PH Dependence of MRI Contrast in Magnetic Nanoparticle Suspensions Demonstrates Inner-Sphere Relaxivity Contributions and Reveals the Mechanism of Dissolution.

ABSTRACT: Superparamagnetic iron oxide nanoparticles, MNPs, are under investigation as stimulus-responsive nanocarriers that can be tracked by magnetic resonance imaging. However, fundamental questions remain, including the effect of differing surface chemistries on MR image contrast efficacy (relaxivity), both initially and over time in the biological environment. The effects of pH and ligand type on the relaxivity of electrostatically and sterically stabilized spherical 8.8 nm superparamagnetic MNP suspensions are described. It is shown for the first time that across the pH ranges, within which the particles are fully dispersed, increasing acidity progressively reduces relaxivity for all ligand types. This effect is stronger for electrostatically (citrate or APTES) than for sterically stabilized (

SUBMITTER: MacMahon E 

PROVIDER: S-EPMC9933532 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature