Macrophage Membrane-Camouflaged Chitosan Nanogels Loaded with Ultrasmall Iron Oxide Nanoparticles Enable Magnetic Resonance Imaging of Orthotopic Glioma

Development of advanced biocompatible nanoprobes to cross the blood–brain barrier (BBB) for accurate magnetic resonance (MR) imaging of gliomas is a quite challenging task. We develop here the macrophage cell membranes (MCM)-coated chitosan (CS) nanogels (NGs) loaded with ultrasmall iron oxide nanoparticles (USIO NPs) to cross BBB for T1-weighted MR imaging of glioma. First, CS NGs were created using an emulsion method, covalently conjugated with USIO NPs prepared via a solvothermal method, and coated with MCM to possess an average size of 146.3 nm. The generated USIO-CS@MCM NGs display desired cytocompatibility, BBB-crossing ability, and glioma-targeting property. Notably, the r1 relaxivity of USIO-CS@MCM NGs (3.06 mM–1·s–1) is 20 times larger than that of USIO NPs (0.15 mM–1·s–1). Meanwhile, compared to the USIO-CS NGs, the USIO-CS@MCM NGs offer superior BBB penetration capacity with the assistance of the MCM coating, thus enabling effective T1-weighted MR imaging of orthotopic glioma. The developed USIO-CS@MCM NGs represent a promising nanoprobe for accurate MR imaging of glioma or other brain diseases.