Practical implementation, characterization and applications of a multi-colour time-gated luminescence microscope

Lixin Zhang (1) , Xianlin Zheng (1) , Wei Deng (1) , Yiqing Lu (1) , Séverine Lechevallier (2) , Zhiqiang Ye (3) , Ewa M. Goldys (1) , Judith M. Dawes (1) , James A. Piper (1) , Jingli Yuan (3) , Marc Verelst (2) , Dayong Jin (1)

1 Macquarie University
2 CEMES - Centre d'élaboration de matériaux et d'études structurales
3 Dalian University of Technology

Time-gated luminescence microscopy using long-lifetime molecular probes can effectively eliminate autofluorescence to enable high contrast imaging. Here we investigate a new strategy of time-gated imaging for simultaneous visualisation of multiple species of microorganisms stained with long-lived complexes under low-background conditions. This is realized by imaging two pathogenic organisms (Giardia lamblia stained with a red europium probe and Cryptosporidium parvum with a green terbium probe) at UV wavelengths (320-400 nm) through synchronization of a flash lamp with high repetition rate (1 kHz) to a robust time-gating detection unit. This approach provides four times enhancement in signal-to-background ratio over non-time-gated imaging, while the average signal intensity also increases six-fold compared with that under UV LED excitation. The high sensitivity is further confirmed by imaging the single europium-doped Y2O2S nanocrystals (150 nm). We report technical details regarding the time-gating detection unit and demonstrate its compatibility with commercial epi-fluorescence microscopes, providing a valuable and convenient addition to standard laboratory equipment.

Mots clés: Molecular Imaging; chemistry; Cryptosporidium parvum; fluorescence microscopy; luminescence; procedures; ultrastructure; Europium; Luminescent Measurements; Microscopy; Fluorescence

Domaines: Physique [physics]

Lixin Zhang, Xianlin Zheng, Wei Deng, Yiqing Lu, Séverine Lechevallier, et al.. Practical implementation, characterization and applications of a multi-colour time-gated luminescence microscope. Scientific Reports, 2014, 4 (1), ⟨10.1038/srep06597⟩. ⟨hal-01760884⟩