In vivo measurement of the tissue oxygenation by time-resolved luminescence spectroscopy of protoporphyrin IX: strategies to minimize artefacts associated with photoproducts

Detection of tissue and cell oxygenation is of high importance in fundamental biological and in many medical applications, particularly for monitoring dysfunction in the early stages of cancer. Measurements of the luminescence lifetimes of molecular probes offer a very promising and non-invasive approach to estimate tissue and cell oxygenation in vivo and in vitro. We optimized the evaluation of oxygen detection in vivo by [Ru(Phen)3]2+ in the chicken embryo chorioallantoic membrane model. Its luminescence lifetimes measured in the CAM were analyzed through hierarchical clustering. The detection of the tissue oxygenation at the oxidative stress conditions is still challenging. We applied simultaneous time-resolved recording of the mitochondrial probe MitoTrackerTM OrangeCMTMRos fluorescence and [Ru(Phen)3]2+ phosphorescence imaging in the intact cell without affecting the sensitivities of these molecular probes. [Ru(Phen)3]2+ was demonstrated to be suitable for in vitro detection of oxygen under various stress factors that mimic oxidative stress: other molecular sensors, H2O2, and curcumin-mediated photodynamic therapy in glioma cancer cells. Low phototoxicities of the molecular probes were finally observed. Our study offers a high potential for the application and generalization of tissue oxygenation as an innovative approach based on the similarities between interdependent biological influences. It is particularly suitable for therapeutic approaches targeting metabolic alterations as well as oxygen, glucose, or lipid deprivation.

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In vivo measurement of time-resolved autofluorescence at the human fundus

Journal of Biomedical Optics ◽

10.1117/1.1806833 ◽

2004 ◽

Vol 9 (6) ◽

pp. 1214 ◽

Cited By ~ 81

Author(s):

Dietrich Schweitzer ◽

Martin Hammer ◽

Frank Schweitzer ◽

Roswitha Anders ◽

Torsten Doebbecke ◽

...

Keyword(s):

Time Resolved ◽

In Vivo Measurement

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Time-resolved multi-channel optical system for assessment of brain oxygenation and perfusion by monitoring of diffuse reflectance and fluorescence

Opto-Electronics Review ◽

10.2478/s11772-014-0178-y ◽

2014 ◽

Vol 22 (1) ◽

Cited By ~ 26

Author(s):

D. Milej ◽

A. Gerega ◽

M. Kacprzak ◽

P. Sawosz ◽

W. Weigl ◽

...

Keyword(s):

Near Infrared ◽

Tissue Oxygenation ◽

Brain Perfusion ◽

Clinical Tool ◽

Brain Tissue Oxygenation ◽

Signal Processing Algorithm ◽

Time Resolved ◽

Fluorescence Measurements ◽

Instrument Construction

AbstractTime-resolved near-infrared spectroscopy is an optical technique which can be applied in tissue oxygenation assessment. In the last decade this method is extensively tested as a potential clinical tool for noninvasive human brain function monitoring and imaging. In the present paper we show construction of an instrument which allows for: (i) estimation of changes in brain tissue oxygenation using two-wavelength spectroscopy approach and (ii) brain perfusion assessment with the use of single-wavelength reflectometry or fluorescence measurements combined with ICG-bolus tracking. A signal processing algorithm based on statistical moments of measured distributions of times of flight of photons is implemented. This data analysis method allows for separation of signals originating from extra- and intracerebral tissue compartments. In this paper we present compact and easily reconfigurable system which can be applied in different types of time-resolved experiments: two-wavelength measurements at 687 and 832 nm, single wavelength reflectance measurements at 760 nm (which is at maximum of ICG absorption spectrum) or fluorescence measurements with excitation at 760 nm. Details of the instrument construction and results of its technical tests are shown. Furthermore, results of in-vivo measurements obtained for various modes of operation of the system are presented.

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