Professor Zhang Fan's research team of Fudan University uses the assembly and disassembly of NIR probe in vivo to improve the optical imaging effect

Recently, Professor Zhang Fan, Department of chemistry, Fudan University, made use of supramolecular assembly to realize the efficient aggregation of near-infrared nanoprobes at tumor sites, which improved the imaging signal of tumor sites At the same time, the team achieved controlled depolymerization in the liver through near-infrared light regulation, effectively reducing the background signal of imaging and the potential biological toxicity brought by particle deposition Relevant research results were published in advanced materials (DOI: 10.1002 / ADMA 201804982) under the title of "supremely engineered nir-ii and upconversion nanoparticles invivo assembly and disassembly to improve bioimaging" Zhao Mengyao, a doctoral student of Professor Zhang Fan's research team, is the first author of the paper Nanoparticles, as imaging contrast agents, can be deposited in tumor site through enhanced infiltration and retention effect (EPR effect) In order to improve the concentration in tumor site, the in vivo aggregation of nanoparticles has been widely used in various imaging methods, such as nuclear magnetic imaging, photoacoustic imaging and so on However, most nanoparticles will be captured by reticuloendothelial system, such as liver, and non-specific aggregation will occur in vivo, which will cause high background signal and irreversible long-term toxicity Therefore, the controllable de assembly of nanoparticles in vivo is an urgent problem (a) Through the schematic diagram of supramolecular structure aggregation of azobenzene cyclodextrin nanoparticles, the 1060 nm light emitted by down conversion nanoparticles can be used for near-infrared two zone imaging; (b) 980 nm near-infrared light-mediated depolymerization schematic diagram of nanoparticles; (c) tumor site aggregation and liver site depolymerization schematic diagram of nanoparticles (source: Advanced Materials) in view of the existing problems, Professor Zhang Fan's research team constructed the aggregation system in the body of nanoparticles by using the host guest supramolecular structure of azobenzene cyclodextrin, and excited the upconversion nanoparticles by near-infrared light (980 nm) with deep penetration, so that they can be converted into visible light to trigger azobenzene- The dissociation between cyclodextrins can realize the in vivo depolymerization of nanoparticles At the same time, the team realized high-efficiency imaging of animals in vivo by using near-infrared second window (nir-ii, 1000-1400nm) rare earth nano probe (1060nm emission) The system can be widely used in other imaging and treatment fields This work has been greatly supported by the Department of chemistry of Fudan University, the State Key Laboratory of polymer engineering, the Advanced Materials Laboratory of Fudan University, the state key R & D project, the excellent youth fund of the National Natural Science Foundation, and the key basic research project of Shanghai Science and Technology Commission.