title: Functional computer-to-plate near-infrared absorbers as highly efficient photoacoustic dyes.
abstract: Photoacoustic imaging (PAI) is an emerging modality in biomedical imaging. Photoacoustic effect is the basis for PAI, where a photoacoustic contrast agent absorbs optical pulses to initiate localized heating and rapid thermal expansion, thus generating thermoelastic stress waves. Therefore, ideal PAI dyes should have strong NIR light absorbance and high light-heat conversion efficiency. However, most current low molecular weight organic PAI contrast agents are fluorescent dyes, where the light-heat conversion efficiency is dramatically impaired due to the energy loss by fluorescence emission. Herein, we report a series of highly efficient photoacoustic dyes with COOH, NH2 and NHS ester functionalities, from an inexpensive industrial computer-to-plate NIR absorber (IR830 p-toluenesulfonate) that has a strong NIR absorbance but an extremely low fluorescence emission. In vitro and in vivo studies show that the functional IR830 dyes have low cytotoxicity, and are 2.1 folds brighter in photoacoustic imaging than traditional photoacoustic dye indocyanine green (ICG). The Lowest Limit of Quantification of the IR830 series dyes is as low as the 1/7 of that of ICG. These indicate that the functional IR830 dyes have great potential as highly efficient photoacoustic dyes.
  
  
  
  Photoacoustic imaging (PAI) is an emerging modality in biomedical imaging. Ideal PAI dyes should have strong NIR absorbance and high light-heat conversion efficiency. However, most current low molecular weight organic PAI contrast agents are fluorescent dyes, where the light-heat conversion efficiency is dramatically impaired due to the energy loss by fluorescence emission. Herein we report a series of highly efficient functional photoacoustic dyes from an inexpensive industrial computer-to-plate NIR absorber (IR830) that has a strong NIR absorbance but an extremely low fluorescence emission. The functional IR830 dyes show low cytotoxicity, much brighter in photoacoustic imaging than traditional photoacoustic dye indocyanine green. These indicate that the functional IR830 dyes have great potential as highly efficient photoacoustic dyes.
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China; College of Chemistry, Northeast Normal University, Changchun 130024, PR China.
authors.forename: Yuewei
authors.initials: Y
authors.lastname: Niu
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Wantong
authors.initials: W
authors.lastname: Song
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address: ztang@ciac.ac.cn.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Tang
authors.affiliation: College of Chemistry, Northeast Normal University, Changchun 130024, PR China. Electronic address: dengmx330@nenu.edu.cn.
authors.forename: Mingxiao
authors.initials: M
authors.lastname: Deng
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Xuesi
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D016923:Cell Death; D002460:Cell Line; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D061088:Photoacoustic Techniques / Q000379:methods*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes
keywords: Contrast agent; Dye; NIR; Photoacoustic imaging