To overcome the most significant deficiencies of conventional and contrast-enhanced imaging – low contrast and sensitivity, we introduced a new class of contrast agents – nanometer scale particles that are capable of systemic delivery and penetration into tissue, and then, once they reach the target site, generating sufficient photoacoustic and ultrasound contrast upon user-controlled optical activation. These contrast agents – perfluorocarbon nanodroplets, silica nanoparticles doped with optically modulatable photoabsorbers, and gas-generating plasmonic nanoparticles covered by azide compounds, are stable at physiological temperatures, biocompatible, and nearly monodisperse in size. Given the unique properties of these particles, our imaging approach is drastically different from that of conventional imaging. Specifically, deterministically time-varying photoacoustic or ultrasound signals from nanoparticles can be demodulated to selectively recover high contrast, background-free photoacoustic and ultrasound images. Furthermore, these particles allow for multiplexed molecular imaging by permitting user-controlled laser triggering of distinct color-coded populations of contrast agents via tuning of the incident laser irradiation to match optical absorption of the particles. This presentation, via examples, will discuss synthesis and optimization of the optically modulatable contrast agents, and their applications in diagnostic imaging and image-guided therapy.

Optically modulatable contrast agents for background-free photoacoustic and ultrasound imaging

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.