Researchers from the University of California San Diego have introduced an innovative material designed to purify water in an eco-friendly manner. This “engineered living material” is a 3D-printed structure made from a seaweed-based polymer and genetically modified bacteria. These bacteria produce enzymes that convert organic pollutants into harmless molecules. Additionally, the bacteria can self-destruct when exposed to theophylline, a molecule found in tea and chocolate, ensuring they don’t persist in the environment after their task is complete.

The study, published in Nature Communications, highlights the unique combination of a polymer and a biological system, creating a living material that can react to stimuli differently than typical synthetic materials. The research was a joint effort between engineers, materials scientists, and biologists at the UC San Diego Materials Research Science and Engineering Center (MRSEC).

The living material was created using alginate, a seaweed-derived polymer, combined with cyanobacteria, a type of photosynthetic bacteria. The mixture was 3D-printed into a grid-like structure, which was found to be the most effective shape for keeping the bacteria alive and maximizing decontamination due to its high surface area to volume ratio.

For the study, the cyanobacteria were genetically modified to produce a decontaminating enzyme called laccase, known to neutralize various organic pollutants. The material was tested on the dye-based pollutant indigo carmine, a blue dye used in the textile industry, and successfully decolorized a water solution containing the dye.

To address concerns about genetically modified bacteria remaining in the environment, the bacteria were engineered to self-destruct in the presence of theophylline. Future research aims to make the bacteria self-destruct without adding chemicals, responding to naturally occurring environmental stimuli.

The study underscores the potential of interdisciplinary research, combining materials and biological sciences, to develop groundbreaking solutions for pressing environmental challenges.