A nanofluidic device for rapid and multiplexed SARS-CoV-2 serological antibody detection

The outbreak of COVID-19 has led to a substantial death toll and has hindered the functioning of modern society, sending the world into a medical and economic crisis1,2. This underlined the importance of point-of-care diagnostics, as well as accurate, cost-effective serological antibody tests as well as point-of-care diagnostics to monitor the viral spread and contain pandemics and endemics. Here, we present a three-dimensional (3D) nanofluidic device for rapid and multiplexed detection of viral antibodies. The device is designed to size-dependently immobilize particles from a multi-particle mixture at predefined positions in nanochannels through capillary forces only, resulting in distinct trapping lines. We show that individual lines can be used as an on-chip fluorescence-linked immunosorbent assay for multiplexed detection of serological immunoglobulin antibodies against viral proteins with high sensitivity. Further device versatility is exhibited by on-bead color multiplexing for simultaneous detection of IgG and IgM antibodies in convalescent human serum and by concurrent detection of anti-spike (SARS-CoV-2) and anti-hemagglutinin (Influenza A) antibodies. The device’s applications can be further extended to detect a plethora of diseases simultaneously in a reliable and straightforward manner.