title: Synthesis and Characterization of Anti-HER2 Antibody Conjugated CdSe/CdZnS Quantum Dots for Fluorescence Imaging of Breast Cancer Cells.
abstract: The early detection of HER2 (human epidermal growth factor receptor 2) status in breast cancer patients is very important for the effective implementation of anti-HER2 antibody therapy. Recently, HER2 detections using antibody conjugated quantum dots (QDs) have attracted much attention. QDs are a new class of fluorescent materials that have superior properties such as high brightness, high resistance to photo-bleaching, and multi-colored emission by a single-light source excitation. In this study, we synthesized three types of anti-HER2 antibody conjugated QDs (HER2Ab-QDs) using different coupling agents (EDC/sulfo-NHS, iminothiolane/sulfo-SMCC, and sulfo-SMCC). As water-soluble QDs for the conjugation of antibody, we used glutathione coated CdSe/CdZnS QDs (GSH-QDs) with fluorescence quantum yields of 0.23∼0.39 in aqueous solution. Dispersibility, hydrodynamic size, and apparent molecular weights of the GSH-QDs and HER2Ab-QDs were characterized by using dynamic light scattering, fluorescence correlation spectroscopy, atomic force microscope, and size-exclusion HPLC. Fluorescence imaging of HER2 overexpressing cells (KPL-4 human breast cancer cell line) was performed by using HER2Ab-QDs as fluorescent probes. We found that the HER2Ab-QD prepared by using SMCC coupling with partially reduced antibody is a most effective probe for the detection of HER2 expression in KPL-4 cells. We have also studied the size dependency of HER2Ab-QDs (with green, orange, and red emission) on the fluorescence image of KPL-4 cells.
authors.affiliation: WPI Immunology Frontier Research Center, Osaka University, Yamada-oka 1-3, Suita, Osaka 565-0871, Japan; E-Mails:  mdkdragon@gmail.com  (D.T.);  kyoshizawa@fbs.osaka-u.ac.jp  (K.Y.);  twatanabemeister@gmail.com  (T.W.).
authors.forename: Dhermendra K
authors.initials: DK
authors.lastname: Tiwari
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Inouye
authors.forename: Keiko
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Tomonobu M
authors.initials: TM
authors.lastname: Watanabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Jin