Life-like 3D synthetic materials move by themselves like worms

Scientists are exploring “active matter,” a type of material that can move independently. Unlike everyday materials like plastic and wood, active matter behaves in a lifelike way.

This is because it’s made of components powered by internal energy sources, which keep them constantly moving. These materials could be used for various applications, like delivering drugs or creating self-healing materials.

Scientists from the University of Bristol, working with colleagues in Paris and Leiden, conducted an experiment with tiny particles called Janus colloids, which are one-millionth of a meter in size and suspended in a liquid mixture. They made the material active by applying a strong electric field and observed the effects using a special microscope that takes three-dimensional images.

Previous studies used larger colloid particles, but by using smaller particles, the researchers could experiment in three dimensions and find interesting results. When the electric field was applied, the scattered colloid particles merged to form worm-like structures, creating a three-dimensional synthetic active matter system.

The researchers discovered that the tiny structures formed self-driven active filaments resembling living worms. They created a theoretical model that allows them to predict and control the movement of these synthetic worms based solely on their lengths.

Co-author Prof Tannie Liverpool added: “While applications in the real world are probably far in the future because these materials can move independently, it could eventually lead to the ability to design devices that independently move different parts of themselves, or the design of swarms of particles that can search for a target, which could have health applications by having specifically targeted medicines and treatments.”

The synthetic worm chains discovered emerge under low-density conditions. At higher densities, the researchers found the particles formed sheet-like and maze-like structures.

Journal Reference:

1. Xichen Chao, Katherine Skipper, C. Patrick Royall, Silke Henkes and Tanniemola B. Liverpool. Traveling Strings of Active Dipolar Colloids. Physical Review Letters. DOI: 10.1103/PhysRevLett.134.018302