Figure 7.

The device enables measurement of cytokine levels produced by a single B cell. The ultra-sensitive protein analysis device was developed through a medical-engineering collaboration between the University of Tokyo Graduate School of Engineering and Medicine, which uses a 3 cm × 7 cm glass substrate to create a flow channel for bead enzyme-linked immunosorbent assay to measure cytokine levels with 100 to 1,000 times greater sensitivity than conventional methods. Polystyrene beads attached to primary antibodies are filled into this device and restrained by a dam formed in the flow channel. The analyte in the sample is captured by the primary antibody and subsequently labeled by the second antibody combined with the enzyme. Finally, the enzymatic reaction causes the substrate to emit light, and the signal is detected by thermal lens microscopy.