Directed Acoustic Assembly in 3D

TL;DR

This paper introduces a novel contactless acoustic method for rapid, one-step assembly of 3D structures from various materials, including biological cells, enabling advancements in biofabrication and tissue engineering.

Contribution

It demonstrates a new holographic acoustic technique that assembles matter into 3D shapes without scaffolds or opposing waves, improving speed and biocompatibility.

Findings

Successfully assembled 3D structures with solid particles, hydrogels, and cells.

The method is compatible with standard labware and allows fixation via gelation.

Supports positive acoustic contrast materials without opposing waves.

Abstract

The creation of whole 3D objects in one shot is an ultimate goal for rapid prototyping, most notably biofabrication, where conventional methods are typically slow and apply mechanical or chemical stress on biological cells. Here, we demonstrate one-step assembly of matter to form compact 3D shapes using acoustic forces, which is enabled by the superposition of multiple holographic fields. The technique is contactless and shown to work with solid microparticles, hydrogel beads and biological cells inside standard labware. The structures can be fixed via gelation of the surrounding medium. In contrast to previous work, this approach handles matter with positive acoustic contrast and does not require opposing waves, supporting surfaces or scaffolds. We envision promising applications in tissue engineering and additive manufacturing.