Novel 3D Printing Technique Creates Highly Customized Structures

A team at Aalto University has used bacteria to produce intricately designed three-dimensional objects made of nanocellulose. With their technique, the researchers were able to guide the growth of bacterial colonies through the use of strongly water repellent surfaces. Their results were published in ACS Nano.

The new technique allows fibres—with a diameter a thousand times thinner than a human hair—to be aligned in any orientation, even across layers, and various gradients of thickness and topography, opening up new possibilities for application in tissue regeneration.

"It's like having billions of tiny 3D printers that fit inside a bottle," explains researcher Luiz Greca. "We can think of the bacteria as natural microrobots that take the building blocks provided to them and, with the right input, create complex shapes and structures."

Once in a superhydrophobic mould with water and nutrients, the aerobic bacteria produce nanocellulose. The superhydrophobic surface essentially traps a thin layer of air, which invites the bacteria to create a fibrous biofilm replicating the surface and shape of the mould. With time, the biofilm grows thicker and the objects become stronger.

The nano-sized fibres do not cause adverse reactions when placed in contact to human tissues. The method could also be used to grow realistic models of organs for training surgeons or improving the accuracy of in-vitro testing. "It's really exciting to expand this area of biofabrication that takes advantage of strong cellulose nanofibres and the networks they form. We're exploring applications for age-related tissue degeneration, with this method being a step forward in this and other directions," says lead researcher Orlando Rojas.