Visualizing Oxazine 4 nerve-specific fluorescence ex vivo in frozen tissue sections

Connor W. Barth, Summer L. Gibbs

Research output: Chapter in Book/Report/Conference proceedingConference contribution

10 Scopus citations


Nerve damage plagues surgical outcomes and remains a major burden for patients, surgeons, and the healthcare system. Fluorescence image-guided surgery using nerve specific small molecule fluorophores offers a solution to diminish surgical nerve damage through improved intraoperative nerve identification and visualization. Oxazine 4 has shown superior nerve specificity in initial testing in vivo, while exhibiting a red shifted excitation and emission spectra compared to other nerve-specific fluorophores. However, Oxazine 4 does not exhibit near-infrared (NIR) excitation and emission, which would be ideal to improve penetration depth and nerve signal to background ratios for in vivo imaging. Successful development of a NIR nerve-specific fluorophore will require understanding of the molecular target of fluorophore nerve specificity. While previous small molecule nerve-specific fluorophores have demonstrated excellent ex vivo nerve specificity, Oxazine 4 ex vivo nerve specific fluorescence has been difficult to visualize. In the present study, we examined each step of the ex vivo fluorescence microscopy sample preparation procedure to discover how in vivo nerve-specific fluorescence is changed during ex vivo tissue sample preparation. Through step-by-step examination we found that Oxazine 4 fluorescence was significantly diminished by washing and mounting tissue sections for microscopy. A method to preserve Oxazine 4 nerve specific fluorescence ex vivo was determined, which can be utilized for visualization by fluorescence microscopy.

Original languageEnglish (US)
Title of host publicationMolecular-Guided Surgery
Subtitle of host publicationMolecules, Devices, and Applications II
EditorsBrian W. Pogue, Sylvain Gioux
ISBN (Electronic)9781628419306
StatePublished - 2016
EventMolecular-Guided Surgery: Molecules, Devices, and Applications II - San Francisco, United States
Duration: Feb 13 2016Feb 14 2016

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherMolecular-Guided Surgery: Molecules, Devices, and Applications II
Country/TerritoryUnited States
CitySan Francisco


  • ex vivo tissue analysis
  • fluorescence image-guided surgery
  • fluorophore development
  • near-infrared (NIR)
  • nerve-specific fluorophore

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging


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