Venus flytraps can be tricked into snapping shut on command, researchers have shown, effectively turning them into biological robots that can be controlled wirelessly.
The Venus flytrap (Dionaea muscipula) is a carnivorous plant that catches its prey, such as flies, by snapping its circular leaves shut around it. The leaves鈥� edges are studded with thin hairs that generate electrical impulses when an insect touches them 鈥� this burst of electricity causes the trap to close in as little as 0.1 seconds. at Nanyang Technological University in Singapore and his colleagues wondered if they could manipulate the plant into closing the trap without any prey touching it.
They had to find a way to deliver the electrical impulse that initiates the snapping process. Because these plants are fragile and waxy, the researchers had to devise special electrodes that could be stuck to the flytrap鈥檚 leaves without damaging them.
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They made the electrodes from a new kind of hydrogel, a soft and stretchy material like gelatine, combined with a tiny mesh of silver that conducts electricity well. Li says that these new electrodes stayed more securely attached to the plant than electrodes made of silver chloride that plant researchers typically use. They also have lower electrical resistance, so they are more energy-efficient.
Li and his colleagues also equipped the electrodes with a wireless chip, which enabled them to use their phones to snap shut living Venus flytraps. Going a step further, they cut off the flytrap鈥檚 鈥渏aws鈥� and connected them to a robotic arm to make a cyborg. The researchers wirelessly controlled this plant-based robot to pick up platinum wires about half a millimetre in diameter. Li presented the work at the American Physical Society鈥檚 March Meeting in Las Vegas, Nevada, on 6 March.
Manipulating Venus flytraps to open after they have shut is more challenging, the researchers say. The natural process takes up to an hour and there is no way to speed that up with electrical impulses. Li and his colleagues are exploring whether that can be done by somehow boosting the plant鈥檚 metabolism 鈥� for example, by exposing it to very bright light.
