Holographic Immunoassays: Battling COVID-19 with Soft Matter Physics*

Holographic immunoassays use holographic particle characterization to measure growth in the mean diameter of thousands of colloidal beads due to the binding of antibodies to the probe bead surface. This measurement has the advantage of being label-free; binding can be detected without fluorescent labeling of the biomolecules. This reduces the cost and complexity of the technique compared with traditional assays like ELISA. Additionally, the probe beads can be batch synthesized and functionalized without the need for microfabrication. Our work on this topic measured the kinetics of irreversible binding of immunoglobulin G (IgG) and immunoglobulin M (IgM) to protein A coated probe beads. These measurements were used to determine the antibody binding rates and can be inverted to determine the concentration of antibodies in solution. This technique shows promise for detecting Antibody Deficiency Disorders and for the detection of antibodies for SARS COV-2 and other infections.

"The first two authors contributed equally to this work."