Generation of an scFv-type Quenchbody Against HER2 for Sensitive Detection of Human Breast Cancer

Abstract

The advanced clinical stage of breast cancer causes a lower survival rate even though the survival rate in the early stages is relatively high. Thus, the development of a rapid and easy-to-access diagnostic method is needed. In this study, a single chain Fv (scFv)-type antibody fragment that binds to HER2, a transmembrane protein overexpressed on breast cancer cells, was generated. The scFv was converted to a Quenchbody by site-specifically labeling the scFv using fluorescent dye through a maleimide-thiol reaction. The Quenchbody could detect a picomolar order of HER2 in a few minutes, and its signal-to-background ratio of fluorescence intensity was higher than a fluorescence scFv generated through a conventional fluorescent dye-conjugating method. The Quenchbody can be used as a probe for detecting and imaging of breast cancer cells for point-of-care diagnosis of breast cancer.