title: Method measuring oxygen tension and transport within subcutaneous devices.
abstract: Cellular therapies hold promise to replace the implantation of whole organs in the treatment of disease. For most cell types, in vivo viability depends on oxygen delivery to avoid the toxic effects of hypoxia. A promising approach is the in situ vascularization of implantable devices which can mediate hypoxia and improve both the lifetime and utility of implanted cells and tissues. Although mathematical models and bulk measurements of oxygenation in surrounding tissue have been used to estimate oxygenation within devices, such estimates are insufficient in determining if supplied oxygen is sufficient for the entire thickness of the implanted cells and tissues. We have developed a technique in which oxygen-sensitive microparticles (OSMs) are incorporated into the volume of subcutaneously implantable devices. Oxygen partial pressure within these devices can be measured directly in vivo by an optical probe placed on the skin surface. As validation, OSMs have been incorporated into alginate beads, commonly used as immunoisolation devices to encapsulate pancreatic islet cells. Alginate beads were implanted into the subcutaneous space of Sprague–Dawley rats. Oxygen transport through beads was characterized from dynamic OSM signals in response to changes in inhaled oxygen. Changes in oxygen dynamics over days demonstrate the utility of our technology.
authors.affiliation: University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California 92617, United StatesbUniversity of California Irvine, Department of Biomedical Engineering, Irvine, California 92617, United States.
authors.forename: John
authors.initials: J
authors.lastname: Weidling
authors.affiliation: University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California 92617, United StatesbUniversity of California Irvine, Department of Biomedical Engineering, Irvine, California 92617, United States.
authors.forename: Sara
authors.initials: S
authors.lastname: Sameni
authors.affiliation: University of California Irvine, Department of Biomedical Engineering, Irvine, California 92617, United StatescUniversity of California Irvine, Department of Surgery, Orange, California 92868, United States.
authors.forename: Jonathan R T
authors.initials: JR
authors.lastname: Lakey
authors.affiliation: University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California 92617, United StatesbUniversity of California Irvine, Department of Biomedical Engineering, Irvine, California 92617, United StatescUniversity of California Ir.
authors.forename: Elliot
authors.initials: E
authors.lastname: Botvinick
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D002478:Cells, Cultured; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007515:Islets of Langerhans / Q000378:metabolism*; D016381:Islets of Langerhans Transplantation / Q000295:instrumentation*; D010092:Oximetry / Q000295:instrumentation* / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013552:Swine
chemical_list: D010100:Oxygen