“Living ink” 3D printing will allow construction of custom biochemical factories

The researchers, from the Swiss Federal Institute of Technology in Zurich (ETH Zurich), developed their ink using two bacteria as the active component: Pseudomonas putida, which can break down the very commonly-used but toxic chemical phenol; and Acetobacter xylinum, which secretes extremely pure nanocellulose, a promising material for dressing burns as it has analgesic and moisture-retaining properties. The ink, which has been dubbed “Flink” (functional living ink), is comprised of a viscous, biocompatible gel made from long-chain sugar molecules, silica and hyaluronic acid, and also contains the culture medium that feeds the bacteria.

The consistency of Flink is particularly crucial; it needs to be self-supporting, but must also allow the bacteria some freedom of movement. “The ink must be as viscous as toothpaste and have the consistency of Nivea hand cream,” explained Manuel Schaffner, who worked with research director Prof André Studart, head of the Laboratory for Complex Materials at ETH, which specialises in functional materials for 3D printing.