Tunable Acoustic Tweezers for Droplet Carrier Transportation and Pretreatment of Loaded Micro-Analytes

We report for the first time the fusion of two functions for droplet carrier transportation and pretreatment of loaded micro-analytes by a tunable surface acoustic wave (SAW) device. A narrow acoustic wave beam could be excited by frequency tuning to sweep the droplets located at different positions, which can quickly move the different volumes of droplets and offers an asymmetric acoustic field for droplet centrifugation in a staged or synchronized process upon requirement. An optimized superhydrophobic contact angle of the droplet will promote the effective leakage of the Rayleigh wave on the open interface and greatly reduce the viscous resistance.