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
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
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.