An artificial cilia-based array system for sound frequency decoding and resonance-responsive drug release

Hair cells in the human ear contain cilia of varying lengths that sense varied acoustic signals. Here, inspired by this, we report an artificial cilia-based sound-decoding device capable of directly recognizing and responding to sound frequencies without relying on electricity and algorithms. We create 3D-printed micrometre-sized (40-200 μm) artificial cilia-based arrays with varying length-to-diameter ratios (30-100) that can sense and decode sound frequency signals (100-6,000 Hz), including piano music and human voices, on the basis of acoustic resonance. The artificial cilia can also vibrate accordingly in water to initiate subsequent tasks such as controlling drug release profiles of two distinct therapeutics (insulin and glucagon) in an acoustic-frequency-responsive manner to treat type 1 diabetic mice. This cochlear cilia-inspired device holds potential for broad applications such as recognizing complicated physiological sounds and performing various tasks in personalized voice interactions.