Abstract

Ultrasound – A New Tool for Biofabrication

Kai Melde, Group Leader, Heidelberg University

Biofabrication includes methods that print bioinks or directly assemble biological components (e. g. cells, microgels or spheroids) with the goal of creating functional tissues. Most of these methods require direct mechanical access (e. g. extrusion printing or aspiration-based pick & place) and work serially (point-by-point or layer-by-layer), which scales poorly to volumetric shapes and applies undue stress on biological cells. Over the last decade, ultrasound emerged as a tool for contactless manipulation of matter, including microparticles and biological cells. Its ease-of-use and favorable operating parameters led to a wide adoption especially in the microfluidics community (e. g. for cell sorting). However, the effects of ultrasound can act over much larger length scales, provided that there is sufficient control over the sound field. In this talk, I will present how ultrasound combined with holographic beamforming enables us to create very complex sound fields, which can direct the parallel assembly of matter to arbitrary shapes in 3D. Our technique is compatible with standard labware (such as sample tubes, culture inserts or cuvettes) and shown to work with solid microparticles, hydrogel beads and mammalian cells. As such, ultrasound promises to become a new tool for biofabrication, enabling the formation of cell aggregates without contact.