The sound of drug delivery: Optoacoustic imaging in pharmacology

Optoacoustic (photoacoustic) imaging offers unique opportunities for visualizing biological function in vivo by achieving high-resolution images of optical contrast much deeper than any other optical tech-nique. The method detects ultrasound waves that are generated inside tissue by thermo-elastic expan-sion, i.e., the conversion of light absorption by tissue structures to ultrasound when the tissue is illuminated by the light of varying intensity. Listening instead of looking to light offers the major advan-tage of image formation with a resolution that obeys ultrasonic diffraction and not photon diffusion laws. While the technique has been widely used to explore contrast from endogenous photo-absorbing mole-cules, such as hemoglobin or melanin, the use of exogenous agents can extend applications to a larger range of biological and possible clinical applications, such as image-guided surgery, disease monitoring, and the evaluation of drug delivery, biodistribution, and kinetics. This review summarizes recent devel-opments in optoacoustic agents, and highlights new functions visualized and potent pharmacology appli-cations enabled with the use of external contrast agents. ?? 2022 Elsevier B.V. All rights reserved.

Automated summary

Optoacoustic imaging is a unique technique that provides high-resolution images of optical contrast for visualizing biological function in vivo. By detecting ultrasound waves generated through the conversion of light absorption to ultrasound, this method offers a range of applications in various biological and clinical fields.