Ultrasound-propelled nanoporous gold wire for efficient drug loading and release.

Ultrasound (US)-powered nanowire motors based on nanoporous gold segment are developed for increasing the drug loading capacity. The new highly porous nanomotors are characterized with a tunable pore size, high surface area, and high capacity for the drug payload. These nanowire motors are prepared by template membrane deposition of a silver-gold alloy segment followed by dealloying the silver component. The drug doxorubicin (DOX) is loaded within the nanopores via electrostatic interactions with an anionic polymeric coating. The nanoporous gold structure also facilitates the near-infrared (NIR) light controlled release of the drug through photothermal effects. Ultrasound-driven transport of the loaded drug toward cancer cells followed by NIR-light triggered release is illustrated. The incorporation of the nanoporous gold segment leads to a nearly 20-fold increase in the active surface area compared to common gold nanowire motors. It is envisioned that such US-powered nanomotors could provide a new approach to rapidly and efficiently deliver large therapeutic payloads in a target-specific manner.