A novel ratiometric electrochemical aptasensor for highly sensitive detection of carcinoembryonic antigen.

A novel ratiometric electrochemical aptasensor was proposed for carcinoembryonic antigen (CEA) detection based on exonuclease III (Exo III)-assisted recycling and rolling circle amplification (RCA) strategies. A thiolated ferrocene-labeled hairpin probe 2 (Fc-HP2) was fixed on the gold nanoparticles (AuNPs)-modified gold electrode (AuE) surface through Au-S bonds. The presence of CEA led to the release of trigger, which hybridized with the 3'-protruding of hairpin probe 1 (HP1) and triggered the Exo III cleavage reaction, accompanied by the releasing of trigger and generation of new DNA fragment which was used for the successive hybridization with Fc-HP2.

Ratiometric electrochemical aptasensor for the sensitive detection of carcinoembryonic antigen based on a hairpin DNA probe and exonuclease I-assisted target recycling.

A novel ratiometric electrochemical aptasensor was constructed for the detection of carcinoembryonic antigen (CEA) based on a hairpin DNA (hpDNA) probe and exonuclease Ⅰ (Exo Ⅰ)-assisted target recycling amplification strategy. A thiolated methylene blue (MB)-labeled hpDNA as the internal control element was fixed on the surface of the gold nanoparticles (AuNPs)-modified gold electrode (AuE) through Au-S bonds. A ferrocene (Fc)-modified aptamer DNA (Fc-Apt) was partially hybridized with hpDNA to form a Fc-Apt/hpDNA duplex.