Detection of magnetic nanoparticles in tissue using magneto-motive ultrasound

Abstract

The purpose of this study was to demonstrate the magneto-motive ultrasonic detection of superparamagnetic iron oxide (SPIO) nanoparticles as a marker of macrophage recruitment in tissue. The capability of ultrasound to detect SPIO nanoparticles (core diameter ∼20 nm) taken up by murine liver macrophages was investigated. Eight mice were sacrificed two days after the intravenous administration of four SPIO doses (1.5, 1.0, 0.5, and 0.1 mmol Fe/kg body weight). In the iron-laden livers, ultrasound Doppler measurements showed a frequency shift in response to an applied time-varying magnetic field. M-mode scan and colour power Doppler images of the iron-laden livers also demonstrated nanoparticle movement under focused magnetic field excitation. In the livers of two saline injected control mice, no movement was observed using any ultrasound imaging modes. The results of our experiments indicate that ultrasound imaging of magneto-motive excitation is a candidate imaging modality to identify tissue-based macrophages containing SPIO nanoparticles.

Depth-resolved analytical model and correction algorithm for photothermal optical coherence tomography

“…Ultrasound and photoacoustic [5] imaging have a penetration depth of up to 10 cm and have the advantage of being low cost, with equipment already available in the clinic. Ultrasound can image contrast agents such as microbubbles [6] and some nanoparticles [7] while photoacoustic imaging can image absorbers such as blood, melanin and a wide array of metallic nanoparticles. However, both ultrasound and photoacoustic imaging do not allow simultaneous multi-modality imaging since they use an ultrasound transducer, which complicates the coupling of multiple imaging techniques in one instrument and can also complicate the coupling of the instrument to the subject.…”

Chitosan-Coated Fe₃O₄ Magnetic Nanoparticles as Carrier of Cisplatin for Drug Delivery

“…Magnetic nanoparticles (MNPs) are currently used in various medical applications, such as drug delivery (Kohler et al, 2005;Zhang et al, 2005), magnetic resonance imaging (MRI), contrast agents (Kim et al, 2003), magneto-motive ultrasound (Oh et al, 2006), and optical imaging (Oh et al, 2007). Recently, drug-loaded Fe 3 O 4 NPs systems have been combined with hyperthermia treatments.…”

Dual-coil magnetomotive optical coherence tomography for contrast enhancement in liquids

“…In other words, the variation in magnetic particle displacements under a fixed magnetic field strength is highly correlated to the viscoelastic property of the surrounding medium [12,13]. Furthermore, this dual-coil approach is not only applicable in MM-OCT imaging, but also magnetomotive ultrasound imaging [19,20].…”