A wearable transdermal device for on-demand drug delivery

Microneedle (MN) patches have shown great potential in biomedical applications because of their minimal invasiveness and efficient drug delivery. However, challenges remain, such as restricted penetration depth, limited drug loading capacity, and the complexity of controlled release formulations. Here, we present a wearable transdermal device (WTD) system composed of a portable iontophoresis device with an electroresponsive hydrogel (electrogel) and polymeric MN patches. When activated by a programmed current of the WTD, the macroporous electrogel shrinks to control drug solution release and further transport into the skin via MN-generated microchannels, providing efficient, on-demand transdermal drug administration. In vivo experiments in a diabetic model demonstrated that the WTD system rescued mice from hyperglycemia or hypoglycemia by transdermally delivering insulin or glucagon, respectively. It enabled programmed delivery based on blood glucose levels to avoid multiple injections. Moreover, the WTD system could deliver high-dosing required chemo drug and effectively inhibited tumor growth in 4T1 tumor-bearing mice.