Operation of Self-Sensitive Cantilever in Liquid for Multiprobe Manipulation

We describe a novel and simple operation method of using a self-sensitive cantilever of an atomic force microscopy (AFM) system in liquid. As for operation of the cantilever in liquid, Al lines of an integrated piezoresistor patterned on the cantilever are easily damaged by electrochemical corrosion. To realize safe operation without the damage, an additional electrode was inserted into the liquid. By applying DC voltage and controlling the potential of the electrode, the Al lines of the piezoresistor circuit on the cantilever could be protected from the electrochemical corrosion. By using this method, AFM imaging of collagen fibrils was demonstrated in physiological saline. Furthermore, the technique allowed us to realize a multiprobe AFM system with a simple configuration. Two cantilever probes were successfully operated like a knife and fork for the manipulation of collagen fibers in liquid.