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

Abstract

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.

Cu2MoS4/Au Heterostructures with Enhanced Catalase‐Like Activity and Photoconversion Efficiency for Primary/Metastatic Tumors Eradication by Phototherapy‐Induced Immunotherapy

“…Due to the enhanced NIR absorption and prominent photothermal conversion performance, CMS/Au has the potential to be excellent photoacoustic imaging agent. [ 51,52 ] As shown in Figure A, the in vitro experiment demonstrated that the PA signal intensity of CMS/Au remarkably increased more obviously than that of CMS, and which strictly followed a concentration‐dependent linear relationship. To further evaluate the capability of CMS/Au for in vivo PA imaging, the U14 tumor‐bearing mice were injected with CMS/Au or CMS (100 µL, 15 mg kg −1 ) intravenously.…”

Nanoparticle contrast agents for X‐ray imaging applications

“…An exciting new research area in the field involves the development of activatable agents that can provide differential image contrast as a response to environmental triggers such as pH or enzyme expression. For example, ROS degradable AuNP-polyphosphazene nanoprobes could be used to detect the presence of inflammation and cancer using bimodal PAI and CT imaging (Bouché et al, 2019). A switchable polymer-AuNP complex, which we have described above, could track the delivery of therapeutic drugs to diseased neurons via CT imaging (L. Liu et al, 2019).…”

Internally Responsive Nanomaterials for Activatable Multimodal Imaging of Cancer

“…prepared an H 2 O 2 ‐activated CT and PA imaging. [ 52 ] In their design, gold nanoparticles (AuNPs) were loaded into hybrid polyphosphazene derived polymer nanogels formed through ionic interactions (PPB NPs). The sensitivity of this nanoprobe to ROS stemmed from the nanogel coating composed of poly[di(carboxylatophenoxy)phosphazene] (PCPP) and the arylboronate polyphosphazene derivative (PPB).…”