Microalgae extracts show promise for 3D printing

Microalgae are said to be especially suitable as ‘biofactories’ to produce sustainable materials for 3D laser printing due to their high lipid and photoactive pigment content.

The team was led by Prof. Dr Eva Blasco, a scientist at the Institute for Molecular Systems Engineering and Advanced Materials (IMSEAM) at Heidelberg University, and their results are detailed in Advanced Materials.

The process involves focusing a laser beam from a two-photon 3D laser on a liquid, photoreactive resin (ink). At the focal point, the laser light activates photoinitiators and triggers a chemical reaction, causing local solidification of the ink.

To date, petrochemical-based polymers have often been used as inks for this 3D laser printing process, but microalgae show promise for this purpose due to their rapid growth rate, CO2-fixation, and biocompatibility.

“Despite their advantages, microalgae have hardly been considered as raw materials for light-based 3D printing,” Prof. Blasco said in a statement. For their experiments, the researchers selected Odontella aurita and Tetraselmis striata, which contain high levels of lipids in the form of triglycerides. The team extracted the triglycerides and functionalised them with acrylates to facilitate rapid curing under light irradiation.

The photoactive green pigments present in the microalgae proved to be suitable as photoinitiators. When exposed to light, they trigger the chemical reaction that solidifies the ink into a three-dimensional structure.

“In this way we avoid using potentially toxic additives like the photoinitiators used in conventional inks,” said first author Clara Vazquez-Martel, a doctoral candidate in Eva Blasco’s research team.

Using the new ink system, the researchers were able to produce different 3D microstructures with high precision, exhibiting complex features such as overhangs and cavities.

Using cell culture experiments, the researchers also investigated the biocompatibility of the microalgae-based inks. They prepared 3D microscaffolds on which cells were cultured for about 24 hours and observed a survival rate of almost 100 per cent.

“Our results open up new possibilities not only for more sustainable 3D printing with light, but also for life science applications – from 3D cell cultures to biocompatible implants,” said Prof. Blasco. The research was conducted within the Cluster of Excellence “3D Matter Made to Order”, a collaboration of Heidelberg University and the Karlsruhe Institute of Technology (KIT). This study involved researchers from the Spanish Bank of Algae at the University of Las Palmas de Gran Canaria.

The work was funded by the German Research Foundation, the Carl Zeiss Foundation, the Fonds der Chemischen Industrie, and the European Union.