Novel particulate spin probe for targeted determination of oxygen in cells and tissues

Ramasamy P. Pandian, Narasimham L. Parinandi, Govindasamy Ilangovan, Jay L. Zweier, Periannan Kuppusamy

Research output: Contribution to journalArticle


The synthesis and characterization of a new lithium octa-n-butoxy- substituted naphthalocyanine radical probe (LiNc-BuO) and its use in the determination of concentration of oxygen (oximetry) by electron paramagnetic resonance (EPR) spectroscopy are reported. The probe is synthesized as a needle-shaped microcrystalline particulate. The particulate shows a single-line EPR spectrum that is highly exchange-narrowed with a line-width of 210 mG. The EPR line-width is sensitive to molecular oxygen showing a linear relationship between the line-width and concentration of oxygen (pO2) with a sensitivity of 8.5 mG/mmHg. We studied a variety of physicochemical and biological properties of LiNc-BuO particulates to evaluate the suitability of the probe for in vivo oximetry. The probe is unaffected by biological oxidoreductants, stable in tissues for several months, and can be successfully internalized in cells. We used this probe to monitor changes in concentration of oxygen in the normal muscle and RIF-1 tumor tissue of mice as a function of tumor growth. The data showed a rapid decrease in the tumor pO2 with increase of tumor volume. Human arterial smooth muscle cells, upon internalization of the LiNc-BuO probe, showed a marked oxygen gradient across the cell membrane. In summary, the newly synthesized octa-n-butoxy derivative of lithium naphthalocyanine has unique properties that are useful for determining oxygen concentration in chemical and biological systems by EPR spectroscopy and also for magnetic tagging of cells.

Original languageEnglish (US)
Pages (from-to)1138-1148
Number of pages11
JournalFree Radical Biology and Medicine
Issue number9
StatePublished - Nov 1 2003
Externally publishedYes



  • Electron paramagnetic resonance
  • Free radical
  • Naphthalocyanine
  • Oximetry
  • Particulate
  • RIF-1 tumor
  • Spin probe

ASJC Scopus subject areas

  • Medicine(all)
  • Toxicology
  • Clinical Biochemistry

Cite this

Pandian, R. P., Parinandi, N. L., Ilangovan, G., Zweier, J. L., & Kuppusamy, P. (2003). Novel particulate spin probe for targeted determination of oxygen in cells and tissues. Free Radical Biology and Medicine, 35(9), 1138-1148.