Single Particle ICP-MS Characterization of Magnetoliposomes: Toward a Measurement of Number Distribution of Encapsulated Magnetic Nanoparticles

Abstract

Magnetoliposomes (MLs) are very pertinent candidates for biomedical applications. They can be used as drug delivery vectors, but also as magnetic resonance imaging (MRI) contrast agents. Their characterization in terms of size, and size distribution by dynamic light scattering (DLS), surface charge by electrophoretic light scattering, and morphology by (cryo)-transmission electron microscopy (TEM) is well documented in the literature. However, no study of the distribution of number of encapsulated magnetic nanoparticles (NPs) per ML has been described so far despite its importance in the design of efficient MLs for the targeted application. The work presented herein reveals that this information could be obtained thanks to a relatively innovative technique, i.e. single particle inductively coupled plasma-mass spectrometry (spICP-MS). This has required the development of an orderly calculation methodology and a mathematical treatment of raw data detailed herein, and validated on four different concentrations of MLs. The results about this number of encapsulated magnetic NPs per ML show a satisfactory agreement between all the concentrations, confirming the interest of this technique for such a characterization.