{"title":"Fluorescence Imaging Using Deep-Red Indocyanine Blue, a Complementary Partner for Near-Infrared Indocyanine Green","authors":"Rananjaya S. Gamage, and , Bradley D. Smith*, ","doi":"10.1021/cbmi.4c00008","DOIUrl":null,"url":null,"abstract":"<p >Indocyanine Blue (ICB) is the deep-red pentamethine analogue of the widely used clinical near-infrared heptamethine cyanine dye Indocyanine Green (ICG). The two fluorophores have the same number of functional groups and molecular charge and vary only by a single vinylene unit in the polymethine chain, which produces a predictable difference in spectral and physicochemical properties. We find that the two dyes can be employed as a complementary pair in diverse types of fundamental and applied fluorescence imaging experiments. A fundamental fluorescence spectroscopy study used ICB and ICG to test a recently proposed Förster Resonance Energy Transfer (FRET) mechanism for enhanced fluorescence brightness in heavy water (D<sub>2</sub>O). The results support two important corollaries of the proposal: (a) the strategy of using heavy water to increase the brightness of fluorescent dyes for microscopy or imaging is most effective when the dye emission band is above 650 nm, and (b) the magnitude of the heavy water florescence enhancement effect for near-infrared ICG is substantially diminished when the ICG surface is dehydrated due to binding by albumin protein. Two applied fluorescence imaging studies demonstrated how deep-red ICB can be combined with a near-infrared fluorophore for paired agent imaging in the same living subject. One study used dual-channel mouse imaging to visualize increased blood flow in a model of inflamed tissue, and a second mouse tumor imaging study simultaneously visualized the vasculature and cancerous tissue in separate fluorescence channels. The results suggest that ICB and ICG can be incorporated within multicolor fluorescence imaging methods for perfusion imaging and hemodynamic characterization of a wide range of diseases.</p>","PeriodicalId":53181,"journal":{"name":"Chemical & Biomedical Imaging","volume":"2 5","pages":"384–397"},"PeriodicalIF":0.0000,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/cbmi.4c00008","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical & Biomedical Imaging","FirstCategoryId":"1085","ListUrlMain":"https://pubs.acs.org/doi/10.1021/cbmi.4c00008","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Indocyanine Blue (ICB) is the deep-red pentamethine analogue of the widely used clinical near-infrared heptamethine cyanine dye Indocyanine Green (ICG). The two fluorophores have the same number of functional groups and molecular charge and vary only by a single vinylene unit in the polymethine chain, which produces a predictable difference in spectral and physicochemical properties. We find that the two dyes can be employed as a complementary pair in diverse types of fundamental and applied fluorescence imaging experiments. A fundamental fluorescence spectroscopy study used ICB and ICG to test a recently proposed Förster Resonance Energy Transfer (FRET) mechanism for enhanced fluorescence brightness in heavy water (D2O). The results support two important corollaries of the proposal: (a) the strategy of using heavy water to increase the brightness of fluorescent dyes for microscopy or imaging is most effective when the dye emission band is above 650 nm, and (b) the magnitude of the heavy water florescence enhancement effect for near-infrared ICG is substantially diminished when the ICG surface is dehydrated due to binding by albumin protein. Two applied fluorescence imaging studies demonstrated how deep-red ICB can be combined with a near-infrared fluorophore for paired agent imaging in the same living subject. One study used dual-channel mouse imaging to visualize increased blood flow in a model of inflamed tissue, and a second mouse tumor imaging study simultaneously visualized the vasculature and cancerous tissue in separate fluorescence channels. The results suggest that ICB and ICG can be incorporated within multicolor fluorescence imaging methods for perfusion imaging and hemodynamic characterization of a wide range of diseases.
期刊介绍:
Chemical & Biomedical Imaging is a peer-reviewed open access journal devoted to the publication of cutting-edge research papers on all aspects of chemical and biomedical imaging. This interdisciplinary field sits at the intersection of chemistry physics biology materials engineering and medicine. The journal aims to bring together researchers from across these disciplines to address cutting-edge challenges of fundamental research and applications.Topics of particular interest include but are not limited to:Imaging of processes and reactionsImaging of nanoscale microscale and mesoscale materialsImaging of biological interactions and interfacesSingle-molecule and cellular imagingWhole-organ and whole-body imagingMolecular imaging probes and contrast agentsBioluminescence chemiluminescence and electrochemiluminescence imagingNanophotonics and imagingChemical tools for new imaging modalitiesChemical and imaging techniques in diagnosis and therapyImaging-guided drug deliveryAI and machine learning assisted imaging