NIR-II Excitable Conjugated Polymer Dots with Bright NIR-I Emission for Deep In Vivo Two-Photon Brain Imaging Through Intact Skull
Wang, Shaowei Liu, Jie Feng, Guangxue Ng, Lai Guan Liu, Bin
Liu, Jie
Ng, Lai Guan
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Alternative Title
Abstract
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Methods for noninvasive brain imaging are highly desirable to study brain structures in neuroscience. Two-photon fluorescence microscopy (2PFM) with near-infrared (NIR) light excitation is a relatively noninvasive approach commonly used to study brain with high spatial resolution and large imaging depth. However, most of the current studies require cranial window implantation or skull-thinning methods due to attenuation of excitation light. 2PFM through intact mouse skull is challenging due to strong scattering induced by skull bone. Herein, NIR-II light excitable single-chain conjugated polymer dots (CPdots) with bright fluorescence in NIR-I region (peak at ≈725 nm and quantum yield of 20.6 ± 1.0%) are developed for deep in vivo two-photon fluorescence (2PF) imaging of intact mouse brain. The synthesized CPdots exhibit good biocompatibility, high photostability, and large two-photon absorption cross section. The CPdots allow 2PF images acquired upon excitation at 800, 1040 and 1200 nm with the highest signal-to-background ratio of 208 demonstrated for 1200 nm excitation. Moreover, a 3D reconstruction of the brain blood vessel network is obtained with a large vertical depth of 400 µm through intact skull. This work demonstrates great potential of bright NIR fluorophores for in vivo deep tissue imaging.
Keywords
Science & Technology, Physical Sciences, Technology, Chemistry, Multidisciplinary, Chemistry, Physical, Nanoscience & Nanotechnology, Materials Science, Multidisciplinary, Physics, Applied, Physics, Condensed Matter, Chemistry, Science & Technology - Other Topics, Materials Science, Physics, brain imaging, conjugated polymer, deep tissue, NIR-II excitation, two-photon, BONE-MARROW, LONG-TERM, 1040 NM, TISSUE, NANOPARTICLES, MICROSCOPY, ABSORPTION, WINDOW, MULTIPHOTON, RESOLUTION
Source Title
ADVANCED FUNCTIONAL MATERIALS
Publisher
WILEY-V C H VERLAG GMBH
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Date
2019-04-11
DOI
10.1002/adfm.201808365
Type
Article