Nanomaterials and Biosensing Technology for the SARS-CoV-2 Detection

The outbreak of corona virus disease 2019 (COVID-19) has aroused great attention around the world. SARS-CoV-2 possesses characteristics of faster transmission, immune escape, and occult transmission by many mutation, which caused still grim situation of prevention and control. Early detection and isolation of patients are still the most effective measures at present. So, there is an urgent need for new rapid and highly sensitive testing tools to quickly identify infected patients as soon as possible. This review briefly introduces general characteristics of SARS-CoV-2, and provides recentl overview and analysis based on different detection methods for nucleic acids, antibodies, antigens as detection target. Novel nano-biosensors for SARS-CoV-2 detection are analyzed based on optics, electricity, magnetism, and visualization. In view of the advantages of nanotechnology in improving detection sensitivity, specificity and accuracy, the research progress of new nano-biosensors is introduced in detail, including SERS-based biosensors, electrochemical biosensors, magnetic nano-biosensors and colorimetric biosensors. Functions and challenges of nano-materials in construction of new nano-biosensors are discussed, which provides ideas for the development of various coronavirus biosensing technologies for nanomaterial researchers.

Multipurpose advanced split T7 promoter-based transcription amplification for ultrasensitive molecular diagnostics

An accurate, convenient, and rapid diagnostic platform, which can be applied in facility-limited or point-of-care (POC) settings, is essential to help prevent the spread of infectious diseases and enable the most effective treatment to be selected. In this study, we describe the development of a new isothermal molecular diagnostic system named multipurpose advanced split T7 promoter-based transcription amplification (MASTER) for the rapid and ultrasensitive detection of various pathogens containing single-stranded RNA and double-stranded DNA. MASTER produces a large number of RNA amplicons in the presence of target pathogens, which generate fluorescence or colorimetric signals based on light-up RNA aptamers or lateral flow assays. Implementing MASTER at 37 °C for<1 h achieved the detection of a single copy per reaction without cross-reactivity. Moreover, the testing of 40 clinical samples revealed that MASTER exhibited excellent accuracy with 100% sensitivity and specificity for SARS-CoV-2 diagnosis. Furthermore, a one-pot MASTER system capable of accelerating practical applications was demonstrated, indicating that the MASTER system is a promising platform for the effective surveillance of various pathogens. © 2023 Elsevier B.V.

Magneto-Nanomechanical Array Biosensor for Ultrasensitive Detection of Oncogenic Exosomes for Early Diagnosis of Cancers.

Exosomes are a class of nanoscale vesicles secreted by cells, which contain abundant information closely related to parental cells. The ultrasensitive detection of cancer-derived exosomes is highly significant for early non-invasive diagnosis of cancer. Here, an ultrasensitive nanomechanical sensor is reported, which uses a magnetic-driven microcantilever array to selectively detect oncogenic exosomes. A magnetic force, which can produce a far greater deflection of microcantilever than that produced by the intermolecular interaction force even with very low concentrations of target substances, is introduced. This method reduced the detection limit to less than 10 exosomes mL-1 . Direct detection of exosomes in the serum of patients with breast cancer and in healthy people showed a significant difference. This work improved the sensitivity by five orders of magnitude as compared to that of traditional nanomechanical sensing based on surface stress mode. This method can be applied parallelly for highly sensitive detection of other microorganisms (such as bacteria and viruses) by using different probe molecules, which can provide a supersensitive detection approach for cancer diagnosis, food safety, and SARS-CoV-2 infection.

Nanomaterials and Biosensing Technology for the SARS-CoV-2 Detection

The outbreak of corona virus disease 2019 (COVID-19) has aroused great attention around the world. SARS-CoV-2 possesses characteristics of faster transmission, immune escape, and occult transmission by many mutation, which caused still grim situation of prevention and control. Early detection and isolation of patients are still the most effective measures at present. So, there is an urgent need for new rapid and highly sensitive testing tools to quickly identify infected patients as soon as possible. This review briefly introduces general characteristics of SARS-CoV-2, and provides recentl overview and analysis based on different detection methods for nucleic acids, antibodies, antigens as detection target. Novel nano-biosensors for SARS-CoV-2 detection are analyzed based on optics, electricity, magnetism, and visualization. In view of the advantages of nanotechnology in improving detection sensitivity, specificity and accuracy, the research progress of new nano-biosensors is introduced in detail, including SERS-based biosensors, electrochemical biosensors, magnetic nano-biosensors and colorimetric biosensors. Functions and challenges of nano-materials in construction of new nano-biosensors are discussed, which provides ideas for the development of various coronavirus biosensing technologies for nanomaterial researchers.

MXene-Based Nanomaterials for Biomedical Applications: Healthier Substitute Materials for the Future

MXene-based nanomaterial is a revolution 2D material achieving outstanding scientific attention owing to its universal characteristics for different applications (such as electronic appliances, power production, sensors, drug transfer, and biomedical). Although, the cytotoxic consequences of MXene have a considerable circumstance. Thus, rigorous investigation of the biocompatibility of MXene is a crucial prerequisite, formerly the preface to the human biological approach. Literature reveals functional outcomes wherever MXenes are used in vitro and in vivo cancer representatives. It affects drug transfer methods, sensoring electrodes, and assisting mechanisms for photothermal treatment and hyperthermy techniques. In this review, the synthesis process (such as top-down and bottom-up approaches) and properties (such as mechanical, electrical, optical, oxidative/thermal stability, and magnetic) of MXene-based nanomaterials (NMs) are discussed. In addition, the different applications (such as tissue engineering, cancer theranostic, and other biomedical [such as drug delivery biosensors and surface-enhanced Raman spectroscopy substrates for biomedical applications], antiviral, and immunomodulatory properties against SARS-CoV-2) of MXene-based NMs are discussed in detail. Finally, the conclusion, existing challenges, and future outlooks are highlighted for more scope in this field.

CRISPR-based electrochemical sensor for COVID-19 diagnostics

We report the development of an electrochemical sensor platform for ultrasensitive and rapid detection of SARS-CoV-2 viral RNA that integrates loop-mediated isothermal amplification (LAMP), CRISPR-based detection, and anti-fouling nanocomposite coating. By integrating LAMP amplification with CRISPR, we achieved ultrasensitive detection of SARS-CoV-2 RNA at levels as low as 5 copies µL-1. Data from this electrochemical diagnostic platform was comparable to traditional RT-PCR methodology in a fraction of the time, at low cost, and without requiring laboratory space. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.

ULTRASENSITIVE AND RAPID DETECTION OF COVID-19 VIRUS USING DUAL-CLAMPED SURFACE-ENHANCED-RAMAN-SCATTERING NANOSENSORS

The COVID-19 outbreak spreads around world, accumulated to more than 27 million confirmed cases and 800k deaths. Polymerase Chain Reaction (PCR), a gold-standard diagnostic method, were labor intensive, time-consuming and costly, which restricted its application to widespread screening. Herein, this study purposes a one-pot and non-washing method to rapidly detect virus by dual-clamped surface-enhanced Raman scattering (SERS) mechanism. COVID Antigens were captured by SERS nanoparticles and novel SERS substrate simultaneously to achieve 6 order enhancements within 20 minutes. The dual-SERS sensors have reached a detection limit of 1 ng/ml in clinical samples for recognizing nucleocapsid & Spike proteins of COVID-19, which is comparable with PCR results. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.

A Rebuilding-Free Nucleic Acid Detection Strategy Enables Ultrasensitive Genotyping, N-in-1 Logic Screening and Accurate Multiplex Assay of Dangerous Pathogens.

Sensitive, rapid and low-cost nucleic acid detection is critical for controlling infectious pathogens. Here, we develop a ready-to-use and multimodal detection based on a rebuilding-free, ultrasensitive and selective strategy named dual hairpin ligation-induced isothermal amplification pro (DHLApro). Taking influenza A, influenza B, MERS-CoV, SARS-CoV-2 as model targets, we demonstrate DHLApro provides ≈zM level ultra-sensitivity, being equaling to 0.45 copy/µL in original sample. By simply changing the recognition module, a set of DHLApro components can be applied to a new target without performance loss. Moreover, DHLApro innovatively allows flexible logic/multiplex assay using one set of primer, for example, the "N pathogens-in-1" OR gate screening and accurate multi-channel multiplex assay. Compared with traditional methods, the cost of this logic/multiplex assay has been largely reduced and the cross-interference between the multiple primer sets is also avoided.

Highly Sensitive Flexible SERS-Based Sensing Platform for Detection of COVID-19.

COVID-19 continues to spread and has been declared a global emergency. Individuals with current or past infection should be identified as soon as possible to prevent the spread of disease. Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that has the potential to be used to detect viruses at the site of therapy. In this context, SERS is an exciting technique because it provides a fingerprint for any material. It has been used with many COVID-19 virus subtypes, including Deltacron and Omicron, a novel coronavirus. Moreover, flexible SERS substrates, due to their unique advantages of sensitivity and flexibility, have recently attracted growing research interest in real-world applications such as medicine. Reviewing the latest flexible SERS-substrate developments is crucial for the further development of quality detection platforms. This article discusses the ultra-responsive detection methods used by flexible SERS substrate. Multiplex assays that combine ultra-responsive detection methods with their unique biomarkers and/or biomarkers for secondary diseases triggered by the development of infection are critical, according to this study. In addition, we discuss how flexible SERS-substrate-based ultrasensitive detection methods could transform disease diagnosis, control, and surveillance in the future. This study is believed to help researchers design and manufacture flexible SERS substrates with higher performance and lower cost, and ultimately better understand practical applications.

Exploring the entropy-driven amplification reaction and trans-cleavage activity of CRISPR-Cas12a for the development of an electrochemiluminescence biosensor for the detection of the SARS-CoV-2 RdRp gene in real samples and environmental surveillance

In this paper, we present the first idea of using a DNA triple helix structure to inhibit CRISPR-Cas12a activity and apply it to the design of an electrochemiluminescent biosensor for the detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) gene in real samples and environmental surveillance. We employed a segment from the RdRp gene of SARS-CoV-2 by an entropy-driven reaction, which was paired with double-stranded DNA that can activate CRISPR-Cas12a activity by Hoogsteen pairing to form triple-stranded DNA, thereby inhibiting the binding interaction of the double-stranded DNA with CRISPR-Cas12a, which in turn inhibits the trans cleavage activity of CRISPR-Cas12a. The inhibited CRISPR-Cas12a is unable to cut the nucleic acid modified on the electrode surface, resulting in the inability of the ferrocene (Fc) modified on the other end of the nucleic acid to move away from the electrode surface, and thus failing to cause electrochemiluminescence changes in GOAu-Ru modified on the electrode surface. The extent of the electrogenic chemiluminescence change can reflect the concentration of the gene to be tested. Using this system, we achieved the detection of the SARS-CoV-2 RdRp gene with a detection limit of 32.80 aM.

Establishment of method for dual simultaneous detection of PEDV and TGEV by combination of magnetic micro-particles and nanoparticles.

Transmissible gastroenteritis virus (TGEV) and porcine epidemic diarrhea virus (PEDV) are the main pathogens causing viral diarrhea in pig, mixed infections of these two viruses are very common in intensive pig rearing. However, there is a lack of a method to simultaneously detect and distinguish PEDV and TGEV in preclinical levels. In this study, we aimed to establish a dual ultrasensitive nanoparticle DNA probe-based PCR assay (dual UNDP-PCR) based on functionalized magnetic bead enrichment and specific nano-technology amplification for simultaneous detection and distinguish diagnosis of PEDV and TGEV. The detection limit of dual UNDP-PCR for single or multiple infections of PEDV and TGEV is 25 copies/g, which is 400 times more sensitive than the currently known duplex RT-PCR, showing better specificity and sensitivity without cross-reaction with other viruses. For pre-clinical fecal samples, the dual UNDP-PCR showed a markedly higher positive detection rate (52.08%) than conventional duplex RT-PCR (13.21%), can rapidly and accurately identify targeted pathogens whenever simple virus infection or co-infection. In summary, this study provides a technique for detecting and distinguishing PEDV and TGEV in preclinical levels, which is high sensitivity, specificity, repeatability, low cost and broad application prospect.