Renal Clearable Ultraminiature Chain-like Gold Nanoparticle Clusters for Multimodal Molecular Imaging of Choroidal Neovascularization.

Currently available gold nanoparticles (GNPs) typically accumulate in the liver and spleen, leading to concerns for their long-term biosafety. To address this long-standing problem, we developed ultraminiature chain-like gold nanoparticle clusters (GNCs). Via self-assembly of 7-8 nm GNP monomers, GNCs provide red-shifted optical absorption and scattering contrast in the near-infrared window. After disassembly, GNCs turn back to GNPs with a size smaller than the renal glomerular filtration size cutoff, allowing their excretion via urine. Our one-month longitudinal study in a rabbit eye model demonstrated that GNCs facilitate multimodal molecular imaging of choroidal neovascularization (CNV) in vivo, non-invasively, with excellent sensitivity and spatial resolution. GNCs targeting α v β 3  integrins enhanced photoacoustic and OCT signals from CNV by 25.3-fold and 150%, respectively. With excellent biosafety and biocompatibility demonstrated, GNCs render a first-of-its-kind nanoplatform for biomedical imaging. This article is protected by copyright. All rights reserved.