Brief Communication: Magnetic Immuno-Detection of SARS-CoV-2 specific Antibodies

Abstract

10SARS-CoV-2 causes ongoing infections worldwide, and identifying people with immunity is 11 becoming increasingly important. Available point-of-care diagnostic systems as lateral flow assays 12 have high potential for fast and easy on-site antibody testing but are lacking specificity, sensitivity 13 or possibility for quantitative measurements. Here, a new point-of-care approach for SARS-CoV-2 14 specific antibody detection in human serum based on magnetic immuno-detection is described and 15 compared to standard ELISA. For magnetic immuno-detection, immunofiltration columns were 16 coated with a SARS-CoV-2 spike protein peptide. SARS-CoV-2 peptide reactive antibodies, spiked 17 at different concentrations into PBS and human serum, were rinsed through immunofiltration 18 columns. Specific antibodies were retained within the IFC and labelled with an isotype specific 19 biotinylated antibody. Streptavidin-functionalized magnetic nanoparticles were applied to label the 20 secondary antibodies. Enriched magnetic nanoparticles were then detected by means of frequency 21 magnetic mixing detection technology, using a portable magnetic read-out device. Measuring 22 signals corresponded to the amount of SARS-CoV-2 specific antibodies in the sample. Our 23 preliminary magnetic immuno-detection setup resulted in a higher sensitivity and broader 24 2 detection range and was four times faster than ELISA. Further optimizations could reduce assay 25 times to that of a typical lateral flow assay, enabling a fast and easy approach, well suited for point-26 of-care measurements without expensive lab equipment.

Development of Fast and Portable Frequency Magnetic Mixing-Based Serological SARS-CoV-2-Specific Antibody Detection Assay

“…A major advantage of the developed serological magnetic immunodetection compared to the current FDA-approved LFD-based assays is that a SARS-CoV-2-specific antibody titer evaluation can be performed rapidly, and an estimation of the amount of antibody in serum can be achieved solely by the resulting measurement signal at 40-fold assay dilution. For an absolute quantitative determination of the antibody amount, a calibration measurement similar to Pietschmann et al (2020c) or, alternatively, an antibody titer determination needs to be performed. However, the data reflect the SARS-CoV-2-specific immune status of the tested individual and can be used for the identification of previously infected persons as well as for monitoring of vaccine efficiency over time, to develop adaptive prime-boost regimens, especially in cases when there is a scarcity of vaccination doses.…”

“…Here, magnetic immunodetection (MID) based on sensing superparamagnetic particles by frequency magnetic mixing detection (FMMD) technology might be a powerful tool. The implementation of MID-based assays for the detection of various antigens like bacterial and fungal toxins, plant and human pathogens, as well as peptide-specific antibodies was previously demonstrated ( Meyer et al, 2007a , b , c ; Rettcher et al, 2015 ; Achtsnicht et al, 2019a ; Pietschmann et al, 2020a , b , c . The basic principle of magnetic immunodetection is the specific enrichment of an analyte within an immunofiltration column (IFC) and its subsequent labeling with functionalized magnetic nanoparticles, resulting in an analyte dose-dependent retention of particles.…”

“…The basic principle of magnetic immunodetection is the specific enrichment of an analyte within an immunofiltration column (IFC) and its subsequent labeling with functionalized magnetic nanoparticles, resulting in an analyte dose-dependent retention of particles. Subsequently a particle-dose-depending measuring signal in millivolt (mV) is obtained, using a portable measuring FMMD device ( Krause et al, 2007 ; Achtsnicht et al, 2019a , c ; Pietschmann et al, 2020a , b , c . With this, a correlation between antigen and measuring signal can be seen, resulting not only in a qualitative but also quantitative data.…”

An overview of technologies and devices against COVID-19 pandemic diffusion: virus detection and monitoring solutions

“…For example, the platform, in ref. Pietschmann et al (2020), is a surface-based immunoassay platform MInD (magnetic immunodetection) for the detection of SARS-CoV-2-specific antibodies. In their work, a porous polyethylene filter matrix coated with a SARS-CoV-2 spike-protein peptide acts as the reaction surface.…”

An Analysis Review, Detection Coronavirus Disease 2019 (COVID-19) based on Biosensor Application

“…A new method is proposed and compared with standard ELISA for SARS-CoV-2 detection in specific antibody serum based on magnetic immuno-detection. was time duration 42 min after The isolation and purification of the sample taken [115]. precedent study Popular biosensors systems based on magnetic such as magnetoresistance, magnetic particle spectroscopy sensors, and nuclear magnetic resonance have been reviewed.…”