Oxygen Sensing Difluoroboron β-Diketonate Polylactide Materials with Tunable Dynamic Ranges for Wound Imaging

Christopher A. DeRosa, Scott A. Seaman, Alexander S. Mathew, Catherine M. Gorick, Ziyi Fan, James N. Demas, Shayn M. Peirce, Cassandra L. Fraser

Research output: Contribution to journalArticlepeer-review

101 Scopus citations

Abstract

Difluoroboron β-diketonate poly(lactic acid) materials exhibit both fluorescence (F) and oxygen sensitive room erature phosphorescence (RTP). Introduction of halide heavy atoms (Br and I) is an effective strategy to control the oxygen sensitivity in these materials. A series of naphthyl-phenyl (nbm) dye derivatives with hydrogen, bromide, and iodide substituents were prepared for comparison. As nanoparticles, the hydrogen derivative was hypersensitive to oxygen (0-0.3%), while the bromide analogue was suited for hypoxia detection (0-3% O2). The iodo derivative, BF2nbm(I)PLA, showed excellent F to RTP peak separation and a 0-100% oxygen sensitivity range, unprecedented for metal-free RTP emitting materials. Due to the dual emission and exceptionally long RTP lifetimes of these O2 sensing materials, a portable, cost-effective camera was used to quantify oxygen levels via lifetime and red/green/blue (RGB) ratiometry. The hypersensitive H dye was well matched to lifetime detection; simultaneous lifetime and ratiometric imaging was possible for the bromide analogue, whereas the iodide material, with intense RTP emission and a shorter lifetime, was suited for RGB ratiometry. To demonstrate the prospects of this camera/material design combination for bioimaging, iodide boron dye-PLA nanoparticles were applied to a murine wound model to detect oxygen levels. Surprisingly, wound oxygen imaging was achieved without covering (i.e., without isolating from ambient conditions, air). Additionally, wound healing was monitored via wound size reduction and associated oxygen recovery, from hypoxic to normoxic. These single-component materials provide a simple tunable platform for biological oxygen sensing that can be deployed to spatially resolve oxygen in a variety of environments.

Original languageEnglish (US)
Pages (from-to)1366-1373
Number of pages8
JournalACS Sensors
Volume1
Issue number11
DOIs
StatePublished - Nov 23 2016
Externally publishedYes

Bibliographical note

Funding Information:
We thank the National Institutes of Health (R01 CA167250 (CLF); T32 GM008715 (SAS); P30 CA44579), the UVA Cancer Center, The Hartwell Foundation (SMP), the Wallace H. Coulter Foundation (SMP), and UVA Department of Chemistry (JND) for support for this work. Dr. Patrick S. Cottler at UVA Department of Plastic Surgery is acknowledged for helpful discussions and Anthony Bruce, for managing the mouse colony. We also thank Alan Reyes, Mehrad Mehr, Nguyen Nguyen, Emily Keeley and Charlotte Keeley for related preliminary studies. We thank the National Institutes of Health (R01 CA167250 (CLF); T32 GM008715 (SAS); P30 CA44579).

Publisher Copyright:
© 2017 American Chemical Society.

Keywords

  • RGB camera imaging
  • difluoroboron β-diketonate complexes
  • fluorescence
  • poly(lactic acid)
  • ratiometric oxygen sensing
  • room erature phosphorescence
  • wound healing

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