Ultra-Fast Fluorescence Imaging in Vivo with Conjugated Polymer   Fluorophores in the Second Near-Infrared Window
  In vivo fluorescence imaging in the second near-infrared window (1.0-1.7 microns) can afford deep tissue penetration and high spatial resolution, owing to the reduced scattering of long-wavelength photons. Here, we synthesize a series of low-bandgap donor/acceptor copolymers with tunable emission wavelengths of 1050-1350 nm in this window. Non-covalent functionalization with phospholipid-polyethylene glycol results in water-soluble and biocompatible polymeric nanoparticles, allowing for live cell molecular imaging at > 1000 nm with polymer fluorophores for the first time. Importantly, the high quantum yield of the polymer allows for in vivo, deep-tissue and ultrafast imaging of mouse arterial blood flow with an unprecedented frame rate of > 25 frames per second. The high time resolution results in spatially and time resolved imaging of the blood flow pattern in cardiogram waveform over a single cardiac cycle (~ 200 ms) of a mouse, which has not been observed with fluorescence imaging in this window before. 
Guosong Hong, Yingping Zou, Alexander L. Antaris, Shuo Diao, Di Wu,   Kai Cheng, Xiaodong Zhang, Changxin Chen, Bo Liu, Yueh...
physics.bio-ph physics.chem-ph physics.med-ph physics.optics