Patent ID: 8512950

Claim:
A method of determining the amount of a target molecule based on the amount of peroxidase reaction product deposited on a biosensor, the method comprising: a) exposing the biosensor to a sample containing the target molecule, the surface of the biosensor comprising a capture probe with specific affinity for the target molecule, b) allowing the target molecule to bind to the capture probe, c) allowing a target detection molecule to bind to the target molecule, d) allowing a peroxidase enzyme to bind to the target detection molecule, e) allowing the peroxidase enzyme to react with colloidal casein in the presence of dithiothreitol and in the absence of H 2 O 2 wherein a peroxidase reaction product is deposited on the biosensor, f) determining the amount of the peroxidase reaction product deposited on the biosensor using biolayer interferometry, and g) determining the amount of the target molecule based on the amount of the peroxidase reaction product deposited on the biosensor.