Quartz Crystal Microbalance Platform for SARS-CoV-2 Immuno-Diagnostics

Area of Science:

• Biomedical Engineering
• Immunology
• Analytical Chemistry

Background:

• Accurate serological analysis of SARS-CoV-2 antibodies is crucial for assessing immunity and tracking viral spread.
• Quartz crystal microbalance (QCM) is a label-free sensor technology enabling real-time detection of molecular binding events.
• Existing serological assays, such as ECLIA and CLIA, provide valuable but distinct detection methods for SARS-CoV-2 antibodies.

Purpose of the Study:

• To develop and evaluate a QCM-based immunoassay for the detection of SARS-CoV-2 specific IgG antibodies.
• To assess the reproducibility and linearity of the developed QCM immunoassay.
• To compare the performance of the QCM immunoassay against established commercial serological tests.

Main Methods:

• Development of a QCM sensor platform for real-time detection of SARS-CoV-2 antibody binding.
• Evaluation of assay reproducibility using day-to-day correlation analysis (r² = 0.99).
• Assessment of assay linearity through serial dilutions in serum and buffer (r² = 0.96).
• Cross-comparison of the QCM assay with Roche ECLIA and YHLO CLIA using 119 human serum samples.

Main Results:

• The QCM immunoassay exhibited excellent day-to-day reproducibility (r² = 0.99) and linearity (r² = 0.96).
• Cross-comparison with commercial assays showed good coherence, with positive agreement ranging from 80-100% and negative agreement from 96-100%.
• The QCM assay identified 48 positive samples out of 119, compared to 59 for Roche and 52 for YHLO.

Conclusions:

• The developed QCM-based SARS-CoV-2 IgG immunoassay is highly reproducible and linear.
• The QCM assay demonstrates good agreement with established ELISA-based serological methods.
• Factors like antibody titer and binding affinity may influence results across different assay platforms.