Trends in electroanalytical assays for COVID-19 diagnosis

The use of electrochemical biosensors is highlighted for SARS-CoV-2 detection and COVID-19 diagnosis. In a brief description of virus structure, fundamental features of proteins and nucleic acid are approached for a comprehensive strategy over biosensor designs. Relevant works are described and related to specific structural proteins used as viral biomarkers. Furthermore, the challenges and perspectives are pointed to the evolution of electroanalysis and the establishment of methods comparable to the gold standard, RT-PCR. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023. All rights reserved.

GlycoEVLR: Glycosylated extracellular vesicle-like receptors for targeting and sensing viral antigen

Biosensors are rapid and portable detection devices with great potential for the instant screening of infectious diseases. Receptors are the critical element of biosensors. They determine the specificity, sensitivity and stability. However, current receptors are mainly limited to antibodies and aptamers. Herein, we developed a glycosylated extracellular vesicle-like receptor (GlycoEVLR) for the rapid detection of virus antigens, specifically using SARS-CoV-2 as a model. The human angiotensin-converting enzyme 2 (ACE2)-overexpressed and heparin-functionalized HEK-293T cell membrane-cloaked Fe3O4 nanoparticles (NPs) were prepared as functionalizing GlycoEVLR. They were characterized as spherical core–shell structures with a diameter of around 100 nm, which were perfectly comparable to natural extracellular vesicles. Binding affinities between GlycoEVLR and spike1 (S1) antigen were demonstrated using surface plasmon resonance (SPR). The GlycoEVLR was fixed on magnetic electrodes to construct electrochemical biosensors. Using electrochemical impedance spectroscopy (EIS) as a measurement technique, the S1 antigen was detected down to 1 pg/mL within 20 min and showed a good linearity range from 1 pg/mL to 1 ng/mL. Also, the GlycoEVLR-based electrochemical biosensors showed excellent antifouling performance and stability. Overall, our work provides a useful methodology for developing extracellular vesicle-like receptors for biosensors. Combining the inherit natural receptor proteins and antifouling lipids from the host cells with engineered glycan motifs to target and sense viral antigens will open a newavenue for biosensors.

Functional Nanomaterials Enhancing Electrochemical Biosensors as Smart Tools for Detecting Infectious Viral Diseases.

Electrochemical biosensors are known as analytical tools, guaranteeing rapid and on-site results in medical diagnostics, food safety, environmental protection, and life sciences research. Current research focuses on developing sensors for specific targets and addresses challenges to be solved before their commercialization. These challenges typically include the lowering of the limit of detection, the widening of the linear concentration range, the analysis of real samples in a real environment and the comparison with a standard validation method. Nowadays, functional nanomaterials are designed and applied in electrochemical biosensing to support all these challenges. This review will address the integration of functional nanomaterials in the development of electrochemical biosensors for the rapid diagnosis of viral infections, such as COVID-19, middle east respiratory syndrome (MERS), influenza, hepatitis, human immunodeficiency virus (HIV), and dengue, among others. The role and relevance of the nanomaterial, the type of biosensor, and the electrochemical technique adopted will be discussed. Finally, the critical issues in applying laboratory research to the analysis of real samples, future perspectives, and commercialization aspects of electrochemical biosensors for virus detection will be analyzed.

Strategies for the Voltammetric Detection of Loop-Mediated Isothermal Amplification.

Loop-mediated isothermal amplification (LAMP) is rapidly developing into an important tool for the point-of-use detection of pathogens for both clinical and environmental samples, largely due to its sensitivity, rapidity, and adaptability to portable devices. Many methods are used to monitor LAMP, but not all are amenable to point-of-use applications. Common methods such as fluorescence often require bulky equipment, whereas colorimetric and turbidimetric methods can lack sensitivity. Electrochemical biosensors are becoming increasingly important for these applications due to their potential for low cost, high sensitivity, and capacity for miniaturization into integrated devices. This review provides an overview of the use of voltammetric sensors for monitoring LAMP, with a specific focus on how electroactive species are used to interface between the biochemical products of the LAMP reaction and the voltammetric sensor. Various strategies for the voltammetric detection of DNA amplicons as well as pyrophosphate and protons released during LAMP are presented, ranging from direct DNA binding by electroactive species to the creative use of pyrophosphate-detecting aptamers and pH-sensitive oligonucleotide structures. Hurdles for adapting these devices to point-of-use applications are also discussed.

Customizable Fabrication Process for Flexible Carbon-Based Electrochemical Biosensors

In recent research, 3D printing has become a powerful technique and has been applied in the last few years to carbon-based materials. A new generation of 3D-printed electrodes, more affordable and easier to obtain due to rapid prototyping techniques, has emerged. We propose a customizable fabrication process for flexible (and rigid) carbon-based biosensors, from biosensor design to printable conductive inks. The electrochemical biosensors were obtained on a 50 µm Kapton® (polyimide) substrate and transferred to a 500 µm PDMS substrate, using a 3D-extrusion-based printing method. The main features of our fabrication process consist of short-time customization implementation, fast small-to-medium batch production, ease of electrochemical spectroscopy measurements, and very good resolution for an extrusion-based printing method (100 µm). The sensors were designed for future integration into a smart wound dressing for wound monitoring and other biomedical applications. We increased their sensibility with electro-deposited gold nanoparticles. To assess the biosensors' functionality, we performed surface functionalization with specific anti-N-protein antibodies for SARS-CoV 2 virus, with promising preliminary results.

Functional Nanomaterials for Electrochemical SRAS-CoV-2 Biosensors: a Review

The pandemic outbreak of COVID-19 has posed a threat to public health globally, and rapid and accurate identification of the viruses is crucial for controlling COVID-19. In recent years, nanomaterial-based electrochemical sensing techniques hold immense potential for molecular diagnosis with high sensitivity and specificity. In this review, we briefly introduced the structural characteristics and routine detection methods of SARS-CoV-2, then summarized the associated properties and mechanisms of the electrochemical biosensing methods. On the above basis, the research progress of electrochemical biosensors based on gold nanomaterials, oxide nanomaterials, carbon-based nanomaterials and other nanomaterials for rapid and accurate detection of virus were reviewed. Finally, the future applications of nanomaterial-based biosensors for biomolecular diagnostics were pointed out. © 2023 Science Press. All rights reserved.

Functional Nanomaterials for Electrochemical SRAS-CoV-2 Biosensors: a Review

The pandemic outbreak of COVID-19 has posed a threat to public health globally, and rapid and accurate identification of the viruses is crucial for controlling COVID-19. In recent years, nanomaterial-based electrochemical sensing techniques hold immense potential for molecular diagnosis with high sensitivity and specificity. In this review, we briefly introduced the structural characteristics and routine detection methods of SARS-CoV-2, then summarized the associated properties and mechanisms of the electrochemical biosensing methods. On the above basis, the research progress of electrochemical biosensors based on gold nanomaterials, oxide nanomaterials, carbon-based nanomaterials and other nanomaterials for rapid and accurate detection of virus were reviewed. Finally, the future applications of nanomaterial-based biosensors for biomolecular diagnostics were pointed out. © 2023 Science Press. All rights reserved.

The role of biosensors in coronavirus disease-2019 outbreak.

Herein, we have summarized and argued about biomarkers and indicators used for the detection of severe acute respiratory syndrome coronavirus 2. Antibody detection methods are not considered suitable to screen individuals at early stages and asymptomatic cases. The diagnosis of coronavirus disease 2019 using biomarkers and indicators at point-of-care level is much crucial. Therefore, it is urgently needed to develop rapid and sensitive detection methods which can target antigens. We have critically elaborated key role of biosensors to cope the outbreak situation. In this review, the importance of biosensors including electrochemical, surface enhanced Raman scattering, field-effect transistor, and surface plasmon resonance biosensors in the detection of severe acute respiratory syndrome coronavirus 2 has been underscored. Finally, we have outlined pros and cons of diagnostic approaches and future directions.

Advances in the screening of antimicrobial compounds using electrochemical biosensors: is there room for nanomaterials?

The abusive use of antimicrobial compounds and the associated appearance of antimicrobial resistant strains are a major threat to human health. An improved antimicrobial administration involves a faster diagnosis and detection of resistances. Antimicrobial susceptibility testing (AST) are the reference techniques for this purpose, relying mainly in the use of culture techniques. The long time required for analysis and the lack of reproducibility of these techniques have fostered the development of high-throughput AST methods, including electrochemical biosensors. In this review, recent electrochemical methods used in AST have been revised, with particular attention on those used for the evaluation of new drug candidates. The role of nanomaterials in these biosensing platforms has also been questioned, inferring that it is of minor importance compared to other applications.

A portable, low-cost and high-throughput electrochemical impedance spectroscopy device for point-of-care biomarker detection

This paper presents a portable, fast and accurate electrochemical impedance spectroscopy (EIS) device with 8-well interdigitated electrode chips for biomarker detection. The design adopts low crest factor multisine signal synthesis at low frequencies (<1 kHz) and single-tone signals at high frequencies (>1 kHz), which significantly increases measurement speed without sacrificing accuracy. In addition, the low excitation amplitude of 10 mV preserves impedance linearity and protects the biosamples. The system achieved an average magnitude accuracy error of 0.30% in the frequency range of interest and it requires only 0.46 s to scan 28 frequency points from 10 Hz to 1 MHz. Experiments were conducted to test the capability to detect antibodies against SARS-CoV-2. Gold nanoparticles bound with protein G (GNP-G) were employed as the conjugated secondary antibody probe to detect anti-SARS-CoV-2 IgG in serum. A highly statistical significance (p = 7×10−6) could be found in the impedance data at 10 kHz. The impedance magnitude alteration caused by the GNP-G of the positive and negative groups were 27.2%±13.6% and 4.1%±1.7%, respectively. The results imply that the proposed system enables rapid COVID-19 antibody biomarker detection. Moreover, the EIS system and GNPs have the potential to be modified to detect other biomarkers. © 2022 The Author(s)

Electrochemical Biosensors Based on Carbon Nanomaterials for Diagnosis of Human Respiratory Diseases.

In recent years, respiratory diseases have increasingly become a global concern, largely due to the outbreak of Coronavirus Disease 2019 (COVID-19). This inevitably causes great attention to be given to the development of highly efficient and minimal or non-invasive methods for the diagnosis of respiratory diseases. And electrochemical biosensors based on carbon nanomaterials show great potential in fulfilling the requirement, not only because of the superior performance of electrochemical analysis, but also given the excellent properties of the carbon nanomaterials. In this paper, we review the most recent advances in research, development and applications of electrochemical biosensors based on the use of carbon nanomaterials for diagnosis of human respiratory diseases in the last 10 years. We first briefly introduce the characteristics of several common human respiratory diseases, including influenza, COVID-19, pulmonary fibrosis, tuberculosis and lung cancer. Then, we describe the working principles and fabrication of various electrochemical biosensors based on carbon nanomaterials used for diagnosis of these respiratory diseases. Finally, we summarize the advantages, challenges, and future perspectives for the currently available electrochemical biosensors based on carbon nanomaterials for detecting human respiratory diseases.

Rapid SARS-CoV-2 S-protein Detection using Nanostructured Electrochemical Biosensor

We have developed a new type of testing strategy based on the electrochemical biosensing aspect for rapid and portable detection of SARS-CoV-2. The detection platform is based on a highly conductive matrix (fabricated polystyrene/polyaniline-Au nanocomposite) enabling immobilization of representative receptor elements (antibodies) that are specific to the target, i.e., SARS-CoV-2 spike (S)-protein. The concept of a detection system is to translate specific covalent interaction between antibodies and its corresponding binding viral S-protein, into a measurable, concentration-dependent electrochemical signal. The biosensor is able to monitor the electrochemical response in PBS, without using hazardous [Fe(CN)]63-/4- redox couple. By creating an electrochemical readout (CV, EIS, and DPV), data enables qualitative and quantitative analysis. Additionally, it exploits outstanding conductivity and biocompatibility, thus resulting in high analytical sensitivity and a low detection limit of 15.6μ g/mL, which is within the physiologically relevant concentration range. Thus, the proposed feasible design of the biosensor platform represents an excellent starting point for practical and low-cost testing of asymptomatic patients or people before symptom onset. © 2022 IEEE.

Metal oxide nanocomposite-based electrochemical biosensing studies

The growing world population is facing challenges like energy crisis, environmental sustainability, global public health problems, etc. Among these, the resolution of public health issue is of prime importance for the people to live happily and enjoy each moment of their life. However, various diseases such as diabetes mellitus, HIV, cancer, Alzheimer's disease, stroke, and other neurological diseases have no permanent cure yet. New life-threatening diseases and viruses like COVID-19, Zika, Ebola, SARS, MERS and H1N1 etc. are affecting humans, which lead to loss of life. through Early diagnosis, proper medical treatment and accessible health monitoring systems can be both life saving and cost saving for the patients. Particularly, biosensing protocols in connection to early diagnosis as well as health monitoring have placed a significant importance in biomedical sector. In the current context where population and bio-testing capacity have a remarkable gap, the effect of prompt and specific detection of target molecules is also important from the point of view of biosensor field. Hence, the development of biomedical sensors having the features such as easy to handle, cost effective, short time span for analysis, multianalyte sensing, sophisticated digital display, etc. are the need of hour. For example, glucometer is a well-known example of biosensor device;glucometer measures the sugar content present in blood sample. Similarly, various sensors such as glucowatch, tooth enamel biosensor, colorimetric sweat biosensor, etc. have wide application in biosensing for the analysis of different biomolecules. © 2022 Elsevier Inc. All rights reserved.

Innovations and Challenges in Electroanalytical Tools for Rapid Biosurveillance of SARS‐CoV‐2 (Adv. Mater. Technol. 12/2022)

Coronavirus disease 2019, biosurveillance, electrochemical biosensors, rapid test, Internet of Things The recent electrochemical biosensors are promising electroanalytical tools, pivotal for developing a biosurveillance ecosystem for rapid, point-of-care (POC), and internet-of-things-(IoT)-integrated detection of SARS-CoV-2, and possibly, other infectious pathogens. Keywords: coronavirus disease 2019;biosurveillance;electrochemical biosensors;rapid test;Internet of Things EN coronavirus disease 2019 biosurveillance electrochemical biosensors rapid test Internet of Things 1 1 1 12/20/22 20221201 NES 221201 B Electrochemical Biosensors b One of the first steps to combat a highly transmittable infectious disease is to detect it locally, before it spreads globally. [Extracted from the article]

SARS-CoV-2 Virus Detection Via a Polymeric Nanochannel-Based Electrochemical Biosensor.

The development of simple, cost-effective, rapid, and quantitative diagnostic tools remains critical to monitor infectious COVID-19 disease. Although numerous diagnostic platforms, including rapid antigen tests, are developed and used, they suffer from limited accuracy, especially when tested with asymptomatic patients. Here, a unique approach to fabricate a nanochannel-based electrochemical biosensor that can detect the entire virion instead of virus fragments, is demonstrated. The sensing platform has uniform nanoscale channels created by the convective assembly of polystyrene (PS) beads on gold electrodes. The PS beads are then functionalized with bioreceptors while the gold surface is endowed with anti-fouling properties. When added to the biosensor, SARS-CoV-2 virus particles block the nanochannels by specific binding to the bioreceptors. The nanochannel blockage hinders the diffusion of a redox probe; and thus, allows quantification of the viral load by measuring the changes in the oxidation current before and after virus incubation. The biosensor shows a low limit of detection of ≈1.0 viral particle mL-1 with a wide detection range up to 108 particles mL-1 in cell culture media. Moreover, the biosensor is able to differentiate saliva samples with SARS-CoV-2 from those without, demonstrating the potential of this technology for translation into a point-of-care biosensor product.

Electrochemical biosensing based on graphene for detection of the SARS-Co V-2 Nucleocapsid Protein

Monitoring and controlling infection is required in order to prevent the progression of the coronavirus severe acute respiratory syndrome 2(SARS-Co- V-2). To accomplish this goal, the development and implementation of sensitive, quick and accurate diagnostic methods are essential. Electrochemical sensors have exposed large application possibilities in biological detection due to the advantages of high sensitivity, short time-consuming and specificity. Here, we report the improvement of a sensitive electrochemical sensor capable of detecting the presence of the SARS-CoV-2 virus using graphene-modified interdigitated working electrodes functionalized with antibodies targeting the SARS-CoV-2 nucleocapsid protein (N protein). © 2022 IEEE.

Multiplexed biosensor for point-of-care COVID-19 monitoring: CRISPR-powered unamplified RNA diagnostics and protein-based therapeutic drug management.

In late 2019 SARS-CoV-2 rapidly spread to become a global pandemic, therefore, measures to attenuate chains of infection, such as high-throughput screenings and isolation of carriers were taken. Prerequisite for a reasonable and democratic implementation of such measures, however, is the availability of sufficient testing opportunities (beyond reverse transcription PCR, the current gold standard). We, therefore, propose an electrochemical, microfluidic multiplexed polymer-based biosensor in combination with CRISPR/Cas-powered assays for low-cost and accessible point-of-care nucleic acid testing. In this study, we simultaneously screen for and identify SARS-CoV-2 infections (Omicron-variant) in clinical specimens (Sample-to-result time: ∼30 min), employing LbuCas13a, whilst bypassing reverse transcription as well as target amplification of the viral RNA (LODs of 2,000 and 7,520 copies/µl for the E and RdRP genes, respectively, and 50 copies/ml for combined targets), both of which are necessary for detection via PCR and other isothermal methods. In addition, we demonstrate the feasibility of combining synthetic biology-driven assays based on different classes of biomolecules, in this case protein-based ß-lactam antibiotic detection, on the same device. The programmability of the effector and multiplexing capacity (up to six analytes) of our platform, in combination with a miniaturized measurement setup, including a credit card sized near field communication (NFC) potentiostat and a microperistaltic pump, provide a promising on-site tool for identifying individuals infected with variants of concern and monitoring their disease progression alongside other potential biomarkers or medication clearance.

Conjugated Polymers-Based Biosensors for Virus Detection: Lessons from COVID-19.

Human beings continue to endure the coronavirus disease (COVID-19) pandemic, which has spread throughout the world and significantly affected all countries and territories, causing a socioeconomic crunch. Human pathogenic viruses are considered a global burden for public health, both in the present and the future. Therefore, the early and accurate diagnosis of viruses has been and still is critical and should be accorded a degree of priority that is equivalent to vaccinations and drugs. We have opened a Special Issue titled "Conjugated polymers-based biosensors for virus detection". This editorial seeks to emphasize the importance and potential of conjugated polymers in the design and development of biosensors. Furthermore, we briefly provide an overview, scientific evidence, and opinions on promising strategies for the development of CP-based electrochemical biosensors for virus detection.

ULTRASENSITIVE ELECTROCHEMICAL SENSOR PLATFORM FOR MULTIPLEXED DETECTION OF MULTIPLE ANTI-SARS-CoV-2 IgG

The COVID-19 pandemic has demonstrated the need for better understanding of the kinetics of anti-SARSCoV-2 antibody production and development of serological assays for multiple viral antigens. Electrochemical (EC) sensor platforms offer the potential to develop rapid, sensitive, point-of-care (POC) diagnostics for this type of application. Here, we describe multiplexed EC biosensors with novel antifouling properties that detect anti-SARSCoV-2 immunoglobulin G (IgG) against spike protein (S), spike receptor-binding domain (RBD), and nucleocapsid (NC) antigens. This POC assay was validated using 69 clinical blood samples and obtained 96% sensitivity and 100% specificity with area under the curve (AUC) of 0.98 for multiplexed detection of anti-SARS-CoV-2 IgG. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.

A review of the role of graphene-based nanomaterials in tackling challenges posed by the COVID-19 pandemic

In 2020, the World Health Organization (WHO) declared a pandemic due to the emergence of the coronavirus disease (COVID-19) which was resulted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Significant efforts have been devoted by many countries to develop more advanced medicines and vaccines. However, along with these developments, it is also extremely essential to design effective systems by incorporating smart materials to battle the COVID-19. Therefore, several approaches have been implemented to combat against COVID-19. Recently, due to its superior physicochemical properties along with other fascinating properties, graphene-based materials have been explored for the current COVID-19 and future pandemics. Therefore, in this review article, we discuss the recent progress and the most promising strategies related to graphene and related materials and its applications for detection, decontamination, diagnosis, and protection against COVID-19. In addition, the key challenges and future directives are discussed in detail for fundamental design and development of technologies based on graphene and its related materials and lastly, our personal opinions on the appropriate approaches to improve these technologies respectively.