Microfluidic immunocytochemical staining system for efficient immunoreaction

Immunocytochemistry (ICC) has been used for assessing antibodies that target specific antigens in a cell via specific epitopes. Although ICC has been regarded as a well established method, it requires many steps for immunoreactions and long time over 4 h. It means that more efficient immunocytochemical staining method should be developed. Moreover, many biological studies demand quantitative comparison for expression of various antibodies. Here, we have developed a novel microfluidic immunocytochemical staining method to improve the efficiency of color reaction and to enable quantitative comparison for various antibodies on a cell specimen. To realize fluid control with microvalves and uniform fluid velocity across the reaction channels of the device, two-step multilayer soft lithography technique was introduced. The system was automatically controlled for reagents and flow rate, solving the variability of ICC staining and the labor intensiveness of ICC. The microfluidic system made efficient mass transport for reagents and antibodies at near the sample and the phenomenon was proved by computational fluid dynamics (CFD) study. Results showed that reaction time was more significantly affected in immunoreaction than flow rate.