US Patent 7771451 Method and apparatus for the deployment of vaso-occlusive coils

A vaso-occlusive delivery device includes an elongate delivery member which may take the form of a core wire. An actuating member is disposed at or adjacent to the distal end of the delivery member. The actuating member includes an electroactive polymer that can be selectively biased to an expanded or non-expanded state by application of direct current of different polarities. A vaso-occlusive device such as a coil may be detachably secured to the delivery device by expanding the actuating member within a proximal end of the coil to form an interference or friction fit using a first direct current polarity. The coil may be disengaged from the delivery member by application of direct current of a second, opposite polarity.