Iontophoresis

[1][2] Molecules are transported across the stratum corneum by electrophoresis and electroosmosis and the electric field can also increase the permeability of the skin.

By microelectrophoretic techniques, including microiontophoresis, neurotransmitters and other chemical agents can be artificially administered very near living and naturally functioning neurons, the activity of which can be simultaneously recorded.

A small electric current is applied to an iontophoretic chamber placed on the skin, containing a charged active agent and its solvent vehicle.

[10][11] Iontophoresis of acetylcholine is used in research as a way to test the health of the endothelium by stimulating endothelium-dependent generation of nitric oxide and subsequent microvascular vasodilation.

The negative charge of the skin at buffered pH causes it to be permselective to cations such as sodium and potassium ions, allowing iontophoresis which causes electroosmosis, solvent flow towards the anode.