An impedimetric biosensor for mucin 1 detection based on bilayer heteronanosheets and supercharged DNA three-way junctions

Bilayer heteronanosheets were prepared via self-assembly. • DNA three-way junctions were applied to achieve impedance signal amplification. • The biosensor shows high sensitivity and good reproducibility. Mucin 1 (MUC-1) is a promising biomarker of adenocarcinoma, thus sensitive and simple detection of MUC-1 is significantly important for the early diagnosis of this disease. Herein, an impedimetric biosensor for MUC-1 detection was developed, which was designed to achieve high sensitivity by introducing DNA three-way junctions (3WJ) on the sensor surface. For this purpose, hetero-bilayer nanosheets of reduced graphene oxide (rGO) and MnO 2 were applied to fabricate a stable and conductive sensor surface. PAMAM was modified to attach MUC-1 antibody on the surface. When MUC-1 was present, 3WJ can be introduced to the sensing interface via a DNA tail containing base sequence of MUC-1 aptamer. Because of the unique spatial configuration and negatively charged nature of 3WJ, diffusion of the redox probe [Fe(CN) 6 ] 3−/4– was greatly hindered. Consequently, impedance at the electrode/solution interface induced by MUC-1 was amplified, enabling a biosensor with high sensitivity. Using this biosensor, a detection limit as low as 4.3 pg·mL −1 was achieved. Furthermore, the biosensor also exhibited good specificity and reproducibility, demonstrating potential application in the diagnosis of adenocarcinoma and other related biological purpose. Download: Download high-res image (158KB) Download: Download full-size image