scholarly journals Fluorescence lifetime imaging of upper gastrointestinal pH in vivo with a lanthanide based near-infrared τ probe

2019 ◽  
Vol 10 (15) ◽  
pp. 4227-4235 ◽  
Author(s):  
Yingying Ning ◽  
Shengming Cheng ◽  
Jing-Xiang Wang ◽  
Yi-Wei Liu ◽  
Wei Feng ◽  
...  

Lanthanide complex was successfully applied in the design of pH-responsive NIR τ probe for quantitative in vivo imaging.

2009 ◽  
Vol 11 (3) ◽  
pp. 167-177 ◽  
Author(s):  
Natalie A. Christian ◽  
Fabian Benencia ◽  
Michael C. Milone ◽  
Guizhi Li ◽  
Paul R. Frail ◽  
...  

2007 ◽  
Vol 6 (4) ◽  
pp. 7290.2007.00019 ◽  
Author(s):  
Moinuddin Hassan ◽  
Jason Riley ◽  
Victor Chernomordik ◽  
Paul Smith ◽  
Randall Pursley ◽  
...  

In this article, a fluorescence lifetime imaging system for small animals is presented. Data were collected by scanning a region of interest with a measurement head, a linear fiber array with fixed separations between a single source fiber and several detection fibers. The goal was to localize tumors and monitor their progression using specific fluorescent markers. We chose a near-infrared contrast agent, Alexa Fluor 750 (Invitrogen Corp., Carlsbad, CA). Preliminary results show that the fluorescence lifetime for this dye was sensitive to the immediate environment of the fluorophore (in particular, pH), making it a promising candidate for reporting physiologic changes around a fluorophore. To quantify the intrinsic lifetime of deeply embedded fluorophores, we performed phantom experiments to investigate the contribution of photon migration effects on observed lifetime by calculating the fluorescence intensity decay time. A previously proposed theoretical model of migration, based on random walk theory, is also substantiated by new experimental data. The developed experimental system has been used for in vivo mouse imaging with Alexa Fluor 750 contrast agent conjugated to tumor-specific antibodies (trastuzumab [Herceptin]). Three-dimensional mapping of the fluorescence lifetime indicates lower lifetime values in superficial breast cancer tumors in mice.


2021 ◽  
Author(s):  
Jason T. Smith ◽  
Alena Rudkouskaya ◽  
Shan Gao ◽  
Juhi M. Gupta ◽  
Arin Ulku ◽  
...  

Near-infrared (NIR) fluorescence lifetime imaging (FLI) provides a unique contrast mechanism to monitor biological parameters and molecular events in vivo. Single-photon avalanche photodiode (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-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.


2014 ◽  
Vol 20 (13) ◽  
pp. 3531-3539 ◽  
Author(s):  
Yasaman Ardeshirpour ◽  
Victor Chernomordik ◽  
Moinuddin Hassan ◽  
Rafal Zielinski ◽  
Jacek Capala ◽  
...  

2020 ◽  
Author(s):  
Xingbo Yang ◽  
Daniel J. Needleman

AbstractMitochondria are central to metabolism and their dysfunctions are associated with many diseases1–9. Metabolic flux, the rate of turnover of molecules through a metabolic pathway, is one of the most important quantities in metabolism, but it remains a challenge to measure spatiotemporal variations in mitochondrial metabolic fluxes in living cells. Fluorescence lifetime imaging microscopy (FLIM) of NADH is a label-free technique that is widely used to characterize the metabolic state of mitochondria in vivo10–18. However, the utility of this technique has been limited by the inability to relate FLIM measurement to the underlying metabolic activities in mitochondria. Here we show that, if properly interpreted, FLIM of NADH can be used to quantitatively measure the flux through a major mitochondrial metabolic pathway, the electron transport chain (ETC), in vivo with subcellular resolution. This result is based on the use of a coarse-grained NADH redox model, which we test in mouse oocytes subject to a wide variety of perturbations by comparing predicted fluxes to direct biochemical measurements and by self-consistency criterion. Using this method, we discovered a subcellular spatial gradient of mitochondrial metabolic flux in mouse oocytes. We showed that this subcellular variation in mitochondrial flux correlates with a corresponding subcellular variation in mitochondrial membrane potential. The developed model, and the resulting procedure for analyzing FLIM of NADH, are valid under nearly all circumstances of biological interest. Thus, this approach is a general procedure to measure metabolic fluxes dynamically in living cells, with subcellular resolution.


2018 ◽  
Vol 38 (4) ◽  
pp. 966-974 ◽  
Author(s):  
Piotr Sawosz ◽  
Stanislaw Wojtkiewicz ◽  
Michal Kacprzak ◽  
Elzbieta Zieminska ◽  
Magdalena Morawiec ◽  
...  

2020 ◽  
Vol 8 (3) ◽  
pp. 034003
Author(s):  
Deborah S Barkauskas ◽  
Gregory Medley ◽  
Xiaowen Liang ◽  
Yousuf H Mohammed ◽  
Camilla A Thorling ◽  
...  

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