Single-stranded DNA regulated peroxidase mimetic activity of MCOF@AuNPs for colorimetric detection of carcinoembryonic antigen

Schematic diagram of colorimetric detection of CEA. • The peroxidase-like activity of MCOF@AuNPs functionalized by CEA-specific aptamer has been developed, with its peroxidase-like activity being tunable by ssDNA. • A colorimetric strategy was established to detection of CEA by the enzyme activity enhancement effect by ploy G-terminated CEA-specific aptamer. • The whole detection procedure was achieved within 35 min, and the LOD is 0.1 ng/mL. • The development of app based on the RGB model to assay colorimetric results. Rapid, accurate, simple and portable monitoring of carcinoembryonic antigen (CEA) in serum is important for assessing the occurrence, development, and prognosis of cancer. In this work, we developed a colorimetric method based on the peroxidase-like activity of MCOF@AuNPs functionalized by complementary sequences of CEA-specific aptamer (MCOF@AuNPs-apt*) enhancing by G-terminated CEA-specific aptamer (G-apt). The enhancement of catalytic activity depends on the increase affinity of MCOF@AuNPs-apt*-G-apt to the TMB via promoting electron transfer. Based on this strategy, we successfully detected CEA at 0.1 ng/mL with high accuracy and anti-interference ability. Importantly, combined with the smartphone app based on the smartphone app RGB color model, the results can be visualized directly without expensive equipment, which meets the demand for point of care testing of CEA. This study also explored the enhancement of catalytic activity of nanozyme by ssDNA and the application potential in aptamer biosensor.