Development of a quantitative diagnostic method of estrogen receptor expression levels by immunohistochemistry using organic fluorescent material-assembled nanoparticles

► Organic fluorescent material-assembled nanoparticles for IHC were prepared. ► New nanoparticle fluorescent intensity was 10.2-fold greater than Qdot655. ► Nanoparticle staining analyzed a wide range of ER expression levels in tissue. ► Nanoparticle staining enhanced the quantitative sensitivity for ER diagnosis.