Acoustically-Driven Manipulation of Micro-Particles in Fluid on Piezoelectric Resonant Mass Sensors

Description

Advancements in micro/nano fabrication technology has enabled the realization of precision instruments capable of measuring single-cell biomass. This has be shown to be a powerful tool for a wide range of disciplines. Areas of application and impact have included research into personalized cancer drug treatment and ecological studies of nutrient flow in oceans. However, existing tools to measure the mass of µ-particles and cells in fluids are rather constrained in the re-configurability and difficult to scale with low throughput. More commonly, the performance of resonant devices acting as the mass sensor are rather poor when immersed in a fluid. There is also a lack of dexterity in manipulating samples over the sensor based on existing approaches. There is a need to apply manipulation techniques with a high level of dexterity to mass sensing resonators. The approach should be less costly than existing instruments and require less power density for the technique to be biocompatible.This proposal aims to apply recent advancements in acoustic manipulation techniques to one of our piezoelectric resonators (the BL-mode disk resonator) that leads the existing state-of-art in performance. The proposed approach has several advantages over existing methods:Lower cost and reduced fabrication complexityGreater flexibility for re-configuration by using a two-chip approachIntegration of different fluidic operations on-chip selected by a simple change in the excitation frequencyScalable to implement arrays for high throughputPower densities less than a millionth required of optical tweezersBy leveraging our recent advances on state-of-art AlN-on-Si piezoelectric resonators operating in fluids, we will scale down the device size to realize a resonant mass sensing platform with a resolution of 10fg as part of the 1stresearch objective. This level of resolution is sufficient to measure the effect of a µ-particle on the resonator frequency as it is moved across the device. The 2ndobjective aims to demonstrate movement and trapping of µ-particles over the sensor using acoustic waves with a high level of control in two dimensions. The 3rdobjective pushes the technique further to demonstrate µ-centrifugation by shaping the acoustic waves using phononic lattices integrated with the sensor. The effect of µ-centrifugation may be visualised by a spinning µ-particle in a fluid droplet on the sensor. At the end of this project, we aim to show the capability totranslate, trap, spin and weighµ-particles electrically on-chip. This will be a powerful tool for multiple science and engineering disciplines.