Microalgae like the diatom Odontella aurita and the green alga Tetraselmis striata serve as excellent “biofactories” for creating eco-friendly materials for 3D laser printing thanks to their rich lipid and photoactive pigment content. A global research team spearheaded by Prof. Dr. Eva Blasco from the Institute for Molecular Systems Engineering and Advanced Materials (IMSEAM) at Heidelberg University has achieved the groundbreaking feat of producing inks for printing intricate biocompatible 3D microstructures, utilizing raw materials derived from these microalgae. These microalgae-based substances might be utilized in the future for fabricating implants or scaffolds for 3D cell cultures.
Among various additive manufacturing methods, two-photon 3D laser printing stands out for its advantages in fabricating at micro and nanoscale levels. Its exceptional resolution allows it to be employed across a multitude of fields like optics and photonics, microfluidics, and biomedicine. The process works by directing a laser beam at a liquid photoreactive resin, known as “ink.” At the focused point, the laser activates specific molecules called photoinitiators which instigate a chemical reaction that leads to the localized solidification of the ink.
Historically, inks for this highly accurate 3D laser printing technique have primarily relied on petrochemical-based polymers. These materials pose issues such as fossil fuel depletion, greenhouse gas emissions, and potential toxicity, as noted by Prof. Blasco. Microalgae represent a promising alternative as “biofactories” for sustainable 3D printing materials, given their fast growth, CO2 fixation during growth, and biocompatibility. “Despite their benefits, microalgae have seldom been explored as raw materials for light-based 3D printing,” highlights Prof. Blasco, whose research straddles areas of macromolecular chemistry, materials science, and 3D nanofabrication.
The research team has successfully extracted biocompatible materials suitable for high-resolution 3D laser printing from microalgae for the first time. For their study, they focused on the two species, the diatom Odontella aurita and the green alga Tetraselmis striata, both of which are rich in triglycerides. The team extracted triglycerides and modified them with acrylates to enable fast curing when exposed to light. The green pigments from the microalgae were found to be effective photoinitiators; upon light exposure, they initiate the chemical process that solidifies the ink into a complex three-dimensional form. “This method eliminates the need for potentially harmful additives, such as traditional photoinitiators,” points out Clara Vazquez-Martel, the lead author and a PhD student in Prof. Blasco’s team at IMSEAM.
With the newly developed ink system, the researchers created various highly detailed 3D microstructures, showcasing intricate designs including overhanging features and cavities. They further examined the biocompatibility of the microalgae-based inks through cell culture experiments, successfully cultivating cells on 3D microscaffolds for approximately 24 hours, observing nearly a 100 percent survival rate. “These findings pave the way for more sustainable light-based 3D printing and open new avenues for life science applications—ranging from 3D cell cultures to biocompatible implants,” remarks Prof. Blasco.
This research is part of the Excellence Cluster “3D Matter Made to Order,” a collaborative effort between Heidelberg University and the Karlsruhe Institute of Technology (KIT). The study involved researchers from Heidelberg, KIT, and the Spanish Bank of Algae at the University of Las Palmas de Gran Canaria (ULPGC, Spain). Funding for this project was provided by organizations including the German Research Foundation, the Carl Zeiss Foundation, the Fonds der Chemischen Industrie, and the European Union as part of the European Territorial Cooperation Program. The findings have been published in the journal “Advanced Materials.”
