Theranostics 2017; 7(4):952-961. doi:10.7150/thno.16647

Research Paper

Antigen-responsive molecular sensor enables real-time tumor-specific imaging

Hyunjin Kim1, Hak Soo Choi2, Seok-Ki Kim1, Byung Il Lee3, Yongdoo Choi1✉

1. Molecular Imaging and Therapy Branch, National Cancer Center, 323 Ilsan-ro, Goyang, Gyeonggi 10408, Republic of Korea.
2. Gordon Center for Medical Imaging, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
3. Biomolecular Function Research Branch, National Cancer Center, 323 Ilsan-ro, Goyang, Gyeonggi 10408, Republic of Korea.

Abstract

Antibody-fluorophore conjugates have high potential for the specific fluorescence detection of target cancer cells in vitro and in vivo. However, the antibody-fluorophore conjugates described to date are inappropriate for real-time imaging of target cells because removal of unbound antibody is required to reduce background fluorescence before quantifiable analysis by microscopy. In addition, clinical applications of the conjugates have been limited by persistent background retention due to their long systemic circulation and nonspecific uptake. Here we report fast and real-time near-infrared fluorescence imaging of target cancer cells using an antigen-responsive molecular “on-off” sensor: the fluorescence of trastuzumab-ATTO680 conjugate is dark (i.e., turned off) in the extracellular region, while it becomes highly fluorescent (i.e., turned on) upon binding to the target antigen HER2 on cancer cell surface. This molecular switch enables fast and real-time imaging of target cancer cells in vitro and in vivo.

Keywords: Antigen-responsive, near-infrared fluorescence imaging, real-time imaging.

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How to cite this article:
Kim H, Choi HS, Kim SK, Lee BI, Choi Y. Antigen-responsive molecular sensor enables real-time tumor-specific imaging. Theranostics 2017; 7(4):952-961. doi:10.7150/thno.16647. Available from http://www.thno.org/v07p0952.htm