A highly sensitive electrochemical biosensor for mucin 1 based on gold nanorods conjugated with DNA three-way junction

Gold nanorods with different aspect ratios were synthesized by pH regulation. • A DNA three-way junction was employed for target recognition and AuNRs introduction. • A highly sensitive amperometric biosensor was developed for MUC-1 detection. Mucin 1 (MUC-1) is a valuable tumor-associated transmembrane glycoprotein. Electrochemical biosensor is a convenient tool for the quantitative detection of MUC-1 in biological samples. In this research, a new MUC-1 biosensor is developed based on gold nanorods conjugated with DNA three-way junction. The sandwiched biosensor is fabricated by covalent anchoring the anti-MUC-1 antibody on an electrode surface which is modified with the nanocomposite of silver nanoparticles and chitosan. In the presence of MUC-1, gold nanorods can be specifically introduced onto the sensor surface because of one aptamer tail of the DNA three-way junction, which is conjugated with gold nanorods via two thiol terminals. Then, the reductive current of H 2 O 2 monitored by amperometry increases drastically with the increase of MUC-1 concentration. Under the optimized conditions, the biosensor exhibited a linear response over the range of 100 fg·mL −1 to 1 μg·mL −1 , with a low detection limit of 54.3 fg·mL −1 . The biosensor showed good reproducibility, with an RSD of 4.7% for the response of five independently fabricated sensors. The detection recovery in spiked serum samples ranges from 87.1% to 110.0%, demonstrating the application potential of the proposed strategy for ultrasensitive electrochemical detection of MUC-1 in biological samples. Download: Download high-res image (193KB) Download: Download full-size image