High-Resolution Shortwave Infrared Imaging of Vascular Disorders Using Gold Nanoclusters.

We synthesized a generation of water-soluble, atomically precise gold nanoclusters (Au NCs) with anisotropic surface containing short dithiol pegylated chain (AuMHA/TDT). These AuMHA/TDT exhibit a high brightness (QY∼6%) in the shortwave infrared (SWIR) spectrum with a detection above 1250 nm. Furthermore, they show an extended half-life in blood (t = 19.54 ±0.05 h) and a very weak accumulation in organs. We also developed a non-invasive, whole-body vascular imaging system in the SWIR window with high-resolution, benefiting from a series of Monte Carlo image processing of the images. The imaging process enabled to improve contrast by one order of magnitude and enhance by 59% the spatial resolution. After systemic administration of these nanoprobes in mice, we can quantify vessel complexity in depth (>4mm) allowing to detect very subtle vascular disorders non-invasively in bone morphogenetic 9 (Bmp9) deficient mice. The combination of these anisotropic surface charged gold nanoclusters plus an improved SWIR imaging device allows then a precise mapping at high resolution and in depth of the organization of the vascular network in live animals.