Ultrafast fluorescence imaging in vivo with conjugated polymer fluorophores in the second near-infrared window

Nat Commun. 2014 Jun 20;5:4206. doi: 10.1038/ncomms5206.


In vivo fluorescence imaging in the second near-infrared window (1.0-1.7 μm) 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 1,050-1,350 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 >1,000 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arteries / physiology*
  • Mice
  • Microscopy, Atomic Force
  • Molecular Imaging / methods*
  • Molecular Structure
  • Nanoparticles*
  • Optical Imaging / methods*
  • Phospholipids
  • Polyethylene Glycols
  • Polymers / chemistry
  • Regional Blood Flow / physiology*


  • Phospholipids
  • Polymers
  • Polyethylene Glycols