title: Fabrication and physical evaluation of a polymer-encapsulated paramagnetic probe for biomedical oximetry.
abstract: Lithium octa-n-butoxynaphthalocyanine (LiNc-BuO) is a promising probe for biological electron paramagnetic resonance (EPR) oximetry and is being developed for clinical use. However, clinical applicability of LiNc-BuO may be hindered by potential limitations associated with biocompatibility, biodegradation, and migration of individual crystals in tissue. To overcome these limitations, we have encapsulated LiNc-BuO crystals in polydimethyl siloxane (PDMS), an oxygen-permeable and bioinert polymer, to fabricate conveniently implantable and retrievable oxygen-sensing chips. Encapsulation was performed by a simple cast-molding process, giving appreciable control over size, shape, thickness and spin density of chips. The in vitro oxygen response of the chip was linear, reproducible, and not significantly different from that of unencapsulated crystals. Cast-molding of the structurally-flexible PDMS enabled the fabrication of chips with tailored spin densities, and ensured non-exposure of embedded LiNc-BuO, mitigating potential biocompatibility/toxicological concerns. Our results establish PDMS-encapsulated LiNc-BuO as a promising candidate for further biological evaluation and potential clinical application.
authors.affiliation: Center for Biomedical EPR Spectroscopy and Imaging, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Guruguhan
authors.initials: G
authors.lastname: Meenakshisundaram
authors.forename: Edward
authors.initials: E
authors.lastname: Eteshola
authors.forename: Ramasamy P
authors.initials: RP
authors.lastname: Pandian
authors.forename: Anna
authors.initials: A
authors.lastname: Bratasz
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Lee
authors.forename: Periannan
authors.initials: P
authors.lastname: Kuppusamy
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D008422:Materials Testing / Q000379:methods; D015335:Molecular Probes / Q000737:chemistry*; D010092:Oximetry / Q000379:methods*; D011166:Porphyrins / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*; D013113:Spin Labels
chemical_list: D001672:Biocompatible Materials; D015335:Molecular Probes; D011166:Porphyrins; D012828:Silicones; D013113:Spin Labels; C487013:lithium octa-n-butoxynaphthalocyanine; C078211:polymethylsiloxane