Targeted imaging of brain gliomas using multifunctional Fe₃O₄/MnO nanoparticles

Integrating T₁- and T₂-components of magnetic resonance (MR) imaging into a single particle has been demonstrated to be effective for improving the diagnostic accuracy. However, a T₁-T₂ dual modal MR contrast agent with glioma targeting ability remains unexplored. In this study, we prepared gourd-shaped Fe₃O₄/MnO hybrid NPs with a size of 25 nm through a thermal decomposition method. The water dispersibility was then obtained via a ligand exchange process with carboxylic acid-terminated silane. The sequential conjugation of chlorotoxin (CTX) and Cy5.5 on the carboxyl groups of attached silane endowed Fe₃O₄/MnO hybrid NPs with near-infrared fluorescence and glioma-targeting characteristics. The in vitro studies confirmed the targeting ability of Fe₃O₄/MnO-Cy5.5-CTX NPs toward C6 glioma cells. The in vivo T₁-T₂ dual modal MR imaging of glioma-bearing brain verified that the CTX conjugation led to a better contrast enhancement of the tumour tissue from the normal tissue both in T₁ and T₂ imaging, comparing to unconjugated NPs, which could enable more accurate diagnosis of gliomas.