Described is a device and method for administration of molecules to tissue in vivo for various medical applications, the device comprising a single hypodermic injection needle and at least two spaced elongate electrodes which provide for the ability, when the needle is inserted into tissue, such as skin or muscle, to pulse tissue with a non-uniform electric field sufficient to cause reversible poration of cells lying along or in close proximity to the track made by the needle upon its insertion into said tissue.