Activatable Hybrid Polyphosphazene-AuNP Nanoprobe for ROS Detection by Bimodal PA/CT Imaging

ACS Appl Mater Interfaces. 2019 Aug 14;11(32):28648-28656. doi: 10.1021/acsami.9b08386. Epub 2019 Aug 1.


Overproduction of reactive oxygen species (ROS) is often related to inflammation or cancer and can cause tissue damage. Probes that have been previously reported to image ROS typically rely on imaging techniques that have low depth penetration in tissue, thus limiting their use to superficial disease sites. We report herein a novel formulation of hybrid nanogels loaded with gold nanoparticles (AuNP) to produce contrast for computed tomography (CT) and photoacoustics (PA), both being deep-tissue imaging techniques. The polyphosphazene polymer has been designed to selectively degrade upon ROS exposure, which triggers a switch-off of the PA signal by AuNP disassembly. This ROS-triggered degradation of the nanoprobes leads to a significant decrease in the PA contrast, thus allowing ratiometric ROS imaging by comparing the PA to CT signal. Furthermore, ROS imaging using these nanoprobes was applied to an in vitro model of inflammation, that is, LPS-stimulated macrophages, where ROS-triggered disassembly of the nanoprobe was confirmed via reduction of the PA signal. In summary, these hybrid nanoprobes are a novel responsive imaging agent that have the potential to image ROS overproduction by comparing PA to CT contrast.

Keywords: ROS; computed tomography; gold nanoparticles; photoacoustic; polyphosphazene.

MeSH terms

  • Animals
  • Contrast Media* / chemistry
  • Contrast Media* / pharmacology
  • Gold* / chemistry
  • Gold* / pharmacology
  • Hep G2 Cells
  • Humans
  • Metal Nanoparticles / chemistry*
  • Mice
  • Multimodal Imaging*
  • Organophosphorus Compounds* / chemistry
  • Organophosphorus Compounds* / pharmacology
  • Photoacoustic Techniques*
  • Polymers* / chemistry
  • Polymers* / pharmacology
  • RAW 264.7 Cells
  • Reactive Oxygen Species / analysis*
  • Tomography, X-Ray Computed*


  • Contrast Media
  • Organophosphorus Compounds
  • Polymers
  • Reactive Oxygen Species
  • poly(phosphazene)
  • Gold