Effects of Nanoparticle Size on Cellular Uptake and Liver MRI with Polyvinylpyrrolidone-Coated Iron Oxide Nanoparticles

TLDR

The study systematically investigated how nanoparticle size affects MRI of normal liver and hepatic lesions in vivo. The authors synthesized size‑tunable, biocompatible PVP‑coated iron oxide nanoparticles via a simple one‑pot pyrolysis method. They found that larger nanoparticles (up to 120 nm) have higher T2 relaxivity, increased cellular uptake, and greater liver accumulation, with 100‑nm PVP‑IO‑37 nanoparticles delivering the strongest contrast for hepatic lesions, demonstrating that size and surface properties critically determine pharmacokinetics and imaging performance.

Abstract

The effect of nanoparticle size (30−120 nm) on magnetic resonance imaging (MRI) of hepatic lesions in vivo has been systematically examined using polyvinylpyrrolidone (PVP)-coated iron oxide nanoparticles (PVP-IOs). Such biocompatible PVP-IOs with different sizes were synthesized by a simple one-pot pyrolysis method. These PVP-IOs exhibited good crystallinity and high T2 relaxivities, and the relaxivity increased with the size of the magnetic nanoparticles. It was found that cellular uptake changed with both size and surface physiochemical properties, and that PVP-IO-37 with a core size of 37 nm and hydrodynamic particle size of 100 nm exhibited higher cellular uptake rate and greater distribution than other PVP-IOs and Feridex. We systematically investigated the effect of nanoparticle size on MRI of normal liver and hepatic lesions in vivo. The physical and chemical properties of the nanoparticles influenced their pharmacokinetic behavior, which ultimately determined their ability to accumulate in the liver. The contrast enhancement of PVP-IOs within the liver was highly dependent on the overall size of the nanoparticles, and the 100 nm PVP-IO-37 nanoparticles exhibited the greatest enhancement. These results will have implications in designing engineered nanoparticles that are optimized as MR contrast agents or for use in therapeutics.