Long-Term Evaluation of Inserted Nanocomposite Hydrogel-Based Phosphorescent Oxygen Biosensors: Evolution of Local Tissue Oxygen Levels and Foreign Body Response

Abstract

Phosphorescence-based oxygen-sensing hydrogels are a promising platform technology for an upcoming generation of insertable biosensors that are smaller, softer, and potentially more biocompatible than earlier designs. However, much remains unknown about their long-term performance and biocompatibility in vivo. In this paper, we design and evaluate a range of hydrogel sensors that contain oxygen-sensitive phosphors stabilized by micro- and nanocarrier systems. These devices demonstrated consistently good performance and biocompatibility in young adult rats for over three months. This study thoroughly establishes the biocompatibility and long-term suitability of phosphorescence lifetime sensors in vivo, providing the groundwork for expansion of this platform technology into a family of small, unobtrusive biosensors for a range of clinically relevant metabolites.