Figure 1: Properties of magnetic iron oxide nanoparticles (MNPs).
From: Magnetic forces enable controlled drug delivery by disrupting endothelial cell-cell junctions
(a) A schematic diagram of MNP. Each MNP contains a magnetite nanocrystal and a phospholipid–PEG coating. The phospholipid layer provides anchoring sites for lipophilic fluorophores such as DiI or DiR for fluorescence tracing of MNP. (b,c) TEM images of 16 and 33 nm diameter magnetite nanocrystals. Inset in b shows phospholipid–PEG-coated MNPs negatively stained with phosphotungstic acid. The phospholipid–PEG coating of MNPs appears as the white corona surrounding the dark nanocrystals. Scale bar, 100 nm. (d) Magnetization curves of MNPs. (e) Absorption and emission spectra of 16 nm MNPs labelled with DiI (16 nm/DiI) and 33 nm MNPs labelled with DiR (33 nm/DiR), respectively. (f) Calculated magnetic force on individual MNPs as a function of the field strength. The gradient of the magnetic flux density was assumed to be 100 T m−1.
