Better Hearing is Better Seeing: Molecular Photoacoustic Contrast Agents

The photoacoustic effect-the generation of a sound wave upon absorption of light by a sample-was developed over the past decades into photoacoustic imaging (PAI), and related technologies. These imaging modalities combine the advantages of optical imaging techniques (high resolution) with those of ultrasonic imaging (deep imaging depth). The light absorption by a tissue sample can be because of endogenous absorbers (such as hemoglobin or melanins). Alternatively-and most advantageously-is the use of exogenous dyes as contrast agents. Borg and Rochford present in this Journal (Photochem. Photobiol., 2018, https://doi.org/10.1111/php.12967) a comprehensive review of molecular dyes reported as contrast agents for PAI, referred to as molecular photoacoustic contrast agents (MPACs). Highlighted here is PAI as a most promising biomedical imaging modality and the importance of the rational development of novel, high-efficiency MPACs, an endeavor for which Borg and Rochford provided an excellent resource for novices and experts in the field, and anyone else interested in bioimaging or the interaction of light with chromophores.