Delivery of drugs or genes to individual cells is achieved on a nanoscale using electroporation techniques. In one method, a flow-through bioreactor having an inlet and an outlet connected by a flow chamber and a nanoporous membrane positioned in the flow chamber is used. Cells to be electroporated are flowed from the inlet to the outlet, a quantum of molecules of the at least one drug or gene in a fluid medium in the flow chamber. An electrical field applied in the flow chamber provides momentum to the molecules in the nanopores, resulting in delivery of the molecules into the plurality of cells.