3D-Printed Sculptures That Glow — Made from Living Algae

Pyrocystis lunula — an organism known for brief flashes of blue light — can sometimes produce literal sparks in breaking waves on the shore. Researchers at the University of Colorado Boulder recreated that effect in the lab and managed to keep the glow going.
Julia Bracci, who ran the experiments in a darkened lab, said the team first tried to make the algae glow by applying mechanical pressure to mimic wave force. “We tried slowly compressing them,” she recalls. “But they didn’t respond much.” Other teams have had some success that way, but mechanical stimulation is hard to control.
So the team tried a different approach. Earlier studies had shown that acid lowers the pH inside the light-producing part of the cell and that drop triggers light emission. Bracci added a mildly acidic solution to a glass vial containing the algae — and instead of seeing a laptop reflection she saw a living, glittering surface: the algae inside the vial lit up.
In a paper in Science Advances, the authors report that the team was able to sustain the glow for up to 25 minutes straight. They then encapsulated the algae in a hydrogel — a jelly-like, water-based material — and 3D-printed several shapes with that material. All of the figures glowed a bright turquoise-blue.

The glow comes from the enzyme luciferase and its light-producing substrate luciferin — both names come from the Latin lucifer, meaning “light-bearer.” “They’re pretty self-sustaining if they have access to seawater,” said Professor Wil Srubar of the same university.
Srubar said this kind of “living light” could form the basis for glow bracelets or small bioluminescent lanterns at festivals. In theory, the algae could also be built into biosensors that light up in response to environmental toxins.
“Translating this from controlled lab conditions to the real world will be difficult — but it’s a very interesting first step,” said Chris Howe of the University of Cambridge, who was not involved in the study.
Howe added that for small light devices currently powered by single-use batteries, swapping to bioluminescence in some cases could significantly reduce the waste created when batteries are discarded.
At the same time, Professor Emeritus Anthony Campbell of Cardiff University noted that acid can induce bioluminescence in some algae species. He doubts the organisms would survive long in a solution with a pH of 4 — about the same acidity as a tomato. “They don’t like that; it stresses them,” Campbell said.
One question that remains unanswered is why Pyrocystis lunula and similar species evolved to glow in the first place. The flashes might serve a defensive role — scaring off potential predators. “I think that’s a fairly plausible explanation — but we don’t know for sure,” Howe concluded.
This article is based on reporting by The Guardian