A portable multicolor aptasensor for MUC1 detection based on enzyme-mediated cascade reaction

Mucin 1 (MUC1) is an important tumor biomarker, and the determination of MUC1 is of great significance in clinical diagnostics, prognosis assessment and therapy monitoring. Developing point-of-care testing method of MUC1 is necessary in resource-limited settings. Herein, a visual multicolor aptasensor for MUC1 detection was designed based on an alkaline phosphatase (ALP)-triggered cascade reaction. In the presence of MUC1, ALP-decorated complementary DNA and MUC1 aptamer on magnetic beads were dissociated due to the recognition between MUC1 and aptamer. With the assistance of a magnet, ALP-decorated complementary DNA was separated and collected to catalyze the hydrolysis of l -ascorbic acid-2-phosphate generating l -ascorbic acid, which etched the manganese dioxide nanosheets to mediate the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine sulfate, resulting in different products with distinct visible multicolor. The naked eye detection of MUC1 was realized and the detection limit was estimated to be 0.18 U mL −1 by using the colorimetric method. This proposed aptasensor possesses the merit of vivid multicolor change, and provides a new way for MUC1 detection by naked eyes.