The manipulator includes a support and at least one member affixed to and extending away from the support. The member has at least two differentially activatable areas of conductivity. The members are configured to establish a first electromagnetic field in vivo between selected areas of conductivity sufficient to manipulate a molecule relative to a target tissue and to establish a second, typically higher, electromagnetic field sufficient to cause transient permeability of a cell membrane within the target tissue. Restraining means are also described for restricting movement of the members with relation to each other. One method of using the device is for enhancing the delivery of a molecule into a tissue site; another is for poration of the tissue alone or in combination with the migration. The target tissue may include a tumor, organ, or wound site.