<i>J</i>-Aggregates of Cyanine Dye for NIR-II <i>in Vivo</i> Dynamic Vascular Imaging beyond 1500 nm

TLDR

The second near‑infrared window beyond 1500 nm offers superior tissue transparency for high‑resolution in vivo imaging, yet creating organic dyes that absorb and emit in this range remains challenging. The study introduces J‑aggregates of FD‑1080 and DSPC that absorb at 1360 nm and emit at 1370 nm for NIR‑II imaging beyond 1500 nm. The J‑aggregates are formed by self‑assembly of FD‑1080 and DSPC, and their assembly dynamics were modeled by molecular‑dynamics simulations. The J‑aggregates provide high‑resolution, high signal‑to‑background imaging of brain and hindlimb vasculature beyond 1500 nm and enable in‑vivo evaluation of a clinically used hypotensor.

Abstract

Light in the second near-infrared window, especially beyond 1500 nm, shows enhanced tissue transparency for high-resolution in vivo optical bioimaging due to decreased tissue scattering, absorption, and autofluorescence. Despite some inorganic luminescent nanoparticles have been developed to improve the bioimaging around 1500 nm, it is still a great challenge to synthesize organic molecules with the absorption and emission toward this region. Here, we present J-aggregates with 1360 nm absorption and 1370 nm emission formed by self-assembly of amphiphilic cyanine dye FD-1080 and 1,2-dimyristoyl-sn-glycero-3-phosphocholine. Molecular dynamics simulations were further employed to illustrate the self-assembly process. Superior spatial resolution and high signal-to-background ratio of J-aggregates were demonstrated for noninvasive brain and hindlimb vasculature bioimaging beyond 1500 nm. The efficacy evaluation of the clinically used hypotensor is successfully achieved by high-resolution in vivo dynamic vascular imaging with J-aggregates.