LAUSR

Abstract Transdermal drug delivery offers several advantages over other conventional modalities for drug administration, such as injections and oral administrations. It can be activated by exogenous energy sources, including electric and magnetic fields, or by light and ultrasound (US). Ultrasound can induce the degradation and deformation of a polymeric matrix, thus promoting the release of entrapped drugs and the topical administration through the skin. Our aim is to create a wearable patch composed of an ultrasound-responsive polymeric system encapsulating specific drugs, which are released on demand by the application of ultrasound. In this work, we investigate the effect of ultrasound on square poly(lactic-co-glycolic acid) (PLGA) microparticles loaded with curcumin (CURC), called curcumin-microplates (CURC-μPLs), realized using a top-down fabrication process. Using Finite Element Method (FEM) simulations, we identified the resonant frequencies and the mode shape of the μPLs. Guided by this simulation, we applied ultrasound stimulus at frequency of 1 MHz, close to the first mechanical resonance frequency of the microplates, leading to a 200% increase in CURC release rate after 30 min of ultrasonic treatment. This approach can be generalized to any ultrasound-sensitive matrix filled with specific drugs and with piezoelectric compliant transducers embedded in the smart patch for generating ultrasonic waves.