Development of a microfluidic device operated by manual pipetting for immunohistochemistry

Abstract

Immunohistochemistry (IHC), which has been used to detect antigens in cells of a tissue section using an immunoreaction between antibody and antigen, is a practical tool for identifying the type and stage of disease in cancer diagnosis and scientific research. However, conventional IHC requires long, laborious process times and high costs. Although microfluidic based IHC platforms have been developed to overcome these limitations, the distribution of microfluidic IHC in the real field is still limited by the additional equipment needed to operate the microfluidic systems. In addition, continuous flow in a microfluidic channel leads to a waste of unbounded antibodies. In this thesis, a novel and easy-to-use microfluidic IHC platform is demonstrated. The microfluidic system is operated only by a manual pipette that is commonly available in research laboratories or hospitals. Bidirectional circulation flows of antibody solution in a microchannel are induced by repetitive manual pipetting which facilitates the antigen-antibody reaction and enables the effective use of a limited amount of antibody. When breast cancer cell and tissue sections are reacted with antibody using this platform, pipetting less than 2 min is sufficient to obtain immunostaining results without damaging the sample. The staining intensity by this method is similar to that of the sample stained for 1 h by a conventional batch process. It is expected that this pipetting-based approach for operating microfluidic system allows end-users to use microfluidic-based IHC more conveniently and easily in real world environments.