel electrochemical sensor modified glassy carbon electrode with ion-imprinted polymers (IIP-GCE) was applied for uranyl ions (UO22+) determination. Surface modifier was synthesized through precipitation polymerization method, using acrylic acid as a monomer, benzoyl peroxide (BPO) as initiator, and trimethylolpropane triacrylate (TMPTA) as cross-linker. A new uranyl-trans-3-(3-pyridyl) acrylic acid complex was employed, serving as an active and specific site on the synthesized modifier. Next, the synthesized modifier was characterized using X-ray diffraction (XRD), Scanning Electron microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. UO22+ ions were detected using a differential pulse adsorptive anodic stripping voltammetry method. Under the optimized conditions (pH = 8.0, pre-concentration time = 10 min and pre-concentration potential = -0.30 V), the modified electrode exhibited linear behavior in the interval of 1.27-95.49 µg.L-1 with a limit of detection (LOD) of 0.43 µg.L-1. Also, the constructed ion-imprinted sensor showed a successful application for determining UO22+ ions with recovery range of 97.6-101% in real samples.

Disposable Paper-Based Biosensors for the Point-of-Care Detection of Hazardous Contaminations-A Review.

The fast detection of trace amounts of hazardous contaminations can prevent serious damage to the environment. Paper-based sensors offer a new perspective on the world of analytical methods, overcoming previous limitations by fabricating a simple device with valuable benefits such as flexibility, biocompatibility, disposability, biodegradability, easy operation, large surface-to-volume ratio, and cost-effectiveness. Depending on the performance type, the device can be used to analyze the analyte in the liquid or vapor phase. For liquid samples, various structures (including a dipstick, as well as microfluidic and lateral flow) have been constructed. Paper-based 3D sensors are prepared by gluing and folding different layers of a piece of paper, being more user-friendly, due to the combination of several preparation methods, the integration of different sensor elements, and the connection between two methods of detection in a small set. Paper sensors can be used in chromatographic, electrochemical, and colorimetric processes, depending on the type of transducer. Additionally, in recent years, the applicability of these sensors has been investigated in various applications, such as food and water quality, environmental monitoring, disease diagnosis, and medical sciences. Here, we review the development (from 2010 to 2021) of paper methods in the field of the detection and determination of toxic substances.

Electrochemical sandwich-type immunosensor for the detection of PSA based on a trimetallic AgAuPt nanocomposite synthesized using the galvanic replacement reaction.

A sandwich-type electrochemical immunoassay was introduced for the determination of the prostate-specific antigen (PSA) biomarker. A direct and simple galvanic replacement reaction was performed between the Ag framework and metallic salts of tetrachloroauric(iii) acid trihydrate and chloroplatinic acid to produce a trimetallic composite of AgAuPt. The trimetallic composite of AgAuPt was applied to the preparation of the capture layer of the immunoassay for stabilizing the primary Ab at the surface of the prepared composite. The immunoassay detection layer was also prepared using a labeled antibody containing a bimetallic composite of AgPt as a label. The various procedures in the immunoassay fabrication were monitored step by step using cyclic voltammetry and electrochemical impedance spectroscopy. Also, the electrochemical determination of PSA was performed using differential pulse voltammetry in the presence of the ferrocene redox probe and H2O2. Furthermore, the effective parameters in the fabrication of the immunoassay included the drop volume of the AgAuPt trimetallic composite and the incubation time for the immobilization of biomolecules (i.e., Ab1, BSA, PSA, and labeled Ab2), and the concentration of H2O2 were optimized during the determination of PSA. Then, the determination of PSA was performed under optimized conditions. It could be seen that there was a linear relation between the PSA concentration and DPV responses in the concentration range of 50 pg mL-1 to 500 ng mL-1 and the limit of detection (LOD) for the proposed immunoassay was calculated as 17.0 pg mL-1. In the following investigation, the cross-reactivity of the proposed immunoassay was studied in the presence of BSA, CEA, IgG, and human hepatitis surface antigen, in which the results showed a negligible change in the performance of the immunoassay.

Electrochemiluminescent biosensor for ultrasensitive detection of lymphoma at the early stage using CD20 markers as B cell-specific antigens.

Herein, by taking advantage of the special binding of an aptamer to the membrane surface of a B cell and accumulation of the positive charges of a nanocomposite, including luminol-chitosan-platinum nanoparticles (L-Cs-Pt NPs), on the negatively charge of the aptamer phosphate backbone, a sensitive, simple, selective and rapid strategy for the detection of lymphoma cells by a new label-free electrogenerated chemiluminescence (ECL) aptasensor has been introduced. With increasing concentrations of B lymphoma cells, the nanocomposite detaches from the aptamer, leading to a decrease in the ECL of a luminol and H2O2 system. With high loading of luminol and Pt NPs on a chitosan, together with the electrocatalytic effect of Pt NPs, enhanced sensitive detection of cancer cells with a limit of detection of 31 cells/mL was achieved. Step-by-step modification and biosensor response to cancer cells was monitored by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and ECL. The aptasensor exhibited excellent specificity for lymphoma cells vs breast cancer (MCF-7) and human embryonic kidney (HEK293) cell lines as potential interferents. Finally, the performance of the aptasensor in blood samples was assessed against a commercial flow cytometric method. Satisfactory results confirmed the applicability of the proposed biosensing platform.

Electrochemical biosensors for the detection of lung cancer biomarkers: A review.

Cancer is one of the most widespread challenges and important diseases, which has the highest mortality rate. Lung cancer is the most common type of cancer, so that about 25% of all cancer deaths are related to the lung cancer. The lung cancer is classified as two different types with different treatment methodology: the small cell lung carcinoma and nonsmall cell lung carcinoma are two categories of the lung cancer. Since the lung cancer is often in the latent period in its early stages, therefore, early diagnosis of lung cancer has many challenges. Hence, there is a need for sensitive and reliable tools for preclinical diagnosis of lung cancer. Therefore, many detection methods have been employed for early detection of lung cancer. As lung cancer tumors growth in the body, the cancerous cells release numerous DNA, proteins, and metabolites as special biomarkers of the lung cancer. The levels of these biomarkers show the stages of the lung cancer. Therefore, detection of the biomarkers can be used for screening and clinical diagnosis of the lung cancer. There are numerous biomarkers for the lung cancer such as EGFR, CEA, CYFRA 21-1, ENO1, NSE, CA 19-9, CA 125 and VEGF. Nowadays, electrochemical methods are very attractive and useful in the lung cancer detections. So, in this paper, the recent advances and improvements (2010-2018) in the electrochemical detection of the lung cancer biomarkers have been reviewed.

High-performance electrochemical enzyme sensor for organophosphate pesticide detection using modified metal-organic framework sensing platforms.

A practical electrochemical biosensor with high sensitivity was developed for detecting organophosphorus (OP). Initially, Ce metal was introduced into an UiO-66-template to form Ce/UiO-66. Later, graphene oxide (GO), carbon black (CB) and multi-walled carbon nanotubes (MWCNTs) were separately added to Ce/UiO-66 to compare the effect of different carbon-based material types on the performance of the biosensor. Exclusively, Ce/UiO-66/MWCNTs with a Ce (7%) and MWCNT (30%) matrix was found to not only load more acetylcholinesterase (AChE) onto vacant sites but also increase electron transfer and decrease the number of diffusion pathways between the thiocholine and electrode surface. Moreover, the appropriate oxophilicity of Ce coupled with the high surface area and good conductivity of MWCNTs in the UiO-66 structure revealed a high affinity to acetylthiocholine chloride (ATCl) and possible catalysis of the hydrolysis of ATCl with a Michaelis-Menten constant of 0.258 mM. This biosensor, under optimal conditions, demonstrated a rapid and sensitive detection of paraoxon over a wide linear range of 0.01-150 nM, with a low detection limit of 0.004 nM. As a result, the AChE/Ce/UiO-66/MWCNTs/GCE biosensor can be employed in laboratory and field experiments to determine paraoxon levels.

Protein capped Cu nanoclusters-SWCNT nanocomposite as a novel candidate of high performance platform for organophosphates enzymeless biosensor.

A biocompatible nanocomposite including bovine serum albumin (BSA) template Cu nanoclusters (CuNCs@BSA) and single-walled carbon nanotubes (SWCNT) was synthesized to fabricate a highly sensitive electrochemical biosensor for paraoxon as a model of organophosphates. The UV-vis, fluorescence and Fourier transform infrared (FTIR) demonstrated that BSA entrapped in the nanocomposite film have been changed in its secondary structure so that it provided an enzyme like activity attributing to the high electrical conductivity of the entrapped copper nanoclusters. Also, the morphology and structure of prepared nanocomposites were investigated by transmission electronic microscopy (TEM) and scanning electron microscopy (SEM). In the prepared nanocomposite, the CuNCs@BSA found to play as a conductive holder as well as an accumulator of redox active centers on the surface of the electrode, and SWCNT improves the electrocatalytic activity along with conductivity of glassy carbon electrode (GCE) surface. The fabricated biosensor exhibited excellent sensitivity, acceptable stability, fast response, and high electrocatalytic activity toward the reduction of paraoxon. The reduction peak current vs paraoxon concentration was linear over the range 50nM to 0.5µM and 0.5-35µM, with a limit of detection of 12.8nM. Notable electrocatalytic properties of the developed electrode toward paraoxon indicated that the nanocomposite possesses a promising potential to fabricate the third generation enzyme-free electrochemical biosensors, bioelectronics and state-of-the-art biomedical devices in the future.

Nanomolar simultaneous determination of tryptophan and melatonin by a new ionic liquid carbon paste electrode modified with SnO2-Co3O4@rGO nanocomposite.

This work describes the development of a new sensor for simultaneous determination of tryptophan and melatonin. The proposed sensor was an ionic liquid carbon paste electrode modified with reduced graphene oxides decorated with SnO2-Co3O4 nanoparticles. The voltammetric oxidation of the analytes by the proposed sensor confirmed that the electrooxidation process undergoes a two-electron/one-proton reaction for melatonin and a two-electron/two-proton reaction for tryptophan in diffusion-controlled processes. Moreover, based on the excellent electrochemical properties of the modified electrode, a sensitive voltammetric method was used for individual and simultaneous determination of melatonin and tryptophan in the aqueous solutions. Under the optimized experimental conditions, a linear response obtained in the range of 0.02 to 6.00µmolL-1 with detection limits of 4.1 and 3.2nmolL-1 for melatonin and tryptophan, respectively. The prepared sensor possessed accurate and rapid response toward melatonin and tryptophan with a good sensitivity, selectivity, stability, and repeatability. Finally, the applicability of the proposed sensor was verified by evaluation of melatonin and tryptophan in various real samples including human serum and tablet samples.

Composite of Cu metal nanoparticles-multiwall carbon nanotubes-reduced graphene oxide as a novel and high performance platform of the electrochemical sensor for simultaneous determination of nitrite and nitrate.

In the present research, we aimed to fabricate a novel electrochemical sensor based on Cu metal nanoparticles on the multiwall carbon nanotubes-reduced graphene oxide nanosheets (Cu/MWCNT/RGO) for individual and simultaneous determination of nitrite and nitrate ions. The morphology of the prepared nanocomposite on the surface of glassy carbon electrode (GCE) was characterized using various methods including scanning electron microscopy (SEM), atomic force microscopy (AFM), and electrochemical impedance spectroscopy. Under optimal experimental conditions, the modified GCE showed excellent catalytic activity toward the electro-reduction of nitrite and nitrate ions (pH=3.0) with a significant increase in cathodic peak currents in comparison with the unmodified GCE. By square wave voltammetry (SWV) the fabricated sensor demonstrated wide dynamic concentration ranges from 0.1 to 75µM with detection limits (3Sb/m) of 30nM and 20nM method for nitrite and nitrate ions, respectively. Furthermore, the applicability of the proposed modified electrode was demonstrated by measuring the concentration of nitrite and nitrate ions in the tap and mineral waters, sausages, salami, and cheese samples.

Modified fractal iron oxide magnetic nanostructure: A novel and high performance platform for redox protein immobilization, direct electrochemistry and bioelectrocatalysis application.

A novel biosensing platform based on fractal-pattern of iron oxides magnetic nanostructures (FIOMNs) and mixed hemi/ad-micelle of sodium dodecyl sulfate (SDS) was designed for the magnetic immobilization of hemoglobin (Hb) at a screen printed carbon electrode (SPCE). The FIOMNs was successfully synthesized through hydrothermal approach and characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). In order to provide guidelines for the mixed hemi/ad-micelle formation, zeta-potential isotherms were investigated. The construction steps of the biosensor were evaluated by electrochemical impedance spectroscopy, cyclic voltammetry and Fourier transform infrared spectroscopy. Direct electron transfer of Hb incorporated into the biocomposite film was realized with a pair of quasi-reversible redox peak at the formal potential of -0.355V vs. Ag/AgCl attributing to heme Fe(III)/Fe(II) redox couple. The results suggested that synergistic functions regarding to the hyper-branched and multidirectional structure of FIOMNs and the dual interaction ability of mixed hemi/ad-micelle array of SDS molecules not only induce an effective electron transfer between the Hb and the underlying electrode (high heterogeneous electron transfer rate constant of 2.08s(-1)) but also provide powerful and special microenvironment for the adsorption of the redox proteins. Furthermore, the biosensor displayed an excellent performance to the electrocatalytic reduction of H2O2 with a detection limit of 0.48µM and Michaelis-Menten constant (Km) value of 44.2µM. The fabricated biosensor represented the features of sensitivity, disposable design, low sample volume, rapid and simple preparation step, and acceptable anti-interferences, which offer great perspectives for the screen-determination of H2O2 in real samples.