Near-infrared-persistent Luminescence/bioluminescence Imaging Tracking Of Transplanted Mesenchymal Stem Cells In Vivo

Human mesenchymal stem cells?h MSCs?with distinct characteristics is promising in the treatment of pulmonary fibrosis?PF?.However,it is still ambiguous regarding the behavior of h MSCs after transplantation,including dynamic translocation,location and survival,impeding the clinical application of h MSCs in PF.Due to their high sensitivity and facile operation,optical imaging techniques play an important role in cell imging and tracking.Whereas,impeded by relatively short lifetime,ranging from nanoseconds to microseconds,and severe background autofluorescence caused by in situ excitation,the imaging quality of traditional fluorescent probes is limited.Long persistent luminescence nanoparticles?LPLNP?have been regarded as a characteristic and powerful optical probe in bioimaging without continuous exogenous excitation.Besides,living cells can be identified simultaneously via bioluminescence imaging based on luciferase reporter gene.Herein,we develop an effective dual-labeling strategy combining endogenous bioluminescence imaging?BLI?and exogenous near-infrared-persistent luminescence?NIR-PL?imaging for in situ visualization of the transplanted stem cells.The long persistent luminescence nanoparticles?LPLNP?Zn_1.1Ga_1.8Ge_0.1O₄:Cr³⁺,Eu³⁺were selected,referring to related publications,to surveil the dynamic translocation,position and distribution of the transplanted h MSCs as long as 30 d,taking advantages of their long-lasting NIR-PL imaging ability and minimal autofluorescence background interference.And in virtue of the ability to express red-emitting firefly luciferase?Rf Luc?,the living stem cells after transplantation could be discriminated from the dead counterparts by means of BLI.This facile pattern contributes to in situ monitor of the stem cells regarding their spontaneous behavior in vivo,and therefore deepening our knowledge in the role transplanted h MSCs play in PF therapy.