Fig. 1: Schematic illustration of the smartphone-powered IMAP drug delivery system and its mechanism.

a Schematic illustration of a smartphone-powered transdermal drug delivery system. It mainly consists of an IMAP (the expanded view is shown on the left), an iontophoresis-driven circuit (the structure diagram is shown on the right), and a smartphone. The IMAP is composed of a medical tape, an electrode with conductive film, an anti-seepage gasket, an MA and a reservoir loaded with drug solution. The portable circuit can stabilize the input voltage and output a constant current for the iontophoresis of drugs under the power supply of the smartphone. b Schematic representation of the drug delivery mechanism of the IMAP: “Penetration, Diffusion and Iontophoresis”. Once the compression on the IMAP is removed, the MA will retract into the reservoir, and microholes are created on the skin. Then, a mild electric current is conducted between a pair of electrodes (IMAP and Ag/AgCl electrode) to drive the charged therapeutic molecules through microholes.