Near-Infrared Squaraine Dye Encapsulated Micelles for in Vivo Fluorescence and Photoacoustic Bimodal Imaging

Sivaramapanicker Sreejith, James Joseph, Manjing Lin, Nishanth Venugopal Menon, Parijat Borah, Hao Jun Ng, Yun Xian Loong, Yuejun Kang, Sidney Wing Kwong Yu, Yanli Zhao (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

133 Citations (Scopus)


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 (D1micelle) in aqueous conditions. The micelle encapsulation retains both the photophysical features and chemical stability of D1. D1micelle exhibits high photostability and low cytotoxicity in biological conditions. Unique properties of D1micelle 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 D1micelle, as demonstrated by fluorescence and photoacoustic tomography experiments in live mice, shows contrast-enhanced deep tissue imaging capability. The usage of D1micelle proven by preclinical experiments in rodents reveals its excellent applicability for NIR fluorescence and photoacoustic bimodal imaging.

Original languageEnglish
Pages (from-to)5695-5704
Number of pages10
JournalACS Nano
Issue number6
Early online date2 Jun 2015
Publication statusPublished - 23 Jun 2015


  • bioimaging
  • fluorescence tomography
  • micelles
  • photoacoustic tomography
  • squaraine dye

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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