Comparative performance of three optical biosensing platforms for SARS-CoV-2 antibodies detection in human serum

TL;DR

This paper compares two optical biosensing platforms, BSW and MRR, for detecting SARS-CoV-2 antibodies in human serum, demonstrating their rapid, sensitive, and reproducible performance for clinical diagnostics.

Contribution

It provides a direct comparative analysis of BSW and MRR biosensors under identical conditions, establishing their suitability for COVID-19 serology testing.

Findings

Both platforms detect SARS-CoV-2 antibodies rapidly and quantitatively.

They show high sensitivity and agreement with serology benchmarks.

The platforms are reproducible across different biochip batches.

Abstract

This study presents a rigorous comparative analysis of two label-free optical biosensing platforms, Bloch surface wave (BSW) and microring resonator (MRR), for the detection of SARS-CoV-2 antibodies in human serum. To ensure direct comparability, a new BSW readout system was established alongside an existing MRR platform, allowing assays to be conducted under nearly identical experimental conditions. Both sensors were functionalized with various SARS-CoV-2 Spike and Nucleocapsid protein variants to capture specific host antibodies. The results demonstrate that both platforms provide rapid, quantitative, and sensitive detection of anti-Spike and anti-Nucleocapsid antibodies without the need for secondary labels. Furthermore, the platforms show excellent agreement with longitudinal serology benchmarks and high repeatability across different biochip batches. This work establishes both BSW and MRR technologies as powerful, low-cost candidates for next-generation clinical diagnostics and serological surveillance.