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Updated: Feb 1, 2026

Synthesis and Calibration of Phosphorescent Nanoprobes for Oxygen Imaging in Biological Systems
Published on: March 3, 2010
Two-photon phosphorescence lifetime microscopy of retinal capillary plexus oxygenation in mice
İkbal Şencan1, Tatiana V Esipova2, Mohammad A Yaseen1
1Massachusetts General Hospital, Harvard Medical School, Athinuola A. Martinos Center for Biomedical, United States.
Abstract:
Impaired oxygen delivery and/or consumption in the retinal tissue underlies the pathophysiology of many retinal diseases. However, the essential tools for measuring oxygen concentration in retinal capillaries and studying oxygen transport to retinal tissue are still lacking. We show that two-photon phosphorescence lifetime microscopy can be used to map absolute partial pressures of oxygen (pO2) in the retinal capillary plexus. Measurements were performed at various retinal depths in anesthetized mice under systemic normoxic and hyperoxic conditions. We used a newly developed two-photon phosphorescent oxygen probe, based on a two-photon absorbing platinum tetraphthalimidoporphyrin, and commercially available optics without correction for optical aberrations of the eye. The transverse and axial distances within the tissue volume were calibrated using a model of the eye's optical system. We believe this is the first demonstration of in vivo depth-resolved imaging of pO2 in retinal capillaries. Application of this method has the potential to advance our understanding of oxygen delivery on the microvascular scale and help elucidate mechanisms underlying various retinal diseases.
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