Bruce Drinkwater, University of Bristol, UK
Host: Peng Li
University of Bristol Department of Mechanical Engineering
Acoustical tweezers use acoustic radiation forces ad can be considered as non- contacting robotic hands capable of remotely moving and assembling matter. As these forces can be used to manipulate liquids and solids, animate and inanimate matter, so the applications are limitless. They are particularly effective acting on the micrometre level where they have been used to manipulate objects such as cells for a wide range of biomedical applications. However, the physical principles extend both below and above this size range. Acoustical tweezers are an enabling technology – not only can they improve and complement existing manipulation technologies, but they also enable completely new manipulation and assembly applications. This talk will review a number of acoustical tweezer devices and explore their applications. For example, patterning of microscale objects can be achieved in relatively simple devices, and these allow the rapid creation of uniform and large-scale micro-arrays. These arrays have been used to study coacervate-based protocell interactions and the response of protocells to chemical gradients. Similar devices can be used to selectively manipulate (i.e. sort or characterise) matter based on size, density or compressibility. Higher acoustic intensities can be used to deform soft matter to assess mechanical properties or provide mechanical stimulation. More complex devices can also be built that are capable of independent operations and can manipulate matter in a similar way to optical tweezers. Many of these devices can be manufactured and used with relatively low levels of experience or cost. Hence, the talk will describe the emergence of a versatile and accessible manipulation technology and discuss how it can contribute to new applications across the sciences.