title: Cancer-Microenvironment-Sensitive Activatable Quantum Dot Probe in the Second Near-Infrared Window.
abstract: Recent technological advances have expanded fluorescence (FL) imaging into the second near-infrared region (NIR-II; wavelength = 1000-1700 nm), providing high spatial resolution through deep tissues. However, bright and compact fluorophores are rare in this region, and sophisticated control over NIR-II probes has not been fully achieved yet. Herein, we report an enzyme-activatable NIR-II probe that exhibits FL upon matrix metalloprotease activity in tumor microenvironment. Bright and stable PbS/CdS/ZnS core/shell/shell quantum dots (QDs) were synthesized as a model NIR-II fluorophore, and activatable modulators were attached to exploit photoexcited electron transfer (PET) quenching. The quasi type-II QD band alignment allowed rapid and effective FL modulations with the compact surface ligand modulator that contains methylene blue PET quencher. The modulator was optimized to afford full enzyme accessibility and high activation signal surge upon the enzyme activity. Using a colon cancer mouse model, the probe demonstrated selective FL activation at tumor sites with 3-fold signal enhancement in 10 min. Optical phantom experiments confirmed the advantages of the NIR-II probe over conventional dyes in the first near-infrared region.
authors.forename: Sanghwa
authors.initials: S
authors.lastname: Jeong
authors.forename: Jaejung
authors.initials: J
authors.lastname: Song
authors.forename: Wonseok
authors.initials: W
authors.lastname: Lee
authors.affiliation: Asan Institute for Life Sciences, Asan Medical Center , 88 Olympic-ro, 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.
authors.forename: Yeon Mi
authors.initials: YM
authors.lastname: Ryu
authors.forename: Yebin
authors.initials: Y
authors.lastname: Jung
authors.affiliation: Asan Institute for Life Sciences, Asan Medical Center , 88 Olympic-ro, 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.|Department of Convergence Medicine, University of Ulsan College of Medicine , 88 Olympic-ro, 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.
authors.forename: Sang-Yeob
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Civil and Environmental Engineering, Korea Army Academy at Young-cheon , Yeongcheon-si, Gyeongsangbuk-do South Korea.
authors.forename: Kangwook
authors.initials: K
authors.lastname: Kim
authors.forename: Seong Cheol
authors.initials: SC
authors.lastname: Hong
authors.affiliation: Asan Institute for Life Sciences, Asan Medical Center , 88 Olympic-ro, 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.|Department of Convergence Medicine, University of Ulsan College of Medicine , 88 Olympic-ro, 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.|Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine , 88 Olympic-ro, 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Myung
authors.forename: Sungjee
authors.identifier: 0000-0002-1289-1926
authors.initials: S
authors.lastname: Kim
keywords: Second near-infrared window; activatable probe; cancer microenvironment; molecular imaging; quantum dot