Glutathione Triggered Near Infrared Fluorescence Imaging-guided Chemotherapy by Cyanine Conjugated Polypeptide

摘要： Precise detection of tumor environment for cancer diagnosis was strongly demanded for further therapies. Here, a redox-responsive fluorescence switch off/on system PCQ was designed and synthesized conjugated with near infrared (NIR) cyanine dyes (Cy5.5) and relevant quencher (FQ) in mixed polymeric micelles (PCy and PFQ). The mixed PCQ micelles was prepared with two kinds of polymer with poly (oligo (ethylene glycol) methacrylate) (POEGMA) as the hydrophilic shell, in which fluorescence emission was quenched by fluorescence resonance energy transfer (FRET) effect. The FQ was conjugated with POEGMA by disulfide linkage, which could be broke with redox environment such as high glutathione (GSH) concentration in tumor cells. After the PCQ micelles got into tumor cells, PFQ block in PCQ would be disassembled to recompose PCy micelles. During that process, drugs like doxorubicin (DOX) could be loaded inside and formed PCQ@DOX nanoparticles and then released for accurate NIR bioimaging and drug delivery instantly.