T2-Weighted and Ultra-short TE Molecular Magnetic Resonance Imaging for Gastric Cancer Diagnosis using Polymer-based Magnetic Nanoparticles

Abstract

Several recently developed technologies for molecular imaging have been applied to magnetic resonance (MR) imaging for cancer. In particular, various MR sequences with biocompatible polymer-based magnetic nanoparticles (pMNPs) have been applied for the MR imaging of cancer. However, there are several limitations to this approach, and passive contrast agents are not yet sufficiently targeted. This is a particular challenge for gastric cancer owing to the interference from stomach contents. Therefore, in this study we developed targeting contrast agent and assessed its feasibility for early gastric cancer diagnosis using a mouse model. Specifically, we synthesized pMNPs, which enable both T2-weighted (T2) and ultra-short TE (UTE) MR imaging using hyaluronic acid as the polymer, which binds to the receptor CD44, a recently identified biomarker of gastric cancer. Both MR sequences (T2, UTE) were analyzed with respect to imaging effects and targeting to the pMNPs. In vitro assessments showed no significant cytotoxicity of the pMNPs to MKN-45 and MKN-28 cells and confirmed the cellular uptake of the pMNPs. MR signal enhancement was identified after pMNPs injection to the mice, and the pMNPs gradually accumulated in the tumors. Based on the results, we suggest that pMNPs serve as useful probes for imaging stem-like cancer cells, and can further provide new possibilities by simultaneously confirming T1 and T2 MR imaging effects.