COVID-19 electrochemical immunosensor with Ag-MOF: Rapid and high-selectivity nasal swab testing for effective detection.

Early detection of the coronavirus is acknowledged as a crucial measure to mitigate the spread of the pandemic, facilitating timely isolation of infected individuals, and disrupting the transmission chain. In this study, we leveraged the properties of synthesized Ag-MOF, including high porosity and increased flow intensity. Electrochemical techniques such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed to develop an economical and portable sensor with exceptional selectivity for COVID-19 detection. The methodology involves the deposition of Ag-MOF onto the surface of a Glassy Carbon Electrode (GCE), which resulted in a progressive augmentation of electric current. Subsequently, the targeted antibodies were applied, and relevant tests were conducted. The sensor demonstrated the capacity to detect the virus within a linear range of 100 fM to 10 nM, boasting a noteworthy Limit of Detection (LOD) of 60 fM. The entire detection process could be completed in a brief duration of 20 min, exhibiting high levels of accuracy and precision, outperforming comparable techniques in terms of speed and efficacy.

Ti3C2/Ni/Sm-based electrochemical glucose sensor for sweat analysis using bipolar electrochemistry.

An innovative electrochemical sensor is introduced that utilizes bipolar electrochemistry on a paper substrate for detecting glucose in sweat. The sensor employs a three-dimensional porous nanocomposite (MXene/NiSm-LDH) formed by decorating nickel-samarium nanoparticles with double-layer MXene hydroxide. These specially designed electrodes exhibit exceptional electrocatalytic activity during glucose oxidation. The glucose sensing mechanism involves enzyme-free oxidation of the analyte within the sensor cell, achieved by applying an appropriate potential. This leads to the reduction of K3Fe(CN)6 in the reporter cell, and the resulting current serves as the response signal. By optimizing various parameters, the measurement platform enables the accurate determination of sweat glucose concentrations within a linear range of 10 to 200 µM. The limit of detection (LOD) for glucose is 3.6 µM (S/N = 3), indicating a sensitive and reliable detection capability. Real samples were analysed  to validate the sensor's efficiency, and the results obtained were both promising and encouraging.

Unmasking the Electrochemiluminescence Properties of Ternary Mn/Fe/Co Metals Doped Porous g-C3N4 Fiber-like Nanostructure.

Graphitic-phase carbon nitride (g-C3N4) materials have exhibited increasingly remarkable performance as emerging electrochemiluminescence (ECL) emitters, owing to their unique optical and electronic properties; however, the ECL merits of porous g-C3N4 nanofibers doped with ternary metals are not yet explored. Deciphering the ECL properties of trimetal-doped g-C3N4 nanofibers could provide an exquisite pathway for ultrasensitive sensing and imaging with impressive advantages of minimal background signal, great sensitivity, and durability. Herein, we rationally synthesized g-C3N4 nanofibers doped atomically with Mn, Fe, and Co elements (Mn/Fe/Co/g-C3N4) in a one-pot via the protonation in ethanol and annealing process driven by the rolling up mechanism. The ECL performance of g-C3N4 with and without metal dopants was investigated and compared with standard Ru(bpy)32+ in the presence of potassium persulfate (K2S2O8) as the coreactant. Notably, g-C3N4 nanofibers doped with metal ions exhibited an ECL efficiency of 483% that was 4.83 times higher than that of Ru(bpy)32+. Mechanistic investigations unveiled that the g-C3N4 nanofibers possess a large surface area and, as a result, exhibit a reduced interfacial impedance within the porous microstructure. These factors contribute to the acceleration of charge transfer rates and the stabilization of charge carriers and excitons, ultimately facilitating the ECL process. This research endeavor may pave the way for a new hot research area and serves as a powerful tool for elucidating fundamental inquiries of ECL on one-dimensional g-C3N4 nanostructures.

Advancements in wearable technology for monitoring lactate levels using lactate oxidase enzyme and free enzyme as analytical approaches: A review.

Lactate is a metabolite that holds significant importance in human healthcare, biotechnology, and the food industry. The need for lactate monitoring has led to the development of various devices for measuring lactate concentration. Traditional laboratory methods, which involve extracting blood samples through invasive techniques such as needles, are costly, time-consuming, and require in-person sampling. To overcome these limitations, new technologies for lactate monitoring have emerged. Wearable biosensors are a promising approach that offers non-invasiveness, low cost, and short response times. They can be easily attached to the skin and provide continuous monitoring. In this review, we evaluate different types of wearable biosensors for lactate monitoring using lactate oxidase enzyme as biological recognition element and free enzyme systems.

Boosting Electrochemiluminescence Immunoassay Sensitivity via Co-Pt Nanoparticles within a Ti3C2 MXene-Modified Single Electrode Electrochemical System on Raspberry Pi.

Point-of-care testing plays a crucial role in diagnostics within resource-poor areas, necessitating the utilization of portable and user-friendly devices. The adaptation of biosensors for point-of-care applications requires careful considerations, such as miniaturization, cost-effectiveness, and streamlined sample processing. In recent years, the electrochemiluminescence (ECL) immunoassay has gained significant attention due to its visual detection capabilities and ability to facilitate high-throughput analysis. However, the development of a practical and cost-effective ECL device remains a challenging task. This study presents the development of an integrated MXene-modified single-electrode electrochemical system (SEES) for visual and high-throughput ECL immunoassays incorporating a Raspberry Pi system. The SEES was designed by affixing a plastic sticker with multiple perforations onto a single carbon ink screen-printed electrode, which operates based on a resistance-induced potential difference. Leveraging the excellent adsorption and bioaffinity properties of the carbon ink screen-printed electrode, effective immobilization of antibodies was achieved. Furthermore, the incorporation of Co-Pt nanoparticles enhanced the ECL intensity and electron transfer kinetics, enabling the sensitive detection of SARS-CoV-2. The developed system comprised 18 individual reaction cells, allowing for simultaneous analysis while maintaining sample isolation. Impressively, the system achieved a remarkable minimum virus detection limit of 10-14 g mL-1, accompanied by a high R2 value of 0.9798. These findings highlight the promising potential of our developed system for efficient point-of-care testing in resource-limited settings.

Synthesis of cuttlebone/ carbon quantum dots/nickel oxide nanocomposite for visible light photodegradation of malachite green used for environmental remediation.

In recent years, the development of light-driven nanophotocatalysts has focused on efficiently eliminating organic pollutants. In this regard, the present work focuses on the photocatalytic removal of malachite green (MG) dye using cuttlebone powder (CB) modified with carbon quantum dots (CQDs)/nickel oxide (NiO) under visible light irradiation. Various techniques were used to characterize the proposed composite, including X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) images. The optical properties of the synthesized CB/CQDs/NiO were analyzed by UV-VIS visible spectroscopy. Using central composite design (CCD), several effective parameters, including pH, dye concentration, amount of photocatalyst, and temperature degradation efficiency, were optimized to achieve the optimal condition for photocatalytic activity of CB/CQDs/NiO. The Langmuir-Hinshelwood model was employed to model the kinetics of the degradation of the dye, the resulting K being 0.378 min-1. The as synthesized nanocomposites could be efficiently removed from water by applying an external magnetic field. The test results indicate that the prepared CB/CQDs/NiO nanocomposite demonstrates excellent stability after four reaction cycles. Furthermore, the nanocomposite shows excellent photocatalytic activity, reducing 99.7% MGdye concentration within 12 min of visible light exposure.

An enzyme-free Ti3C2/Ni/Sm-LDH-based screen-printed-electrode for real-time sweat detection of glucose.

Here, we report the fabrication of an enzyme-free glucose sensor benefiting from nickel-samarium nanoparticles-decorated MXene layered double hydroxide (MXene/Ni/Sm-LDH). The electrochemical response of the MXene/Ni/Sm-LDH to glucose was studied via cyclic voltammetry (CV). The fabricated electrode has high electrocatalytic activity for glucose oxidation. The voltametric response of the MXene/Ni/Sm-LDH electrode to glucose was investigated by differential pulse voltammetry (DPV) that demonstrated an extended linear range of from 0.001 to 0.1 mM and 0.25-7.5 mM with a detection limit down to 0.24 µM (S/N = 3) and a sensitivity at 1673.54 µA mM-1 cm-2 1519.09 µA mM-1 cm-2 in concentrations of 0.01 mM and 1 mM respectively as well as good repeatability, high stability and applicability for the real sample analysis. Moreover, the as-fabricated sensor was applied to glucose detection in human sweat and showed promising results.

Detection of COVID-19: A Smartphone-Based Machine-Learning-Assisted ECL Immunoassay Approach with the Ability of RT-PCR CT Value Prediction.

The unstoppable spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has severely threatened public health over the past 2 years. The current ubiquitously accepted method for its diagnosis provides sensitive detection of the virus; however, it is relatively time-consuming and costly, not to mention the need for highly skilled personnel. There is a clear need to develop novel computer-based diagnostic tools to provide rapid, cost-efficient, and time-saving detection in places where massive traditional testing is not practical. Here, we develop an electrochemiluminescence (ECL)-based detection system whose results are quantified as reverse transcriptase polymerase chain reaction (RT-PCR) cyclic threshold (CT) values. A concentration-dependent signal is generated upon the introduction of the virus to the electrode and is recorded with a smartphone camera. The ECL images are used to train machine learning algorithms, and a model using artificial neural networks (ANNs) for 45 samples was developed. The model demonstrated more than 90% accuracy in the diagnosis of 50 unknown real samples, detecting up to a CT value of 32 and a limit of detection (LOD) of 10-12 g mL-1 in the testing of artificial samples.

Recent trends and advancements in electrochemiluminescence biosensors for human virus detection.

Researchers are constantly looking to find new techniques of virus detection that are sensitive, cost-effective, and accurate. Additionally, they can be used as a point-of-care (POC) tool due to the fact that the populace is growing at a quick tempo, and epidemics are materializing greater often than ever. Electrochemiluminescence-based (ECL) biosensors for the detection of viruses have become one of the most quickly developing sensors in this field. Thus, we here focus on recent trends and developments of these sensors with regard to virus detection. Also, quantitative analysis of various viruses (e.g., Influenza virus, SARS-CoV-2, HIV, HPV, Hepatitis virus, and Zika virus) with a specific interest in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was introduced from the perspective of the biomarker and the biological receptor immobilized on the ECL-based sensors, such as nucleic acids-based, immunosensors, and other affinity ECL biosensors.

Development of sandwich electrochemiluminescence immunosensor for COVID-19 diagnosis by SARS-CoV-2 spike protein detection based on Au@BSA-luminol nanocomposites.

Coronavirus disease (COVID-19) is a new and highly contagious disease posing a threat to global public health and wreaking havoc around the world. It's caused by the Coronavirus that causes severe acute respiratory syndrome (SARS-CoV-2). In the current pandemic situation, rapid and accurate SARS-CoV-2 diagnosis on a large scale is critical for early-stage diagnosis. Early detection and monitoring of viral infections can aid in controlling and preventing infection in large groups of people. Accordingly, we developed a sensitive and high-throughput sandwich electrochemiluminescence immunosensor based on antigen detection for COVID-19 diagnosis (the spike protein of SARS-CoV-2). For the spike protein of SARS-CoV-2, the ECL biosensor had a linear range of 10 ng mL-1 to 10 µg mL-1 with a limit of detection of 1.93 ng mL-1. The sandwich ECL immunosensor could be used in early clinical diagnosis due to its excellent recovery in detecting SARS-CoV-2, rapid analysis (90 min), and ease of use.

Buried-Gate MWCNT FET-Based Nanobiosensing Device for Real-Time Detection of CRP.

C-reactive protein (CRP), an acute-phase protein synthesized in the liver in response to inflammation, is one of the biomarkers used for the detection of several diseases. Sepsis and cardiovascular diseases are two of the most important diseases for which detection of CRP at very early stages in the clinical range can help avert serious consequences. Here, a CNT-based nanobiosensing system, which is portable and reproducible, is used for label-free, online detection of CRP. The system consists of an aptameric CNT-based field-effect transistor benefiting from a buried gate geometry with Al2O3 as a high dielectric layer and can reflect the pro-cytokine concentration. Test results show that the device responds to CRP changes within 8 min, with a limit of detection as low as 150 pM (0.017 mg L-1). The device was found to have a linear behavior in the range of 0.43-42.86 nM (0.05-5 mg L-1). The selectivity of the device was tested with TNF-α, IL-6, and BSA, to which the nanosensing system showed no significant response compared with CRP. The device showed good stability for 14 days and was completely reproducible during this period. These findings indicate that the proposed portable system is a potential candidate for CRP measurements in the clinical range.

Non-adherence to anti-retroviral medication in Shiraz, 2014: a cross sectional study.

BACKGROUND: Medication adherence is a dynamic and complex behavioral process, which is strongly influenced by personal, social and environmental factors. OBJECTIVES: To determine the prevalence and factors affecting non-adherence to medication among HIV-infected patients. DESIGN: A cross-sectional study. SETTING: Voluntary Counseling and Testing Center (VCT), Shiraz, Fars province, in the South of Iran. PATIENTS: Among HIV-positive patients who received anti-retroviral therapy, 214 adult patients were selected through convenience sampling. Their medication adherence was checked by interview and counting the pills on visits during two months. Clinical and laboratory data were obtained from the patients' records. RESULTS: Non-adherence and adherence groups included 30.4% (65) and 69.6% (149) of the patients, respectively. The mean age of patients was 40.80±7.77 years, and ranged from 20 to 65 years. Majority of cases (65%) were male. A significant relationship was found between non-adherence to medications and the variables of transmission method, marital status, housing status, and CD4, but there was no significant relationship with gender. CONCLUSION: The prevalence of medication adherence was similar to other regions with limited financial resources. To increase patient's medication adherence, they should be exposed to motivational interventions to promote their drug consumption, social and occupational support.