Gliomas make up around 80% of malignant brain tumors and also affect the central nervous system, making it particularly important to achieve early and accurate diagnosis.

Traditional imaging methods (such as computed tomography (CT), magnetic resonance imaging (MRI), and photoacoustic imaging (PAI)) each have inherent disadvantages such as limited resolution, low imaging depth of penetration, and poor spatial resolution, and thus single-method imaging cannot provide enough information on the characteristics of different types of cancer. In order to resolve this problem, multi-modality imaging agents, which support several analytical methods at the same time, are sought.

Kun Wang, Zhongliang Wang, and Jie Tian and colleagues from the Beijing Key Laboratory of Molecular Imaging and from Xidian University in Xian, report in their recent article in Advanced Materials, the use of Au@MIL-88(Fe) nanoparticles that serve as triple-modality imaging agents, in CT, MRI, and PA imaging.

The particles, which consist of a metal-organic framework (MOF) shell layer on the surface of gold nanorods, exhibit low cytotoxicity and provide high contrast, thereby enabling substantial enhancement of imaging sensitivity, high depth of penetration, and spatial resolution for imaging of the cancers.

In vivo triple-modality imaging of U87 MG-orthotopic tumor-bearing mice, before and after i.v. injection with Au@MIL-88(Fe). a,b) CT images. c,d) T2-weighted MR e,f) PA imaging.

The core–shell nanocomposites simultaneously provide CT enhancement and improvement of the PAI performance due to the optical properties of the Au nanorod core, while the T2-weighted MRI performance is enhanced by the NMOF shells. In addition, the surface of the nanocomposites was modified with poly(ethylene glycol)-carboxyl acid (PEG-COOH) in order to protect from clotting, which shows the potential to allow decreased levels of exposure of stroke patients to CT imaging radiation.