The surface-confined DNA sequence is able to change its configuration between rigid tetramolecular G-quadruplex and flexible single-stranded structures. The large conformational change enables the probes to perform an inchworm like extending-shrinking motion, which is reflected by the fluctuation in current intensity. 表面限定的DNA序列能够在刚性四元G-四股螺旋与弹性单链结构间相互转换。这种较大的形态改变使得DNA序列能够象尺蠖一样做伸―缩运动,产生了电流变化。