title: Polymer coating of paramagnetic particulates for in vivo oxygen-sensing applications.
abstract: Crystalline lithium phthalocyanine (LiPc) can be used to sense oxygen. To enhance biocompatibility/stability of LiPc, we encapsulated LiPc in Teflon AF (TAF), cellulose acetate (CA), and polyvinyl acetate (PVAc) (TAF, previously used to encapsulate LiPc, was a comparator). We identified water-miscible solvents that don't dissolve LiPc crystals, but are solvents for the polymers, and encapsulated crystals by solvent evaporation. Oxygen sensitivity of films was characterized in vitro and in vivo. Encapsulation did not change LiPc oximetry properties in vitro at anoxic conditions or varying partial pressures of oxygen (pO2). EPR linewidth of encapsulated particles was linear with pO2, responding to pO2 changes quickly and reproducibly for dynamic measurements. Encapsulated LiPc was unaffected by biological oxidoreductants, stable in vivo for four weeks. Oximetry, stability and biocompatibility properties of LiPc films were comparable, but both CA and PVAc films are cheaper, and easier to fabricate and handle than TAF films, making them superior.
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Eteshola
authors.forename: Ramasamy P
authors.initials: RP
authors.lastname: Pandian
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Lee
authors.forename: Periannan
authors.initials: P
authors.lastname: Kuppusamy
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D007211:Indoles / Q000032:analysis* / Q000737:chemistry*; D008280:Magnetics; D009942:Organometallic Compounds / Q000032:analysis* / Q000737:chemistry*; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000032:analysis* / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D020099:Coated Materials, Biocompatible; D007211:Indoles; D009942:Organometallic Compounds; D011108:Polymers; C081756:lithium phthalocyanine; D010100:Oxygen