Understanding Acoustic Cavitation Initiation by Porous Nanoparticles

Toward Nanoscale Agents for Ultrasound Imaging and Therapy

Adem Yildirim, Rajarshi Chattaraj, Nicholas T. Blum, Andrew P. Goodwin

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Ultrasound is widely applied in medical diagnosis and therapy due to its safety, high penetration depth, and low cost. In order to improve the contrast of sonographs and efficiency of the ultrasound therapy, echogenic gas bodies or droplets (with diameters from 200 nm to 10 μm) are often used, which are not very stable in the bloodstream and unable to penetrate into target tissues. Recently, it was demonstrated that nanobubbles stabilized by nanoparticles can nucleate ultrasound responsive microbubbles under reduced acoustic pressures, which is very promising for the development of nanoscale (<100 nm) ultrasound agents. However, there is still very little understanding about the effects of nanoparticle properties on the stabilization of nanobubbles and nucleation of acoustic cavitation by these nanobubbles. Here, a series of mesoporous silica nanoparticles with sizes around 100 nm but with different morphologies were synthesized to understand the effects of nanoparticle porosity, surface roughness, hydrophobicity, and hydrophilic surface modification on acoustic cavitation inception by porous nanoparticles. The chemical analyses of the nanoparticles showed that, while the nanoparticles were prepared using the same silica precursor (TEOS) and surfactant (CTAB), they revealed varying amounts of carbon impurities, hydroxyl content, and degrees of silica cross-linking. Carbon impurities or hydrophobic modification with methyl groups is found to be essential for nanobubble stabilization by mesoporous silica nanoparticles. The acoustic cavitation experiments in the presence of ethanol and/or bovine serum albumin (BSA) demonstrated that acoustic cavitation is predominantly nucleated by the nanobubbles stabilized at the nanoparticle surface not inside the mesopores. Finally, acoustic cavitation experiments with rough and smooth nanoparticles were suggested: a rough nanoparticle surface is needed to largely preserve surface nanobubbles after coating the surface with hydrophilic macromolecules, which is required for in vivo applications of nanoparticles.

Original languageEnglish (US)
Pages (from-to)5962-5972
Number of pages11
JournalChemistry of Materials
Volume28
Issue number16
DOIs
StatePublished - Aug 23 2016
Externally publishedYes

Fingerprint

Cavitation
Ultrasonics
Acoustics
Nanoparticles
Imaging techniques
Silicon Dioxide
Silica
Carbon
Stabilization
Impurities
Hydrophobicity
Bovine Serum Albumin
Macromolecules
Surface-Active Agents
Hydroxyl Radical
Surface treatment
Surface active agents
Ethanol
Nucleation
Porosity

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Cite this

Understanding Acoustic Cavitation Initiation by Porous Nanoparticles : Toward Nanoscale Agents for Ultrasound Imaging and Therapy. / Yildirim, Adem; Chattaraj, Rajarshi; Blum, Nicholas T.; Goodwin, Andrew P.

In: Chemistry of Materials, Vol. 28, No. 16, 23.08.2016, p. 5962-5972.

Research output: Contribution to journalArticle

Yildirim, Adem ; Chattaraj, Rajarshi ; Blum, Nicholas T. ; Goodwin, Andrew P. / Understanding Acoustic Cavitation Initiation by Porous Nanoparticles : Toward Nanoscale Agents for Ultrasound Imaging and Therapy. In: Chemistry of Materials. 2016 ; Vol. 28, No. 16. pp. 5962-5972.
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