Royal College of Surgeons in Ireland
BF2-azadipyrromethene fluorophores for intraoperative vital structure identification.pdf (5.04 MB)

BF2-azadipyrromethene fluorophores for intraoperative vital structure identification

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journal contribution
posted on 2023-03-29, 16:04 authored by Cathal CaulfieldCathal Caulfield, Dan WuDan Wu, Ian MillerIan Miller, Annette ByrneAnnette Byrne, Pól Mac Aonghusa, Sergiy Zhuk, Lorenzo Cinelli, Elisa Bannone, Jacques Marescaux, Sylvain Gioux, Michele Diana, Taryn L March, Alexander L Vahrmeijer, Ronan CahillRonan Cahill, Donal O'SheaDonal O'Shea

A series of mono- and bis-polyethylene glycol (PEG)-substituted BF2-azadipyrromethene fluorophores have been synthesized with emissions in the near-infrared region (700-800 nm) for the purpose of fluorescence guided intraoperative imaging; chiefly ureter imaging. The Bis-PEGylation of fluorophores resulted in higher aqueous fluorescence quantum yields, with PEG chain lengths of 2.9 to 4.6 kDa being optimal. Fluorescence ureter identification was possible in a rodent model with the preference for renal excretion notable through comparative fluorescence intensities from the ureters, kidneys and liver. Ureteral identification was also successfully performed in a larger animal porcine model under abdominal surgical conditions. Three tested doses of 0.5, 0.25 and 0.1 mg/kg all successfully identified fluorescent ureters within 20 min of administration which was sustained up to 120 min. 3-D emission heat map imaging allowed the spatial and temporal changes in intensity due to the distinctive peristaltic waves of urine being transferred from the kidneys to the bladder to be identified. As the emission of these fluorophores could be spectrally distinguished from the clinically-used perfusion dye indocyanine green, it is envisaged that their combined use could be a step towards intraoperative colour coding of different tissues. 


Irish Government Department of Business, Enterprise and Innovation’s Disruptive Technology Innovation Fund

Science Foundation Ireland grant number 17/TIDA/4936

Synthesis and Solid State Pharmaceutical Centre (SSPC) grant number 12/RC/2275_P2 f

ARC Foundation (, via the ELIOS grant

Science Foundation Ireland Research infrastructure grant 18/RI/5759 “NPIC” (



The original article is available at

Published Citation

Caulfield C. et al. BF2-azadipyrromethene fluorophores for intraoperative vital structure identification. Molecules. 2023;28(5):2167

Publication Date

25 February 2023

PubMed ID



  • Chemistry
  • Physiology and Medical Physics




  • Published Version (Version of Record)