The technique allows the researchers to guide the growth of bacterial colonies, using moulds with superhydrophobic (extremely water repellent) surfaces. These moulds are produced by simply embedding hydrophobic particles in silicone.
Unlike the fibrous objects made using conventional 3D-printing methods, the technique allows for fibres – with a diameter 1,000 times thinner than a human hair – to be aligned in any orientation, across layers, and in various gradients of thickness and topology by controlling wetting, incubation time, and nutrient availability. This opens up a world of possible applications in fields such as tissue regeneration; the physical characteristics of these objects are crucial for supporting materials in the growth and regeneration of certain tissues found in muscles and the brain.
“It’s like having billions of tiny 3D printers that fit inside a bottle,” said Luiz Greca, a PhD student at Aalto University. “We can think of the bacteria...