title: Encapsulation of a highly sensitive EPR active oxygen probe into sonochemically prepared microspheres.
abstract: High-power ultrasound (20 kHz) was used to encapsulate a solution of perchlorotriphenylmethyl triester (PTM-TE, a stable organic free radical) dissolved in hexamethyldisiloxane (HMDS) into a polymerized shell of bovine serum albumin (BSA). The size distribution of the microspheres was between 0.5 and 3 microm with a maximum at approximately 1.2 microm. The electron paramagnetic resonance spectrum of PTM-TE consists of a single, sharp line which is sensitive to the surrounding concentration of oxygen. It was found that the technique of encapsulating a solution of PTM-TE dissolved in HMDS into the BSA microspheres resulted in an overall loss of EPR signal intensity from the washed suspension of microspheres. However, the encapsulated PTM-TE/HMDS solution remained sensitive to the partial pressure of oxygen in the surrounding environment. The microspheres were found to be useful for determining the partial pressure of oxygen in the muscle and tumor tissue of mice.
authors: Center for Biomedical and EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.
authors: Joe Z
authors: JZ
authors: Sostaric
authors: Ramasamy P
authors: RP
authors: Pandian
authors: Anna
authors: A
authors: Bratasz
authors: Periannan
authors: P
authors: Kuppusamy
mesh_terms: D000818:Animals; D002722:Chlorobenzenes / Q000737:chemistry*; D004339:Drug Compounding; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D051379:Mice; D008809:Mice, Inbred C3H; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D018482:Muscle, Skeletal / Q000737:chemistry; D009369:Neoplasms / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D014018:Tissue Distribution; D014465:Ultrasonics
chemical_list: D002722:Chlorobenzenes; D012833:Siloxanes; D012710:Serum Albumin, Bovine; C015917:hexamethyldisiloxane; D009584:Nitrogen; D010100:Oxygen