Ultrasound characterization of oxygen contrast agents produced during the reaction of hydrogen peroxide with catalase-loaded nanoparticles

Christopher D. Malone, Yasan Yeh, Sadik Esener, Robert Mattrey, Kenneth Hoyt

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

We present a novel class of ultrasound (US) contrast agents, which enable de novo production of echogenic O2 microbubbles (MBs) in vivo in regions with elevated hydrogen peroxide (H2O2). The agent is a 200 nm silica shell nanoparticle loaded with catalase (catSHEL) that catalyzes H2O2 into water (H2O) and oxygen (O2). Importantly, this reactive process produces O2 MBs visible during US imaging. We have shown that this agent can detect elevated levels of H2O2 in kidneys with acute kidney injury (AKI). The purpose of this in vitro study is to further characterize the US properties of these O2 MBs. When exposed to US energy (mechanical index, MI = 0.07), a marked increase in the 2nd harmonic signal was recorded after the addition of H2O2 when the catSHELs were suspended in 25% plasma + phosphate buffered saline (PBS) versus PBS alone (13.1 vs. 1.7 dB). This harmonic gain abated at higher plasma concentrations (6.0 dB at 100% plasma) and higher (MI = 0.10) and lower (MI = 0.03) US transmit powers (8.8 and 5.7 dB, respectively). The harmonic signal also increased with increasing surfactant concentration. Again, the response was greatest at moderate acoustic power. O2 MBs produced in PBS alone were transient and relatively large, while those produced at increasing plasma and surfactant concentrations were smaller and longer lasting, suggesting that they are stabilized in plasma or surfactant. Overall, nonlinear US imaging may be suitable for the local visualization of O2 MBs produced in response to AKI.

Original languageEnglish (US)
Title of host publication2016 IEEE International Ultrasonics Symposium, IUS 2016
PublisherIEEE Computer Society
Volume2016-November
ISBN (Electronic)9781467398978
DOIs
StatePublished - Nov 1 2016
Event2016 IEEE International Ultrasonics Symposium, IUS 2016 - Tours, France
Duration: Sep 18 2016Sep 21 2016

Other

Other2016 IEEE International Ultrasonics Symposium, IUS 2016
CountryFrance
CityTours
Period9/18/169/21/16

Keywords

  • acute kidney injury
  • contrast agents
  • microbubbles
  • nanoparticles
  • ultrasound

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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    Malone, C. D., Yeh, Y., Esener, S., Mattrey, R., & Hoyt, K. (2016). Ultrasound characterization of oxygen contrast agents produced during the reaction of hydrogen peroxide with catalase-loaded nanoparticles. In 2016 IEEE International Ultrasonics Symposium, IUS 2016 (Vol. 2016-November). [7728513] IEEE Computer Society. https://doi.org/10.1109/ULTSYM.2016.7728513