Oxyphor R2 and G2: phosphors for measuring oxygen by oxygen-dependent quenching of phosphorescence

Anal Biochem. 2002 Nov 15;310(2):191-8. doi: 10.1016/s0003-2697(02)00384-6.


Oxygen-dependent quenching of phosphorescence is a useful and essentially noninvasive optical method for measuring oxygen in vivo and in vitro. Calibration of the phosphors is absolute, and once phosphors have been calibrated in one laboratory the same constants can be used by anyone else as long as the measurement is done under the same conditions. Two new phosphors, one based on Pd-meso-tetra-(4-carboxyphenyl)porphyrin and the other on Pd-meso-tetra-(4-carboxyphenyl)tetrabenzoporphyrin, are very well suited to in vivo oxygen measurements. Both phosphors are Generation 2 polyglutamic Pd-porphyrin-dendrimers, bearing 16 carboxylate groups on the outer layer. These phosphors are designated Oxyphor R2 and Oxyphor G2, respectively. Both are highly soluble in biological fluids such as blood plasma and their ability to penetrate biological membranes is very low. The maxima in the absorption spectra are at 415 and 524 nm for Oxyphor R2 and 440 and 632 nm for Oxyphor G2, while emissions are near 700 and 800 nm, respectively. The calibration constants of the phosphors are essentially independent of pH in the physiological range (6.4 to 7.8). In vivo application is demonstrated by using Oxyphor G2 to noninvasively determine the oxygen distribution in a subcutaneous tumor growing in rats.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biochemistry / instrumentation
  • Calibration
  • Glioma / blood supply
  • Glioma / metabolism
  • Hydrogen-Ion Concentration
  • Kinetics
  • Luminescent Measurements
  • Mesoporphyrins / chemistry*
  • Metalloporphyrins / chemistry*
  • Microcirculation
  • Optics and Photonics
  • Oxygen / analysis*
  • Oxygen / metabolism
  • Phosphorus / chemistry*
  • Pressure
  • Rats
  • Temperature
  • Tumor Cells, Cultured


  • Mesoporphyrins
  • Metalloporphyrins
  • oxyphor G2
  • oxyphor R2
  • Phosphorus
  • Oxygen