Fluorescent gold nanoprobe sensitive to intracellular reactive oxygen species

Gold nanoprobes immobilized with fluorescein-hyaluronic acid (HA) conjugates are fabricated and utilized for monitoring intracellular reactive oxygen species (ROS) generation in live cells via nanoparticle surface energy ransfer. A bio-inspired adhesive molecule, dopamine, is used to robustly endimmobilize HA onto the surface of gold nanoparticles (AuNPs) for securing intracellular stability against glutathione. ROS induces cleavage and fragmentation of the HA chains immobilized on the surface of the AuNPs allows rapid and specific detection of intracellular ROS by emitting strong fluorescence-recovery signals. In particular, fluorescence-quenched gold nanoprobes exhibit selective and dose-dependent fluorescence-recovery signals upon exposure to certain oxygen species such as superoxide anion (O ₂.^-) and hydroxyl radical (.OH). The fluorescent gold nanoprobe is usefully exploited for real-time intracellular ROS detection and antioxidant screening assay, and has exciting potential for various biomedical applications as a new class of ROS imaging probes.