Figure 1: Schematic of MNP-gold core-shell NPs and mechanism of background suppression using mmPA.
From: Multifunctional nanoparticles as coupled contrast agents
(a) Key steps involved in hybrid NP synthesis (figure not drawn to scale). Monodisperse hydrophobic MNPs coated with oleic acids are first solubilized using amphiphilic PL-PEG-COOH. PLH, which is capable of chelating metal ions, is then adsorbed onto PL-PEG-COOH by electrostatic interaction. On addition of gold ions and a reducing reagent, thin gold shells form on the polypeptide template rather than directly on core nanoparticles. The molecular structures of oleic acid, PL-PEG-COOH and PLH are shown below the reaction scheme. (b) Schematic of MNP-gold core-shell NPs' response to a magnetic field. The underlying red curve represents field strength. The coupled agents move as the magnetic field is turned on and off. (c) Schematic of contrast enhancement in mmPA imaging. mmPA imaging suppresses regions not susceptible to a controlled magnetic field while identifying regions with coupled agents responsive to a magnetic field.
