Digital acoustofluidics enables contactless and programmable liquid handling

Abstract

For decades, scientists have pursued the goal of performing automated reactions in a compact fluid processor with minimal human intervention. Most advanced fluidic handling technologies (e.g., microfluidic chips and micro-well plates) lack fluid rewritability, and the associated benefits of multi-path routing and re-programmability, due to surface-adsorption-induced contamination on contacting structures. This limits their processing speed and the complexity of reaction test matrices. We present a contactless droplet transport and processing technique called digital acoustofluidics which dynamically manipulates droplets with volumes from 1 nL to 100 µL along any planar axis via acoustic-streaming-induced hydrodynamic traps, all in a contamination-free (lower than 10−10% diffusion into the fluorinated carrier oil layer) and biocompatible (99.2% cell viability) manner. Hence, digital acoustofluidics can execute reactions on overlapping, non-contaminated, fluidic paths and can scale to perform massive interaction matrices within a single device.

Wave number–spiral acoustic tweezers for dynamic and reconfigurable manipulation of particles and cells

“…In particular, surface acoustic wave (SAW) tweezers have additional advantages in terms of precision, versatility, and suitability for point-of-care applications (17,18). SAW tweezers are capable of manipulating micro/nano-objects for a wide range of applications, including patterning particles and cells (26,27), controlling cell-cell interactions (28), cell printing (16,29), particle/cell separation and sorting (30,31), manipulating organisms (10), generating and translating droplets (32)(33)(34)(35), and isolating extracellular vesicles (36).…”

Programmable Acoustic Metasurfaces

“…Acoustic beams, such as focused, tweezer‐like, and nonparaxial beams, are of interest for a wide range of applications including medical acoustic imaging, nondestructive evaluation, acoustic tweezers, energy harvesting, and wireless energy transfer . Although acoustic beams can be generated using conventional passive metasurfaces, those metasurfaces with fixed configurations lack maneuverability in tuning and reshaping the acoustic beams, once they are designed and fabricated.…”

Dispersion tuning and route reconfiguration of acoustic waves in valley topological phononic crystals

“…For miniaturized devices, the response time would be further reduced. These research directions are important steps toward fast, miniaturized designs that can be integrated with precision electro-acoustic systems [62][63][64] to develop advanced acoustic tweezers for high-resolution dynamic manipulation of nano-to micro-objects.…”