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[Display omitted] • The system utilizes the specific affinity between aptamer and CEA. • The nanopore detect the DNA instead of directly detecting the translocation of CEA. • We realized the detection of CEA with a concentration as low as 0.1 nM. • The biosensor could be utilized in real serum sample analysis. In this paper, a novel detection technique for tumor marker carcinoembryonic antigen (CEA) has been developed by using a solid-state nanopore as a tool. The system utilizes the specific affinity between aptamer-modified magnetic Fe 3 O 4 and CEA, rather than directly detecting the translocation of CEA through the nanopore. The aptamer-modified magnetic Fe 3 O 4 was hybridized with tetrahedral DNA nanostructures (TDNs), and TDNs were released after CEA was added. We investigate the translocation behavior of individual TDNs through solid-state nanopores. The frequency of the blockage signals for TDNs is recorded for indirect detection of CEA. We realized the detection of CEA with a concentration as low as 0.1 nM and proved the specificity of the interaction between the aptamer. In addition, our designed nanopore sensing strategy can detect CEA in real samples. [ABSTRACT FROM AUTHOR]

Mucin 1(MUC1) is an effective marker of breast cancer, so it is of great significance to develop a simple, sensitive and highly selective MUC1 detection sensor. Herein, we constructed a label-free nanopore biosensor for rapid and highly sensitive detection of MUC1. The presence of MUC1 triggered the modification of the DNAzyme walking chain on the surface of Fe 3 O 4 nanoparticles and separation from the aptamer. In the presence of Zn2+, DNAzyme catalyzed hydrolytic cleavage of the hairpin substrate at the scissile rA. The DNAzyme was divided into two fragments and ssDNA was released. ssDNA products from the hairpin substrate can generate a current blocking signal during α-hemolysin nanopore testing. The frequency of signature events showed a linear response toward the concentration of MUC1 in the range of 0.01 nM–100 nM. The sensing system also exhibited high selectivity against other protein and can be used for the detection of real sample. [Display omitted] • MUC1-aptamer and DNAzyme hybridization reaction was used as sensing platform. • 3D DNA walker nanoprobe was used for both MUC1 recognition and signal amplification. • MUC1 was detected indirectly by cutting the DNA fragments. • The α-HL nanopore biosensor could be utilized in real sample analysis. [ABSTRACT FROM AUTHOR]