Nanomaterials-based electrochemical biosensors for diagnosis of COVID-19.

Since the outbreak of corona virus disease 2019 (COVID-19), this pandemic has caused severe death and infection worldwide. Owing to its strong infectivity, long incubation period, and nonspecific symptoms, the early diagnosis is essential to reduce risk of the severe illness. The electrochemical biosensor, as a fast and sensitive technique for quantitative analysis of body fluids, has been widely studied to diagnose different biomarkers caused at different infective stages of COVID-19 virus (SARS-CoV-2). Recently, many reports have proved that nanomaterials with special architectures and size effects can effectively promote the biosensing performance on the COVID-19 diagnosis, there are few comprehensive summary reports yet. Therefore, in this review, we will pay efforts on recent progress of advanced nanomaterials-facilitated electrochemical biosensors for the COVID-19 detections. The process of SARS-CoV-2 infection in humans will be briefly described, as well as summarizing the types of sensors that should be designed for different infection processes. Emphasis will be supplied to various functional nanomaterials which dominate the biosensing performance for comparison, expecting to provide a rational guidance on the material selection of biosensor construction for people. Finally, we will conclude the perspective on the design of superior nanomaterials-based biosensors facing the unknown virus in future.

Swab the Throat as Well as the Nose? The Debate Over the Best Way to Test for SARS-CoV-2.

This Medical News article discusses whether swabbing both the nose and the throat might improve the sensitivity of rapid antigen COVID-19 tests.

An Unusual Retained Choanal Foreign Body: A Possible Complication of COVID-19 Testing With Nasopharyngeal Swab.

Testing for coronavirus disease 2019 is critical in controlling the pandemic all over the world. Diagnosis of severe acute respiratory syndrome coronavirus-2 infection is based on real-time polymerase chain reaction performed on nasopharyngeal swab. If not adequately performed, the viral specimen collection can be painful and lead to complications. We present a complication occurred during a nasopharyngeal swab collection performed in a noncooperative patient where the plastic shaft of the swab fractured during the procedure, resulting in swab tip retention deep into the nasal cavity. The foreign body was found endoscopically, stuck between the nasal septum and the superior turbinate tail at the upper level of the left choana and removed under general anesthesia in a negative pressure operating room with the health care personnel wearing personal protective equipment. Unpleasant complications like the one described can happen when the swab is collected without the necessary knowledge of nasal anatomy or conducted inappropriately, especially in noncooperative patients. Moreover, the design of currently used viral swabs may expose to accidental rupture, with risk of foreign body retention in the nasal cavities. In such cases, diagnosis and treatment are endoscopy-guided procedures performed in an adequate setting to minimize the risk of spreading of the pandemic.

Integration of Multiple Interferometers in Highly Multiplexed Diagnostic KITs to Evaluate Several Biomarkers of COVID-19 in Serum.

In the present work, highly multiplexed diagnostic KITs based on an Interferometric Optical Detection Method (IODM) were developed to evaluate six Coronavirus Disease 2019 (COVID-19)-related biomarkers. These biomarkers of COVID-19 were evaluated in 74 serum samples from severe, moderate, and mild patients with positive polymerase chain reaction (PCR), collected at the end of March 2020 in the Hospital Clínico San Carlos, in Madrid (Spain). The developed multiplexed diagnostic KITs were biofunctionalized to simultaneously measure different types of specific biomarkers involved in COVID-19. Thus, the serum samples were investigated by measuring the total specific Immunoglobulins (sIgT), specific Immunoglobulins G (sIgG), specific Immunoglobulins M (sIgM), specific Immunoglobulins A (sIgA), all of them against SARS-CoV-2, together with two biomarkers involved in inflammatory disorders, Ferritin (FER) and C Reactive Protein (CRP). To assess the results, a Multiple Linear Regression Model (MLRM) was carried out to study the influence of IgGs, IgMs, IgAs, FER, and CRP against the total sIgTs in these serum samples with a goodness of fit of 73.01% (Adjusted R-Squared).

3D-printed simulator for nasopharyngeal swab collection for COVID-19.

OBJECTIVES: Diagnosis of COVID-19 is essential to prevent the spread of SARS-CoV-2. Nasopharyngeal swabs (NPS) remain the gold standard in screening, although associated with false negative results (up to 30%). We developed a 3D simulator of the nasal and pharyngeal cavities for the learning and improvement of NPS collection. PATIENTS AND METHODS: Simulator training sessions were carried out in 11 centers in France. A questionnaire assessing the simulator was administered at the end of the sessions. The study population included both healthcare workers (HCW) and volunteers from the general population. RESULTS: Out of 589 participants, overall satisfaction was scored 9.0 [8.9-9.1] on a scale of 0 to 10 with excellent results in the 16 evaluation items of each category (HCWs and general population, NPS novices and experienced). The simulator was considered very realistic (95%), easy to use (97%), useful to understand the anatomy (89%) and NPS sampling technique (93%). This educational tool was considered essential (93%). Participants felt their future NPS would be more reliable (72%), less painful (70%), easier to perform (88%) and that they would be carried out more serenely (90%). The mean number of NPS conducted on the simulator to feel at ease was two; technical fluency with the simulator can thus be acquired quickly. CONCLUSION: Our simulator, whose 3D printing can be reproduced freely using a permanent open access link, is an essential educational tool to standardize the learning and improvement of NPS collection. It should enhance virus detection and thus contribute to better pandemic control.

Coupling immuno-magnetic capture with LC-MS/MS(MRM) as a sensitive, reliable, and specific assay for SARS-CoV-2 identification from clinical samples.

Recently, numerous diagnostic approaches from different disciplines have been developed for SARS-CoV-2 diagnosis to monitor and control the COVID-19 pandemic. These include MS-based assays, which provide analytical information on viral proteins. However, their sensitivity is limited, estimated to be 5 × 104 PFU/ml in clinical samples. Here, we present a reliable, specific, and rapid method for the identification of SARS-CoV-2 from nasopharyngeal (NP) specimens, which combines virus capture followed by LC-MS/MS(MRM) analysis of unique peptide markers. The capture of SARS-CoV-2 from the challenging matrix, prior to its tryptic digestion, was accomplished by magnetic beads coated with polyclonal IgG-α-SARS-CoV-2 antibodies, enabling sample concentration while significantly reducing background noise interrupting with LC-MS analysis. A sensitive and specific LC-MS/MS(MRM) analysis method was developed for the identification of selected tryptic peptide markers. The combined assay, which resulted in S/N ratio enhancement, achieved an improved sensitivity of more than 10-fold compared with previously described MS methods. The assay was validated in 29 naive NP specimens, 19 samples were spiked with SARS-CoV-2 and 10 were used as negative controls. Finally, the assay was successfully applied to clinical NP samples (n = 26) pre-determined as either positive or negative by RT-qPCR. This work describes for the first time a combined approach for immuno-magnetic viral isolation coupled with MS analysis. This method is highly reliable, specific, and sensitive; thus, it may potentially serve as a complementary assay to RT-qPCR, the gold standard test. This methodology can be applied to other viruses as well.

An Insight Into Detection Pathways/Biosensors of Highly Infectious Coronaviruses.

The outbreak of COVID-19 pandemic and its consequences have inflicted a substantial damage on the world. In this study, it was attempted to review the recent coronaviruses appeared among the human being and their epidemic/pandemic spread throughout the world. Currently, there is an inevitable need for the establishment of a quick and easily available biosensor for tracing COVID-19 in all countries. It has been known that the incubation time of COVID-19 lasts about 14 days and 25% of the infected individuals are asymptomatic. To improve the ability to determine SARS-CoV-2 precisely and reduce the risk of eliciting false-negative results produced by mutating nature of coronaviruses, many researchers have established a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay using mismatch-tolerant molecular beacons as multiplex real-time RT-PCR to distinguish between pathogenic and non-pathogenic strains of coronaviruses. The possible mechanisms and pathways for the detection of coronaviruses by biosensors have been reviewed in this study.

A Tri-Channel Oxide Transistor Concept for the Rapid Detection of Biomolecules Including the SARS-CoV-2 Spike Protein.

Solid-state transistor sensors that can detect biomolecules in real time are highly attractive for emerging bioanalytical applications. However, combining upscalable manufacturing with the required performance remains challenging. Here, an alternative biosensor transistor concept is developed, which relies on a solution-processed In2 O3 /ZnO semiconducting heterojunction featuring a geometrically engineered tri-channel architecture for the rapid, real-time detection of important biomolecules. The sensor combines a high electron mobility channel, attributed to the electronic properties of the In2 O3 /ZnO heterointerface, in close proximity to a sensing surface featuring tethered analyte receptors. The unusual tri-channel design enables strong coupling between the buried electron channel and electrostatic perturbations occurring during receptor-analyte interactions allowing for robust, real-time detection of biomolecules down to attomolar (am) concentrations. The experimental findings are corroborated by extensive device simulations, highlighting the unique advantages of the heterojunction tri-channel design. By functionalizing the surface of the geometrically engineered channel with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody receptors, real-time detection of the SARS-CoV-2 spike S1 protein down to am concentrations is demonstrated in under 2 min in physiological relevant conditions.

Instrução de trabalho para colheita, conservação e transporte de amostras de esfregaço/fluído lesão para diagnóstico de Varíola dos Macacos (Monkeypox) / Work instructions for collecting, preserving and transporting swab samples/lesion fluid for Monkeypox diagnosisWork instructions for collecting, preserving and transporting swab samples/lesion fluid for Monkeypox diagnosis

Para o diagnóstico de varíola dos macacos (Monkeypox), amostras de esfregaço e fluído da lesão são as recomendadas para diagnóstico. Amostras de esfregaço nasofaríngeo, esfregaço orofaríngeo, biopsia, sangue total e soro são amostras complementares às de esfregaço/ fluído da lesão e podem ser colhidas para aumentar a capacidade de detecção. Nesta instrução de trabalho, o foco são amostras de esfregaço/fluído da lesão...

A Portable RT-LAMP/CRISPR Machine for Rapid COVID-19 Screening.

The COVID-19 pandemic has changed people's lives and has brought society to a sudden standstill, with lockdowns and social distancing as the preferred preventative measures. To lift these measurements and reduce society's burden, developing an easy-to-use, rapid, and portable system to detect SARS-CoV-2 is mandatory. To this end, we developed a portable and semi-automated device for SARS-CoV-2 detection based on reverse transcription loop-mediated isothermal amplification followed by a CRISPR/Cas12a reaction. The device contains a heater element mounted on a printed circuit board, a cooler fan, a proportional integral derivative controller to control the temperature, and designated areas for 0.2 mL Eppendorf® PCR tubes. Our system has a limit of detection of 35 copies of the virus per microliter, which is significant and has the capability of being used in crisis centers, mobile laboratories, remote locations, or airports to diagnose individuals infected with SARS-CoV-2. We believe the current methodology that we have implemented in this article is beneficial for the early screening of infectious diseases, in which fast screening with high accuracy is necessary.

Self-collection and pooling of samples as resources-saving strategies for RT-PCR-based SARS-CoV-2 surveillance, the example of travelers in French Polynesia.

In French Polynesia, the first case of SARS-CoV-2 infection was detected on March 10th, 2020, in a resident returning from France. Between March 28th and July 14th, international air traffic was interrupted and local transmission of SARS-CoV-2 was brought under control, with only 62 cases recorded. The main challenge for reopening the air border without requiring travelers to quarantine on arrival was to limit the risk of re-introducing SARS-CoV-2. Specific measures were implemented, including the obligation for all travelers to have a negative RT-PCR test for SARS-CoV-2 carried out within 3 days before departure, and to perform another RT-PCR testing 4 days after arrival. Because of limitation in available medical staff, travelers were provided a kit allowing self-collection of oral and nasal swabs. In addition to increase our testing capacity, self-collected samples from up to 10 travelers were pooled before RNA extraction and RT-PCR testing. When a pool tested positive, RNA extraction and RT-PCR were performed on each individual sample. We report here the results of COVID-19 surveillance (COV-CHECK PORINETIA) conducted between July 15th, 2020, and February 15th, 2021, in travelers using self-collection and pooling approaches. We tested 5,982 pools comprising 59,490 individual samples, and detected 273 (0.46%) travelers positive for SARS-CoV-2. A mean difference of 1.17 Ct (CI 95% 0.93-1.41) was found between positive individual samples and pools (N = 50), probably related to the volume of samples used for RNA extraction (200 µL versus 50 µL, respectively). Retrospective testing of positive samples self-collected from October 20th, 2020, using variants-specific amplification kit and spike gene sequencing, found at least 6 residents infected by the Alpha variant. Self-collection and pooling approaches allowed large-scale screening for SARS-CoV-2 using less human, material and financial resources. Moreover, this strategy allowed detecting the introduction of SARS-CoV-2 variants of concern in French Polynesia.

Clinical Evaluation of In-House-Produced 3D-Printed Nasopharyngeal Swabs for COVID-19 Testing.

3D-printed alternatives to standard flocked swabs were rapidly developed to provide a response to the unprecedented and sudden need for an exponentially growing amount of diagnostic tools to fight the COVID-19 pandemic. In light of the anticipated shortage, a hospital-based 3D-printing platform was implemented in our institution for the production of swabs for nasopharyngeal and oropharyngeal sampling based on the freely available, open-source design provided to the community by University of South Florida's Health Radiology and Northwell Health System teams as a replacement for locally used commercial swabs. Validation of our 3D-printed swabs was performed with a head-to-head diagnostic accuracy study of the 3D-printed "Northwell model" with the cobas PCR Media® swab sample kit. We observed an excellent concordance (total agreement 96.8%, Kappa 0.936) in results obtained with the 3D-printed and flocked swabs, indicating that the in-house 3D-printed swab could be used reliably in the context of a shortage of flocked swabs. To our knowledge, this is the first study to report on autonomous hospital-based production and clinical validation of 3D-printed swabs.

Recent Advances in Novel Lateral Flow Technologies for Detection of COVID-19.

The development of reliable and robust diagnostic tests is one of the most efficient methods to limit the spread of coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). However, most laboratory diagnostics for COVID-19, such as enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR), are expensive, time-consuming, and require highly trained professional operators. On the other hand, the lateral flow immunoassay (LFIA) is a simpler, cheaper device that can be operated by unskilled personnel easily. Unfortunately, the current technique has some limitations, mainly inaccuracy in detection. This review article aims to highlight recent advances in novel lateral flow technologies for detecting SARS-CoV-2 as well as innovative approaches to achieve highly sensitive and specific point-of-care testing. Lastly, we discuss future perspectives on how smartphones and Artificial Intelligence (AI) can be integrated to revolutionize disease detection as well as disease control and surveillance.