Organic Semiconducting Nanoparticles as Efficient Photoacoustic Agents for Lightening Early Thrombus and Monitoring Thrombolysis in Living Mice

Acute venous thrombosis is prevalent and potentially fatal. Accurate diagnosis of early thrombus is needed for patients in timely clinical intervention to prevent life-threatening conditions. Photoacoustic imaging (PAI) with excellent spatial resolution and high optical contrast shows more promise for this purpose. However, its application is dramatically limited by its signal-off effect on thrombus because of the ischemia in thrombus which lacks the endogenous photoacoustic (PA) signal of hemoglobin. To address this dilemma, we herein report the feasibility of using organic semiconducting nanoparticles (NPs) for contrast-enhanced PAI of thrombus in living mice. An organic semiconducting NP, self-assembled by amphiphilic perylene-3,4,9,10-tetracarboxylic diimide (PDI) molecules, is chemically modified with cyclic Arg-Gly-Asp (cRGD) peptides as a PA contrast agent (cRGD-PDI NPs) for selectively lightening early thrombus. cRGD-PDI NPs presents high PA intensity, good stability in light and serum, and suffic...