Highly ordered 3D electrochemical DNA biosensor based on dual orientation controlled rolling motor and graftable tetrahedron DNA.

Herein, a robust and highly ordered three-dimensional electrochemical DNA (3D E-DNA) biosensor was proposed, and its orientation was controlled from top down by poly adenine oligonucleotides (polyA-ODNs)-mediated rolling motor (PRM) and graftable tetrahedron DNA (GTD). The GTD with a grafting domain was immobilized on the electrode surface to construct a well-organized sensing interface and controlled the orientation and distribution of the whole system at the "bottom" of this biosensor. The polyA-ODNs regulated the direction and density of the leg DNA attached on PRM at the "top" of the biosensor. The motion was achieved through the target induced cyclic cleaving, which triggered the motor rolling rather than walk. Impressively, the duplex strand DNA (dsDNA) formed after grafting, as a girder, provided a stable support to the soft long single strand (ssDNA), which facilitated the formation of the catalytic center, elevated the efficiency of the rolling cleavage. Under the optimal conditions, the designed biosensor exhibited a lower limit of 0.17 nM and wide linear range from 0.5 nM to 1.5 μM for adenosine rapid detection. Unique dual orientation regulated characteristics of the system increased the probability hybridization enormously and improved the motion efficiency significantly, which offered new avenue of DNA nanomachines development in biosensor platform. • The 3D electrochemical DNA biosensor is highly ordered with the density and orientation are well controlled from top down. • The rolling motor is well-designed and triggered rolling by target induced cyclic cleaving. • A distinctive graftable tetrahedron DNA is proposed to constructed 3D sensing surface regulated the density of the whole system. • The graftable tetrahedron can be used to simultaneously construct different sensing strategies without re-synthesizing according to the target. • Poly adenine prompts the substrate DNA of rolling motor to adopt an upright conformation and program the direction and density of substrate DNA precisely. [ABSTRACT FROM AUTHOR]