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Advanced Microfluidics & Diagnostics using Acoustic Holograms – Bio-Phononics

Final Report Summary - BIO-PHONONICS (Advanced Microfluidics & Diagnostics using Acoustic Holograms – Bio-Phononics)

The miniaturisation of medical technologies makes devices cheaper, reduces the costs of expensive reagents, enables smaller samples to be taken, painlessly and improves their performance. Methods to handle the small samples belong to a field known as “microfluidics” or Lab-on-a-Chip, involving developing technologies for the movement of fluids on or around microstructured surfaces, including channels. Flow is often driven by peristaltic pumps or in high electrical fields creating electrokinetic flows. In this project we created new techniques to enable pressure driven flow through the use of surface acoustic waves (SAWs) which propagate across the surface of the diagnostic device. To better control the nature of the acoustic field when using SAWs, we developed the concept of using periodic arrays known as phononic crystals within microfluidics. In doing so, we have enabled a new field exploring how liquids interact with these "acoustic holograms".

The way the structures work can be explained by analogy to traditional optical holograms, which change the field and create new visual patterns. Our acoustic holograms change the acoustic fields, shaping the ultrasonic field, and enabling us to make acoustic waveguides, mirrors and lenses. These new acoustic fields interact with fluids to create new microfludic flows.

We have been able to demonstrate how we can create interesting liquid manipulations, including four “real-world” examples, namely (i) sample preparation and identification of malarial parasites in whole blood; (ii) the measurement of the viscosity of blood, a key marker used in diagnosis to determine drug treatment following cardiovascular disease; (iii) new techniques for gene sequencing and finally (iv) new methods to create aerosols from liquids, which may have important applications in the delivery of medicines to the lungs.