Anti-SARS-CoV-2 IgG and IgM detection with a GMR based LFIA system

Abstract

Since December 2019, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused millions of deaths and seriously threatened the safety of human life; indeed, this situation is worsening and many people are infected with the new coronavirus every day. Therefore, it is very important to understand patients’ degree of infection and infection history through antibody testing. Such information is useful also for the government and hospitals to formulate reasonable prevention policies and treatment plans. In this paper, we develop a lateral flow immunoassay (LFIA) method based on superparamagnetic nanoparticles (SMNPs) and a giant magnetoresistance (GMR) sensing system for the simultaneously quantitative detection of anti-SARS-CoV-2 immunoglobulin M (IgM) and G (IgG). A simple and time-effective co-precipitation method was utilized to prepare the SMNPs, which have good dispersibility and magnetic property, with an average diameter of 68 nm. The Internet of Medical Things-supported GMR could transmit medical data to a smartphone through the Bluetooth protocol, making patient information available for medical staff. The proposed GMR system, based on SMNP-supported LFIA, has an outstanding advantage in cost-effectiveness and time-efficiency, and is easy to operate. We believe that the suggested GMR based LFIA system will be very useful for medical staff to analyze and to preserve as a record of infection in COVID-19 patients.

Rapid Detection of Anti-SARS-CoV-2 Antibody Using a Selenium Nanoparticle-Based Lateral Flow Immunoassay

“…The sensitivity, specificity, positive predictive value, and negative predictive value of the kit were calculated according to the following formulas [21] : \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}\begin{align*} \text {Sensitivity}=&\Biggl[\text {True Positive}/\Biggl(\text{True Positive} \\&+\, \text {False Negative}\Biggr)\Biggr] \times 100{\%}\\ \text {Specificity}=&\Biggl[\text {True negative} / \Biggl(\text {True Negative} \\&+\, \text {False Positive}\Biggr)\Biggr] \times 100{\%}\\ \text {Positive predictive value}=&\Biggl[\text {True Positive} / \Biggl(\text {True Positive} \\&+\, \text {False Positive}\Biggr)\Biggr] \times 100{\%}\\ \text {Negative predictive value}=&\Biggl[\text {True Negative} / \Biggl(\text {False Negative} \\&+\, \text {True Negative}\Biggr)] \times 100{\%}\end{align*} \end{document} …”

“…We confirm that the detection results of COVID-19 patients in this study have not been reported in any other submission by us or anyone else. The sensitivity, specificity, positive predictive value, and negative predictive value of the kit were calculated according to the following formulas [21]…”

Point-of-care COVID-19 diagnostics powered by lateral flow assay

“…Inspired by this pioneering work, increasing efforts have been devoted to improve the multiple sensing capability of LFIA for the sensitive and simultaneous detection of SARS-CoV-2-specific IgM and IgG [ 112 , 113 ]. Among these studies, except for the common AuNPs [ 114 , 115 ], other nanomaterials including selenium nanoparticle, quantum dots (QDs) [ 116 ] or QD nanobeads [ 117 ], lanthanide fluorescent microsphere [ 118 ], aggregation-induced emission based polymeric nanoparticles [ 119 ], core–shell SiO 2 @AgNPs [ 120 ], and magnetic nanoparticles [ 121 ], have also been used in LFIA for enhancing the detection of SARS-CoV-2 antibodies with the help of sensitive signal outputs of colorimetry, fluorescence, surface enhanced Raman scattering, and giant magnetoresistance. In addition, the serologic test performance of these reported multiple LFIA for COVID-19 can be further improved by integrating with a machine-learning classifier to control the false positive rate at a targeted level [ 122 ].…”

High Sensitivity and Label-Free Detection of the SARS-CoV-2 S1 Protein Using a Terahertz Meta-Biosensor

“…At present, great advancements have been made to achieve the diagnosis of SARS-CoV-2, including reverse transcription-polymerase chain reaction (RT-PCR) and the antibody detection method [6][7][8][9][10][11]. Based on the known RNA sequence of the virus, the RT-PCR technique can be used to convert the viral RNA in the nasal or the throat into DNA, and the DNA concentration will be subsequently amplified and detectable.…”