Open AccessNew generation ICG-based contrast agents for ultrasound-switchable fluorescence imaging
Author(s) -
Shuai Yu,
Bingbing Cheng,
Tingfeng Yao,
Chunli Xu,
Kytai T. Nguyen,
Yi Hong,
Baohong Yuan
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep35942
Subject(s) - indocyanine green , fluorescence , fluorescence lifetime imaging microscopy , contrast (vision) , conjugated system , nanoparticle , near infrared spectroscopy , in vivo , ultrasound , biomedical engineering , materials science , nanotechnology , computer science , medicine , radiology , optics , surgery , artificial intelligence , polymer , biology , physics , microbiology and biotechnology , composite material
Recently, we developed a new technology, ultrasound-switchable fluorescence (USF), for high-resolution imaging in centimeter-deep tissues via fluorescence contrast. The success of USF imaging highly relies on excellent contrast agents. ICG-encapsulated poly(N-isopropylacrylamide) nanoparticles (ICG-NPs) are one of the families of the most successful near-infrared (NIR) USF contrast agents. However, the first-generation ICG-NPs have a short shelf life (<1 month). This work significantly increases the shelf life of the new-generation ICG-NPs (>6 months). In addition, we have conjugated hydroxyl or carboxyl function groups on the ICG-NPs for future molecular targeting. Finally, we have demonstrated the effect of temperature-switching threshold (T th ) and the background temperature (T BG ) on the quality of USF images. We estimated that the T th of the ICG-NPs should be controlled at ~38–40 °C (slightly above the body temperature of 37 °C) for future in vivo USF imaging. Addressing these challenges further reduces the application barriers of USF imaging.