title: Near-Infrared Squaraine Dye Encapsulated Micelles for in Vivo Fluorescence and Photoacoustic Bimodal Imaging.
abstract: Combined near-infrared (NIR) fluorescence and photoacoustic imaging techniques present promising capabilities for noninvasive visualization of biological structures. Development of bimodal noninvasive optical imaging approaches by combining NIR fluorescence and photoacoustic tomography demands suitable NIR-active exogenous contrast agents. If the aggregation and photobleaching are prevented, squaraine dyes are ideal candidates for fluorescence and photoacoustic imaging. Herein, we report rational selection, preparation, and micelle encapsulation of an NIR-absorbing squaraine dye (D1) for in vivo fluorescence and photoacoustic bimodal imaging. D1 was encapsulated inside micelles constructed from a biocompatible nonionic surfactant (Pluoronic F-127) to obtain D1-encapsulated micelles (D1(micelle)) in aqueous conditions. The micelle encapsulation retains both the photophysical features and chemical stability of D1. D1(micelle) exhibits high photostability and low cytotoxicity in biological conditions. Unique properties of D1(micelle) in the NIR window of 800-900 nm enable the development of a squaraine-based exogenous contrast agent for fluorescence and photoacoustic bimodal imaging above 820 nm. In vivo imaging using D1(micelle), as demonstrated by fluorescence and photoacoustic tomography experiments in live mice, shows contrast-enhanced deep tissue imaging capability. The usage of D1(micelle) proven by preclinical experiments in rodents reveals its excellent applicability for NIR fluorescence and photoacoustic bimodal imaging.
authors.affiliation: †Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
authors.forename: Sivaramapanicker
authors.initials: S
authors.lastname: Sreejith
authors.affiliation: †Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
authors.forename: James
authors.initials: J
authors.lastname: Joseph
authors.affiliation: ‡SingHealth Experimental Medicine Centre, Singapore Health Services Pte. Ltd., 20 College Road, 169856, Singapore.
authors.forename: Manjing
authors.initials: M
authors.lastname: Lin
authors.affiliation: §School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore.
authors.forename: Nishanth Venugopal
authors.initials: NV
authors.lastname: Menon
authors.affiliation: †Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
authors.forename: Parijat
authors.initials: P
authors.lastname: Borah
authors.affiliation: †Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
authors.forename: Hao Jun
authors.initials: HJ
authors.lastname: Ng
authors.affiliation: †Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
authors.forename: Yun Xian
authors.initials: YX
authors.lastname: Loong
authors.affiliation: §School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore.
authors.forename: Yuejun
authors.initials: Y
authors.lastname: Kang
authors.forename: Sidney Wing-Kwong
authors.initials: SW
authors.lastname: Yu
authors.affiliation: †Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.|#School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival; D003503:Cyclobutanes / Q000737:chemistry*; D005260:Female; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D008823:Micelles; D057054:Molecular Imaging / Q000379:methods*; D061848:Optical Imaging; D010636:Phenols / Q000737:chemistry*; D061088:Photoacoustic Techniques
chemical_list: D003503:Cyclobutanes; D005456:Fluorescent Dyes; D008823:Micelles; D010636:Phenols; C480596:squaraine
keywords: bioimaging; fluorescence tomography; micelles; photoacoustic tomography; squaraine dye