Silica-coated super paramagnetic iron oxide nanoparticles (SPION) as biocompatible contrast agent in biomedical photoacoustics

Abstract

In this study, we report for the first time the use of silica-coated superparamagnetic iron oxide nanoparticles (SPION) as contrast agents in biomedical photoacoustic imaging. Using frequency-domain photoacoustic correlation (the photoacoustic radar), we investigated the effects of nanoparticle size, concentration and biological media (e.g. serum, sheep blood) on the photoacoustic response in turbid media. Maximum detection depth and the minimum measurable SPION concentration were determined experimentally. The nanoparticle-induced optical contrast ex vivo in dense muscular tissues (avian pectus and murine quadricept) was evaluated and the strong potential of silica-coated SPION as a possible photoacoustic contrast agents was demonstrated.

In vitro toxicity of Fe_mO_n, Fe_mO_n-SiO₂ composite, and SiO₂-Fe_mO_n core-shell magnetic nanoparticles

“…The most commonly used IONP coating materials are silica, 30 polyethylene glycol, 31 dextran and its derivatives, 32 chitosan, 33 and carbon. 34 Very recently, silica-coated IONPs have been tested as contrast agents for biomedical photoacoustic imaging 35 and T1 MRI. 18 Most of the available evidence suggests that IONP coating results in reduced toxicity; there are, however, recent studies that have questioned the protective role of the coating.…”

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

“…[345] Also, the transparent matrix of silica allows the efficient passage of excitation and emission light for better imaging diagnosis. [346] Modification of magnetite nanoparticles was firstly performed by Philipse et al [347] through a sol-gel approach. They reported a good dispersion of coated magnetite nanoparticles in aqueous suspensions due to intrinsic hydrophilic property of silica.…”

Biomedical photoacoustics: fundamentals, instrumentation and perspectives on nanomedicine

“…64 As an exclusion, superparamagnetic iron oxide nanoparticles (SPIONs) have been approved by the US Food and Drug Administration and applied as nanoprobes for molecular PAI. 65 SPIONs coated with silica were also employed in photoacoustic tomography (PAT), which showed great sensitivity with a minimum detectable concentration of ∼0.17 and ∼0.23 mg/mL at depths of 5 and 10 mm inside the intralipids, respectively. 66 The maximum penetration depth and optical stability of silicacoated SPIONs were studied as well.…”