Sustainable soft systems thanks to multi-material 3D printing with organic inks

The production of complex soft systems using 3D printing has made considerable progress in recent years. In a recent study, a new method was presented that makes biodegradable materials usable for soft robotics and medical applications. This involves an innovative approach that combines gelatine-based hydrogels with a new type of support material.

The hydrogels used consist of gelatine, glucose, water and glycerine. They are thermoreversible, durable and easy to process. This material is supplemented by a biodegradable support material made of protein and sugars, which provides stability through foam formation. This material can be cold extruded and enables the printing of structures with overhangs of up to 60°. After the printing process, the support material is selectively removed by an ammonium sulphate solution without damaging the main structure, allowing complex internal geometries such as channels or cavities to be created.

This technology has been used to print vascular networks with channels as small as 700 micrometers in diameter, which could be used in tissue culture or microfluidics, for example. In addition, a soft sensor was developed that precisely detects mechanical strain. Another example is a vacuum-based actuator that enables fast movements with minimal energy input. This actuator also proved to be resistant to mechanical damage and could be repaired by heating.

The study provides detailed insights into the development and optimization of the materials as well as the technical challenges involved in manufacturing complex geometries. It is published in Advanced Materials.