Article

Biomedical Microdevices

, Volume 11, Issue 4, pp 817-826

Oxygen sensitivity and biocompatibility of an implantable paramagnetic probe for repeated measurements of tissue oxygenation

  • Guruguhan MeenakshisundaramAffiliated withDepartment of Internal Medicine, Ohio State UniversityDavis Heart and Lung Research Institute, Ohio State University
  • , Edward EtesholaAffiliated withDepartment of Biomedical Engineering, Ohio State UniversityDavis Heart and Lung Research Institute, Ohio State University
  • , Ramasamy P. PandianAffiliated withDepartment of Internal Medicine, Ohio State UniversityDavis Heart and Lung Research Institute, Ohio State University
  • , Anna BrataszAffiliated withDepartment of Internal Medicine, Ohio State UniversityDavis Heart and Lung Research Institute, Ohio State University
  • , Karuppaiyah SelvendiranAffiliated withDepartment of Internal Medicine, Ohio State UniversityDavis Heart and Lung Research Institute, Ohio State University
  • , Stephen C. LeeAffiliated withDepartment of Biomedical Engineering, Ohio State UniversityDavis Heart and Lung Research Institute, Ohio State University
  • , Murali C. KrishnaAffiliated withBiophysics Spectroscopy Section, Radiation Biology Branch, National Cancer Institute
  • , Harold M. SwartzAffiliated withEPR Center for Viable Systems, Dartmouth Medical School
  • , Periannan KuppusamyAffiliated withDepartment of Internal Medicine, Ohio State UniversityDavis Heart and Lung Research Institute, Ohio State University Email author 

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

The use of oxygen-sensing water-insoluble paramagnetic probes, such as lithium octa-n-butoxynaphthalocyanine (LiNc-BuO), enables repeated measurements of pO2 from the same location in tissue by electron paramagnetic resonance (EPR) spectroscopy. In order to facilitate direct in vivo application, and hence eventual clinical applicability, of LiNc-BuO, we encapsulated LiNc-BuO microcrystals in polydimethylsiloxane (PDMS), an oxygen-permeable and bioinert polymer, and developed an implantable chip. In vitro evaluation of the chip, performed under conditions of sterilization, high-energy irradiation, and exposure to cultured cells, revealed that it is biostable and biocompatible. Implantation of the chip in the gastrocnemius muscle tissue of mice showed that it is capable of repeated and real-time measurements of tissue oxygenation for an extended period. Functional evaluation using a murine tumor model established the suitability and applicability of the chip for monitoring tumor oxygenation. This study establishes PDMS-encapsulated LiNc-BuO as a promising choice of probe for clinical EPR oximetry.

Keywords

EPR oximetry Oxygen sensor Particulate probe Encapsulation Polymer coating Biocompatible EPR probe