M. J. VOGEL & P. H. STEEN (2010)  Proceedings of the National Academy of Sciences of the United States of America 107, 3377-3381.

Summary
Drawing inspiration from the adhesion abilities of a leaf beetle found in nature, we have engineered a switchable adhesion device. The device combines two concepts: The surface tension force from a large number of small liquid contacts can be significant (capillarity-based adhesion) and these contacts can be quickly made or broken with electronic control (switchable). The device grabs or releases a substrate in a fraction of a second via a low-voltage pulse (9-Volt battery) that drives electroosmotic flow.
Adhesion strengths presently demonstrated are modest, but scaling arguments show that strengths will increases as feature size is decreased.  For example, devices that are one square inch and the thickness of a credit card could have a holding capacity of 15 pounds.

From figures: Device concept and assembly

Fig 1A: Switchable wet adhesion cycle concept. Full caption here.

Fig 2A: Switchable adhesion device schematic. Full caption here.

Videos: Device in action