Editorial overview: Molecular imaging for seeing chemistry in biology.

The quest for better understanding of complex biosystems, especially their heterogeneity nature and dynamics, has been pushing researchers to continuously develop new molecular imaging technologies. Albeit molecular imaging has evolved to be a very inclusive field, there are two grand challenges from chemical biologists’ perspective. First, how to directly see the chemistry (contents, flux, conversions, and dynamics) in living systems? Second, how to integrate the knowledge across multiple scales, from atomic structures to whole bodies, through integrated approaches of imaging? On one hand, a major theme in the field is to develop new probes, both chemically synthetic and genetically encoded, with superior properties including better stability, improved specificity, higher sensitivity, and lower invasiveness. On the other hand, new imaging modalities along with the engineering and instrumentation, always bring new insights to decipher the complex yet robust bioprocesses through new data that never been acquired before. In this issue of Current Opinion in Chemical Biology, we present seven reviews that highlight some of the recent efforts from chemists and biologists to address the grand challenges of molecular imaging.