Bioinspired Adhesive Nanofiber Electronics with Three-dimensional Suction Cups for Efficient Transdermal Drug Delivery

Transdermal drug delivery (TDD) offers a non-invasive alternative to conventional administration but remains limited by the barrier function of the stratum corneum and the poor skin conformity of existing wearable devices. Here, we developed a skin-adaptive cellulose nanofiber (CNF)-based adhesive electronic platform integrating an octopus-inspired three-dimensional suction cup architecture with a conductive layer to enhance transdermal delivery.

The optimized imprinting process produced a high-resolution suction cup structure that maintained over 90% of its original geometry after absorbing hyaluronic acid (HA) solutions up to 15 wt%. Upon mild preloading, the bio-inspired architecture generated localized negative pressure, improving conformal skin contact and significantly increasing both normal and shear adhesion. Enhanced adhesion resulted in deeper HA penetration than hole-patterned and flat controls, reaching approximately 110 μm after 20 min of application.

To further improve delivery efficiency, a single-walled carbon nanotube conductive layer was integrated onto the opposite surface of the adhesive. The conductive interface generated physiologically relevant microcurrents (~50 μA), transiently reduced the electrical resistance of the stratum corneum, and promoted electro-assisted transport of HA. Human skin evaluation further demonstrated superior improvements in skin hydration, roughness, fine lines, and pore-related parameters compared with topical application and non-conductive controls.

These results demonstrate that the synergistic integration of bio-inspired suction adhesion and microcurrent stimulation provides an effective, fully non-invasive strategy for enhancing transdermal delivery, highlighting its potential for wearable therapeutics, cosmetic applications, and next-generation skin-interfaced drug delivery systems.