Bromine indirubin FLIM/PLIM sensors to measure oxygen in normoxic and hypoxic PDT conditions

Photodiagnosis Photodyn Ther. 2024 Feb:45:103964. doi: 10.1016/j.pdpdt.2024.103964. Epub 2024 Jan 11.

Abstract

Background: The induction of phototoxicity during photodynamic therapy (PDT) is dependent on oxygen availability. For this reason, the development of sensors to measure oxygen and oxygen consumption is extremely important.

Approach: In this project we have used Fluorescence Lifetime imaging (FLIM) and Phosphorescence Lifetime Imaging/ delayed Fluorescence Lifetime Imaging (PLIM/dFLIM) to investigate the ability of bromine indirubin derivatives as oxygen sensors.

Results: The oxygen sensitivity of bromine indirubins was detected through PLIM/dFLIM. Moreover, we have observed, by measuring nicotinamide adenine dinucleotide (NADH) FLIM, that bromine indirubin has a significant impact on cellular metabolism by shifting the SCC-4 Cells metabolism from oxidative phosphorylation (OXPHOS) to glycolysis.

Conclusions: In conclusion, this study successfully achieves its goals and provides important insights into the use of indirubin as a potential oxygen consumption sensor with the capability to identify and differentiate between normoxic and hypoxic regions within the cells.

Keywords: Indirubin derivatives; NADH-FLIM; Oxygen consumption; PLIM; Photodynamic Therapy; TCSPC; Ultrafast techniques; dFLIM.

MeSH terms

  • Bromine
  • Humans
  • Hypoxia
  • Indoles
  • Oxygen*
  • Photochemotherapy* / methods
  • Photosensitizing Agents / pharmacology

Substances

  • Oxygen
  • Bromine
  • indirubin
  • Photosensitizing Agents
  • Indoles