ABSTRACT
In this work, we report a fast, portable, and economical microfluidic platform for the simultaneous detection of nucleic acid and proteins. Using SARS-CoV-2 as a target, this microfluidic chip enabled to simultaneously detect the SARS-CoV-2 RNA (N gene) antigen (or specific IgG antibody) with respective detection limits of 1 copy/µL for nucleic acid, 0.85 ng/mL for antigen, and 5.80 ng/mL for IgG within 30 min with high stability and anti-interference ability. The capability of this system in clinical applications was further evaluated using clinical samples, displaying 100% sensitivity and 100% specificity for COVID-19 diagnosis. These findings demonstrate the potential of this method to be used for the detection and subsequent control of pathogens.
ABSTRACT
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading worldwide for more than a year and has undergone several mutations and evolutions. Due to the lack of effective therapeutics and long-active vaccines, accurate and large-scale screening and early diagnosis of infected individuals are crucial to control the pandemic. Nevertheless, the current widely used RT-qPCR-based methods suffer from complicated temperature control, long processing time and the risk of false-negative results. Herein, we present a three-way junction induced exponential rolling circle amplification (3WJ-eRCA) combined MALDI-TOF MS assay for SARS-CoV-2 detection. The assay can detect simultaneously the target nucleocapsid (N) and open reading frame 1 ab (orf1ab) genes of SARS-CoV-2 in a single test within 30 min, with an isothermal process (55 °C). High specificity to discriminate SARS-CoV-2 from other coronaviruses, like SARS-CoV, MERS-CoV and bat SARS-like coronavirus (bat-SL-CoVZC45), was observed. We have further used the method to detect pseudovirus of SARS-CoV-2 in various matrices, e.g. water, saliva and urine. The results demonstrated a great potential of the method for large scale screening of COVID-19, which is an important part of the pandemic control.
Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Gene Amplification , Humans , Nucleic Acid Amplification Techniques/methods , RNA, Viral/genetics , SARS-CoV-2/genetics , Sensitivity and Specificity , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
A simple, rapid and robust method to quantify SARS-CoV-2 neutralizing antibodies (nAbs) is urgently needed for determining COVID-19 serodiagnosis, vaccine development and evaluation of vaccine efficacy. In this study, we report sandwich/competitive immuno-sensors based on lateral chromatography micro-interface for accurate quantification of SARS-CoV-2 nAbs. Fluorescent microspheres (FMS) labeled receptor binding domain (RBD) antigen was prepared for detection of nAbs with high sensitivity. Sandwich and competitive immunoassay were conducted on the microfluidic-based sensor within 10 min and the fluorescent signal of immunoassay was analyzed by a portable microfluidic immunoassay instrument. The nAbs detection range of sandwich immuno-sensor and competitive immuno-sensor was 4.0 ng/mL to 400 ng/mL and 2.13 ng/mL to 213 ng/mL, respectively. Furthermore, the sandwich immuno-sensor was demonstrated to be comparable with existing methods and used to detect 182 clinical serum samples from vaccinated individuals. Sandwich immuno-sensor based on lateral chromatography micro-interface allowed reliable, fast, and low-cost detection of nAbs, which holds considerable potential for nAbs testing.
Subject(s)
Antibodies, Neutralizing , COVID-19 , Antibodies, Viral , Humans , Immunoassay , SARS-CoV-2ABSTRACT
An automated Cas12a-microfluidic system was constructed to distinguish the B.1.617.2 (delta) variant of SARS-CoV-2 from the wild-type virus rapidly and was validated using 30 clinical samples, showing 100% consistency with next-generation sequencing. It will be a potential tool for the rapid differential diagnosis of the delta variant of SARS-CoV-2.
Subject(s)
COVID-19/diagnosis , CRISPR-Cas Systems/genetics , Microfluidics/methods , SARS-CoV-2/genetics , Automation , COVID-19/virology , High-Throughput Nucleotide Sequencing , Humans , Mutation , Polymerase Chain Reaction , RNA, Guide, Kinetoplastida/genetics , RNA, Guide, Kinetoplastida/metabolism , RNA, Viral/metabolism , SARS-CoV-2/isolation & purificationABSTRACT
A simple, rapid and robust method to quantify SARS-CoV-2 neutralizing antibodies (nAbs) is urgently needed for determining COVID-19 serodiagnosis, vaccine development and evaluation of vaccine efficacy. In this study, we report sandwich/competitive immuno-sensors based on lateral chromatography micro-interface for accurate quantification of SARS-CoV-2 nAbs. Fluorescent microspheres (FMS) labeled receptor binding domain (RBD) antigen was prepared for detection of nAbs with high sensitivity. Sandwich and competitive immunoassay were conducted on the microfluidic-based sensor within 10 minutes and the fluorescent signal of immunoassay was analyzed by a portable microfluidic immunoassay instrument. The nAbs detection range of sandwich immuno-sensor and competitive immuno-sensor was 4.0 ng/mL to 400 ng/mL and 2.13 ng/mL to 213 ng/mL, respectively. Furthermore, the sandwich immuno-sensor was demonstrated to be comparable with existing methods and used to detect 182 clinical serum samples from vaccinated individuals. Sandwich immuno-sensor based on lateral chromatography micro-interface allowed reliable, fast, and low-cost detection of nAbs, which holds considerable potential for nAbs testing. Graphical abstract Image 1
ABSTRACT
The outbreak of SARS-CoV-2 is posing serious global public health problems. Facing the emergence of this pandemic, we established a portable microfluidic immunoassay system for easy-to-use, sensitive, rapid (<15 min), multiple, and on-site detection of IgG/IgM/Antigen of SARS-CoV-2 simultaneously. This integrated method was successfully applied for detecting SARS-CoV-2 IgM and IgG antibodies in clinical human serum as well as SARS-CoV-2 antigen in pharyngeal swabs from 26 patients with COVID-19 infection and 28 uninfected people. The assay demonstrated high sensitivity and specificity, which is promising for the diagnosis and monitoring as well as control of SARS-CoV-2 worldwide.