Renal Clearable Magnetic Nanoreporter for Colorimetric Urinalysis of Tumor.

The convenience and availability are of great significance for the early screening of cancer. Herein, a magnetic nanoreporter with renal clearable capability and activatable catalytic activity was developed for colorimetric urinalysis of tumors. The magnetic nanoreporters were prepared by loading 3.2 nm FeO nanoparticles (NPs) and glucose oxidase (GOD) into macrophage cell-derived microvesicles (MVs) through electroporation, and these compositions serve as renal clearable catalytic reporters, synergistic catalysts, and targeted delivery carriers, respectively. The magnetic nanoreporters can convert the HO in the mildly acidic tumor microenvironment into hydroxyl radicals through the synergistic catalysis of FeO NPs and GOD. Then the MVs can be disintegrated by the radicals, and ultrasmall FeO NPs will be released from the MVs at the tumor site, enabling rapid clearance of the FeO NPs into urine and a direct colorimetric urinalysis of the tumor within 4 h. The magnetic nanoreporters had good biocompatibility, and the released FeO NPs were rapidly excreted from the body, avoiding the potential toxicity. We envision that the magnetic nanoreporters can be used for convenient and rapid cancer screening.