Boosting NIR-II Luminescence and Antiprotein Adsorption of Gold Nanoclusters via Charge Complementary Ligands for Acute Kidney Injury Diagnosis and Sentinel Lymph Node Imaging

Gold nanoclusters (Au NCs), as an emerging class of luminescent materials, hold great promise for diverse applications. However, their low near-infrared (NIR) luminescence quantum yields (QYs) have limited their bioimaging application. Herein, we present a novel strategy to enhance the luminescence, stability, and antiprotein adsorption of Au NCs through charge complementarity of ligands. Specifically, we designed Au-ODPCA NCs with zwitterionic ligands achieving a remarkably high NIR-II (1050 nm) QY of 3.8%. Through systematic study, we demonstrated that the emission enhancement originated from the charge complementarity of ligands, which increases the rigidity of the Au-ligand complex, thereby boosting the emission. The zwitterionic ligand-capped Au NCs not only exhibited enhanced NIR-II luminescence but also demonstrated excellent antiprotein adsorption properties, allowing for acute kidney injury (AKI) diagnosis and sentinel lymph node imaging.