For comparison, CA125 antigen at various concentrations was immobilized with on a 24-well cell culture plate. After drying at RT for 3 h, BSA was reacted with CA125 antigen for 1.5 h to block nonspeciﬁc immobilization of undesired biomolecules. Each well was rinsed once with the phosphate-buffered saline with Tween 20 (PBST) buffer, which contains 3.2 mM , 0.5 mM , 1.3 mM KCl, 135 mM NaCl, and 0.05% (v/v) Tween 20, pH 7.4. After another 1.5 h, IRDye-labeled secondary antibody (LI-COR, Inc., Lincoln, Nebraska) with a dilution ratio of was added to each well to react with the CA125 antigen–antibody complex at RT for 0.5 h. Each well was rinsed once with PBST buffer and twice with PBS prior to fluorescence detection. The fluorescence signal and image were acquired with an Odyssey® Infrared Imaging System (LI-COR, Inc., Lincoln, Nebraska) equipped with a solid-state diode laser at 785 nm.