This study describes the use of two-photon excitation phosphorescence lifetime measurements for quantitative oxygen determination in vivo. Doubling the excitation wavelength of Pd-porphyrin from visible light to the infrared allows for deeper tissue penetration and a more precise and confined selection of the excitation volume due to the nonlinear two-photon effect. By using a focused laser bea...

While the phosphorescence of aromatic chromophores in solution is normally quenched through diffusion of dissolved oxygen and other solvent-mediated processes, the phosphorescence of some proteins in solution is observed at room temperature. The tryptophan phosphorescence arises from residues which are hindered from interaction with oxygen by the folding of the polypeptide chains. Measurements ...

We report an extension to the technique of molecular tagging thermometry which allows for adjustable temperature sensitivity. The temperature dependence of laser-induced phosphorescence of the water-soluble phosphorescent triplex (1-BrNp MbCD ROH) is used to conduct temperature measurements in aqueous flows. It is shown that the temperature sensitivity of phosphorescence intensity can be adjust...

Measurement of the room temperature Trp triplet state lifetime in proteins by time-resolved phosphorescence can provide valuable information on the structure and dynamics of proteins in solution. Our time-resolved absorption measurements on the long-lived states resulting from electronic excitation of the chromophore demonstrate the presence of more complex behavior than revealed by time-resolv...

A fluorene derivative having both bromo and formyl groups exhibited bright phosphorescence emission in common organic solvents at room temperature. The absolute phosphorescence quantum yield reached 5.9% in chloroform at 298 K. When the fluorene derivative was incorporated into a poly(methyl methacrylate) film, the phosphorescence emission was similarly observed even under air at room temperatu...

Phosphorescence spectroscopy has been used to probe the microenvironments of the tryptophan residues of the cyclic antibiotic decapeptides tyrocidine B (which contains a single tryptophan residue) and tyrocidine C (which contains 2 tryptophan residues). Both peptides exhibited two distinct, overlapping tryptophan phosphorescence emission spectra under appropriate solvent conditions. The two emi...

Mik, Egbert G., Ton G. van Leeuwen, Nicolaas J. Raat, and Can Ince. Quantitative determination of localized tissue oxygen concentration in vivo by two-photon excitation phosphorescence lifetime measurements. J Appl Physiol 97: 1962–1969, 2004. First published July 9, 2004; doi:10.1152/japplphysiol.01399.2003.—This study describes the use of two-photon excitation phosphorescence lifetime measure...

Phosphorescence signaling provides a valuable alternative to conventional bioimaging based on fluorescence. The benefits of using phosphorescent molecules include improved sensitivity and capabilities for effective elimination of background signals by time-gated acquisition. Cyclometalated Ir(III) complexes are promising candidates for facilitating phosphorescent bioimaging because they provide...

Oxygen-dependent quenching of phosphorescence has been used to image the distribution of oxygen pressure in small tumors and surrounding tissue. Suspensions of cultured 9L cells or small pieces of solid tumors from 9L cells were injected into the surface of the muscle of the hindquarter of rats, and the tumors were grown until they were 0.2-1.0 cm in diameter. The phosphorescent probe for oxyge...