Hyaluronic Acid−Quantum Dot Conjugates for <i>In Vivo</i> Lymphatic Vessel Imaging

A simple and novel electrostatic coupling method is reported, which provides a hyaluronic acid−quantum dot conjugate (HA−QD) that is colloidally stable and size-tunable from 50 to 120 nm. The HA−QDs show cancer targeting efficiency, which suggests diagnostic and imaging applications. The conjugates are also demonstrated for the fluorescence staining capability for lymphatic vessels <i>in vitro</i> and <i>in vivo</i>. Using the HA−QDs in a small animal model, lymphatic vessels are visualized real-time <i>in vivo</i> for days. Comprehensive cytotoxicity evaluations are made for the conjugates and the unconjugated counterpart. The HA−QDs showcase the potentials toward cancer imaging and real-time visualization of changes in lymphatic vessels such as lymphangiogenesis.