Triazole-derivatized near-infrared cyanine dyes enable local functional fluorescent imaging of ocular inflammation

Chloe N. Thomas, Nada Alfahad, Nicholas Capewell, Jamie Cowley, Eleanor Hickman, Antonio Fernandez, Neale Harrison, Omar S. Qureshi, Naomi Bennett, Nicholas M. Barnes, Andrew D. Dick, Colin J. Chu, Xiaoxuan Liu, Alastair K. Denniston, Marc Vendrell, Lisa J. Hill

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Near-infrared (NIR) chemical fluorophores are promising tools for in-vivo imaging in real time but often succumb to rapid photodegradation. Indocyanine green (ICG) is the only NIR dye with regulatory approval for ocular imaging in humans; however, ICG, when employed for applications such as labelling immune cells, has limited sensitivity and does not allow precise detection of specific inflammatory events, for example leukocyte recruitment during uveitic flare-ups. We investigated the potential use of photostable novel triazole NIR cyanine
(TNC) dyes for detecting and characterising activated T-cell activity within the eye. Three TNC dyes were evaluated for ocular cytotoxicity in-vitro using a MTT assay and optimised concentrations for intraocular detection within ex-vivo porcine eyes after topical application or intracameral injections of the dyes. TNC labelled
T-cell tracking experiments and mechanistic studies were also performed in-vitro. TNC-1 and TNC-2 dyes exhibited greater fluorescence intensity than ICG at 10 μM, whereas TNC-3 was only detectable at 100 μM within the porcine eye. TNC dyes did not demonstrate any ocular cell toxicity at working concentrations of 10 μM.
CD4+T-cells labelled with TNC-1 or TNC-2 were detected within the porcine eye, with TNC-1 being brighter than TNC-2. Detection of TNC-1 and TNC-2 into CD4+T-cells was prevented by prior incubation with dynole 34–2 (50 μM), suggesting active uptake of these dyes via dynamin-dependent processes. The present study provides evi-dence that TNC dyes are suitable to detect activated CD4+T-cells within the eye with potential as a diagnostic marker for ocular inflammatory diseases.
Original languageEnglish
Article number114623
Number of pages11
JournalBiosensors and Bioelectronics
Publication statusPublished - 13 Aug 2022

Keywords / Materials (for Non-textual outputs)

  • near-infrared
  • fluorophores
  • cyanine
  • uveitis
  • optical coherence tomography
  • leukocytes


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