In vitro and in vivo NIR fluorescence lifetime imaging with a time-gated SPAD camera

Jason T. Smith, Alena Rudkouskaya, Shan Gao, Juhi M. Gupta, Arin Ulku, Claudio Bruschini, Edoardo Charbon, Shimon Weiss, Margarida Barroso, Xavier Intes, Xavier Michalet

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Near-infrared (NIR) fluorescence lifetime imaging (FLI) provides a unique contrast mechanism to monitor biological parameters and molecular events in vivo. Single-photon avalanche diode (SPAD) cameras have been recently demonstrated in FLI microscopy (FLIM) applications, but their suitability for in vivo macroscopic FLI (MFLI) in deep tissues remains to be demonstrated. Herein, we report in vivo NIR MFLI measurement with SwissSPAD2, a large time-gated SPAD camera. We first benchmark its performance in well-controlled in vitro experiments, ranging from monitoring environmental effects on fluorescence lifetime, to quantifying Förster resonant energy transfer (FRET) between dyes. Next, we use it for in vivo studies of target-drug engagement in live and intact tumor xenografts using FRET. Information obtained with SwissSPAD2 was successfully compared to that obtained with a gated intensified charge-coupled device (ICCD) camera, using two different approaches. Our results demonstrate that SPAD cameras offer a powerful technology for in vivo preclinical applications in the NIR window.

Original languageEnglish
Pages (from-to)532-544
Number of pages13
Issue number5
StatePublished - May 2022
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement


Funding. U.S. Department of Energy (DE-SC0020338); National Institutes of Health (R01CA207725, R01CA237267, R01CA250636); UCLA Jonsson Comprehensive Cancer Center Seed Grant Program; Swiss National Science Foundation.

FundersFunder number
National Institutes of HealthR01CA237267, R01CA207725, R01CA250636
U.S. Department of EnergyDE-SC0020338
University of California, Los Angeles
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung


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