Minuscule pliers made of soft filaments added to the ends of optical fibres can be controlled with visible light, and could be used to grip objects tens of micrometres in size, such as some individual cells.
Piotr Wasylczyk at the University of Warsaw in Poland and his colleagues made the pliers from liquid-crystal elastomer, a soft polymer material. They bend when visible light shines through attached optical fibres.
The texture of the pliers is similar to a very soft rubber, and becomes even softer when the pliers bend, says Wasylczyk.聽Despite the softness of the material, the pliers can grip with a force equivalent to 100 times their weight.
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The researchers created the pliers聽by dipping the ends of optical fibres聽鈥� transparent glass fibres about the thickness of a human hair聽鈥� in a liquid-crystal elastomer.
They then used ultraviolet light to聽set the elastomer: the UV light triggers a reaction that makes the聽material harden. This created cone-shaped tips on the ends of the聽optical fibres.
Shining visible light through the聽optical fibres causes the tips to聽reversibly bend, a process that聽Wasylczyk estimates can be repeated several thousand times before the material eventually breaks. In principle, the tiny pliers聽could be controlled from kilometres away.
鈥淭here are [other] technologies to 3D print different structures in the micrometre scale, but all of them are very complex,鈥� says Wasylczyk. Many need large workstations and聽expensive equipment, and the聽advantage of these tiny pliers is聽their ease of fabrication, he says.
The team wants to scale down the pliers so they could grip objects as small as 1 micrometre in size, such as a bacterium.
Advanced Materials
