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 Fe₃O₄ 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 H₂O₂ in the mildly acidic tumor microenvironment into hydroxyl radicals through the synergistic catalysis of Fe₃O₄ NPs and GOD. Then the MVs can be disintegrated by the radicals, and ultrasmall Fe₃O₄ NPs will be released from the MVs at the tumor site, enabling rapid clearance of the Fe₃O₄ NPs into urine and a direct colorimetric urinalysis of the tumor within 4 h. The magnetic nanoreporters had good biocompatibility, and the released Fe₃O₄ 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.