Paper-based colorimetric detection of COVID-19 using aptasenor based on biomimetic peroxidase like activity of ChF/ZnO/CNT nano-hybrid.

Corona Virus Disease 2019 (COVID-19) as the infectious disease caused the pandemic disease around the world through infection by SARS-CoV-2 virus. The common diagnosis approach is Quantitative RT-PCR (qRT-PCR) which is time consuming and labor intensive. In the present study a novel colorimetric aptasensor was developed based on intrinsic catalytic activity of chitosan film embedded with ZnO/CNT (ChF/ZnO/CNT) on 3,3',5,5'-tetramethylbenzidine (TMB) substrate. The main nanocomposite platform was constructed and functionalized with specific COVID-19 aptamer. The construction subjected with TMB substrate and H2O2 in the presence of different concentration of COVID-19 virus. Separation of aptamer after binding with virus particles declined the nanozyme activity. Upon addition of virus concentration, the peroxidase like activity of developed platform and colorimetric signals of oxidized TMB decreased gradually. Under optimal conditions the nanozyme could detect the virus in the linear range of 1-500 pg mL and LOD of 0.05 pg mL. Also, a paper-based platform was used for set up the strategy on applicable device. The paper-based strategy showed a linear range between 50 and 500 pg mL with LOD of 8 pg mL. The applied paper based colorimetric strategy showed reliable results for sensitive and selective detection of COVID-19 virus with the cost-effective approach.

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.