Development and evaluation of biocompatible inks for the local measurement of oxygen using in vivo EPR.
In vivo EPR oximetry is a powerful minimally invasive method that allows the measurement of oxygen in tissues through the use of a paramagnetic probe. In the present study, we investigated new strategies for preparing biocompatible inks containing carbon black particles (Printex U), which could be used as oxygen sensors. The carbon black particles were dispersed in solutions of biocompatible polymers of carboxy methyl cellulose (CMC), hydroxypropyl methyl cellulose (HPMC) or polyvinyl pyrrolidone (PVP). A total of 12 polymers with different molecular weights were tested. A physico-chemical characterization of the inks was carried out to assess the sedimentation of the particles, the rheological behavior of these inks, and the relative diffusion of the inks. The preparations with CMC and PVP had the highest viscosity and stability. The presence of the polymers did not modify the calibration curves (EPR linewidth as a function of the pO2) of the carbon black. In vivo, the oxygen sensors were stable for at least one month in muscles as the EPR linewidth remained fully sensitive to induced ischemia or carbogen challenge. The calibration curve was not modified after this period of implantation. A first study of biocompatibility was carried out in vitro (hemolysis and cytotoxicity assay) and in vivo (histological examination). No sign of toxicity was observed using these inks. These preparations are good candidates for future in vivo studies including clinical trials.
Charlier
Nicolas
N
Laboratory of Medicinal Chemistry and Radiopharmacy, Biomedical Magnetic Resonance Unit, Avenue Mounier 73.40, University Catholique de Louvain, B-1200 Brussels, Belgium.
Beghein
Nelson
N
Gallez
Bernard
B
D000818:Animals; D002244:Carbon; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000009:adverse effects / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D066298:In Vitro Techniques; D007281:Ink; D008297:Male; D008422:Materials Testing; D051379:Mice; D015335:Molecular Probes / Q000009:adverse effects / Q000737:chemistry; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D010100:Oxygen / Q000032:analysis / Q000378:metabolism*; D014018:Tissue Distribution
D020099:Coated Materials, Biocompatible; D015335:Molecular Probes; D002244:Carbon; D010100:Oxygen