Dual Fluorescent- and Isotopic-Labelled Self-Assembling Vancomycin for in vivo Imaging of Bacterial Infections

The increase of bacterial resistance demands rapid and accurate diagnosis of bacterial infections. Biosurface-induced supramolecular assembly for diagnosis and therapy has received little attention in detecting bacterial infections. Herein we present a dual fluorescent-nuclear probe based on self-assembly of vancomycin (Van) on Gram-positive bacteria for imaging bacterial infection. A Van- and rhodamine-modified peptide derivative (Rho-FF-Van), as the imaging agent, binds to the terminal peptide of the methicillin-resistant staphylococcus aureus (MRSA) and self-assembles to form nanoaggregates on the surface of MRSA. In an in vivo myositis model, Rho-FF-Van results in a significant increased fluorescence signal at the MRSA infected site. Radiolabeled with iodine-125, Rho-FF-Van shows strong radioactive signal in the MRSA-infected lungs in a murine model. This novel dual fluorescent and nuclear probe promises a new way for in vivo imaging of bacterial infections.