Chemiluminescence (CL) Assay.

Procedures were the same as for colorimetry except for the CL development and detection. Supersignal West Femto reagent was used to develop CL that was recorded with a CCD camera in a dark box. Tips with sandwich immunocomplex decorated with HRP were filled with luminol reagent prepared by mixing equal volumes of luminol/enhancer substrate and hydrogen peroxide solution according to vendor specifications. Tips with CL reagent were then immediately placed into the dark box, and images were captured over 120 s (Figure 1C). Images were analyzed using GeneTools software (Syngene) to convert to relative CL intensity.