High-efficiency FRET-enhanced photoacoustic probes for in vivo tumor imaging

Abstract

Photoacoustic imaging can provide high-resolution and high-contrast image under unprecedented depth compared with pure optical imaging techniques by making use of laser-induced ultrasound waves. Although a series of absorption-enhanced optical contrast agents for photoacoustic imaging were developed, the probe with fully conversion from absorbed light energy to acoustic energy has not been achieved so far. Here we develop a high-efficiency photoacoustic probes with fluorescence resonance energy transfer (FRET) effect for enhancement of nonradiative energy. Graphene oxide (GO) binding optical dyes (GO-dyes) were achieved to show highly fluorescence quenching and violently increased photoacoustic signal intensity. GO-dyes were constructed and testified for multi-spectral photoacoustic imaging. As a representative probe, GO-Cy7 nanoparticles were used to validate the feasibility of photoacoustic tumor molecular imaging in vivo. Our work demonstrated a new approach to construct high-efficiency FRET-enhanced multi-spectrum probes for photoacoustic molecular imaging.