NIR-? Fluorescence Imaging For Theranostics Of Urological Diseases

The second near-infrared region(NIR-II,1000 nm ~1700 nm)fluorescence imaging has higher imaging resolution,penetration depth,and signal-to-noise ratio compared with the visible light(400 nm~700 nm)and near-infrared first region(NIR-I,750~900 nm)that are widely used in biomedical research and clinical applications.Therefore,large depth imaging based on the NIR-II fluorescence imaging and photo-thermal therapy under NIR-IIb imaging guidance have become research hotspots in the field of biomedicine in recent years.Herein,we conducted a study on the feasibility of NIR-II fluorescence in the diagnosis and treatment of urological diseases.Two mainly study sections are as follows:In the first section of the study,we first detected the fluorescence emission spectrum of a clinically certified fluorescent dye methylene blue(MB)and found MB had an ideal NIR-II fluorescence signal in addition to the widely recognized NIR-I fluorescence signal for the first time.A series of optical characterization experiments and in vitro simulation experiments were conducted to initially confirm that MB NIR-II fluorescence imaging has obvious imaging advantages over MB NIR-I fluorescence.Subsequently,etrograde cystography,excretory urography,intraoperative ureteral identification further verified that MB NIR-II fluorescence imaging has obvious advantages over MB NIR-I fluorescence,and effective renal functional imaging was also achieved based on MB NIR-II fluorescence imaging.These results demonstrated that MB assisted NIR-II fluorescence imaging holds great promise for invasive/noninvasive structural imaging of the urinary system clinically and investigation of renal function in animal models preclinically.In the second section of the study,we screened a variety of NIR-II fluorescent probes and found that a new semiconductor polymer nanoparticles L1057 had an ideal NIR-IIb fluorescence effect.Since NIIR-IIb is a more ideal sub-window in NIR-II,we investigated the application of L1057 in NIR-IIb in vivo imaging after we completed a series of optical characterization and biocompatibility experiments on L1057.Whole-body vascular imaging,non-invasive transcranial cerebral angiography,gastrointestinal imaging and bladder tumor imaging comparison experiment were conducted in conventional NIR-II window and NIR-IIb window,and bioimaging using L1057 in NIR-IIb window was verified achieved higher imaging resolution,penetration depth,and signal-to-noise ratio compared with that in NIR-II window.Moreover,we also utilized L1057 to achieve effective photothermal treatment of mouse subcutaneous bladder cancer transplantation tumor under the guidance of L1057 NIR-IIb imaging,owing to its excellent photothermal effect.This part of the study lays a new theoretical foundation for the application of NIR-IIb fluorescence imaging in biomedical research and clinical applications and also provides new ideas for the treatment of bladder tumors guided by imaging.