Two-photon high-resolution measurement of partial pressure of oxygen in cerebral vasculature and tissue
Open Access
- 8 August 2010
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature Methods
- Vol. 7 (9), 755-759
- https://doi.org/10.1038/nmeth.1490
Abstract
Two-photon excitation of a phosphorescent nanoprobe that is quenched by molecular oxygen permits high-resolution measurements of oxygen in both the vasculature and tissue of rodent brain. Measurements of oxygen partial pressure (pO2) with high temporal and spatial resolution in three dimensions is crucial for understanding oxygen delivery and consumption in normal and diseased brain. Among existing pO2 measurement methods, phosphorescence quenching is optimally suited for the task. However, previous attempts to couple phosphorescence with two-photon laser scanning microscopy have faced substantial difficulties because of extremely low two-photon absorption cross-sections of conventional phosphorescent probes. Here we report to our knowledge the first practical in vivo two-photon high-resolution pO2 measurements in small rodents' cortical microvasculature and tissue, made possible by combining an optimized imaging system with a two-photon–enhanced phosphorescent nanoprobe. The method features a measurement depth of up to 250 μm, sub-second temporal resolution and requires low probe concentration. The properties of the probe allowed for direct high-resolution measurement of cortical extravascular (tissue) pO2, opening many possibilities for functional metabolic brain studies.This publication has 34 references indexed in Scilit:
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