NIR Autofluorescence: Molecular Origins and Emerging Clinical Applications

The intrinsic fluorescence of many biomolecules is the main source of background noise in fluorescence bioimaging. Autofluorescence is less significant in the near infrared (NIR) than in the visible, as fewer biological components emit in this spectral range. While this advantage has attracted interest for in vivo imaging of whole tissues, autofluorescence can still complicate the detection of exogenous contrast agents and reduce the signal-to-noise ratio of the resulting fluorescence images. However, NIR autofluorescence is not only a source of undesirable noise, but it also conveys information about the state of tissues that can be exploited for diagnostic purposes. In this chapter, we discuss the issue of NIR autofluorescence from both perspectives.