Researchers are working on edible computer chips to control robots that can operate inside the human body to precisely deliver drugs before safely being digested.
Medical robots controlled by edible computer chips could deliver drugs inside the body, say researchers. Similar robots could also be used to deliver drugs or vital nutrients to at-risk animals and then naturally biodegrade.
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| A microfluidic logic gate made from ethyl cellulose Laboratory of intelligent systems at EPFL |
Soft robots that can operate inside the human body are a busy area of research, but they tend to be remotely controlled from outside the body with magnets. Simple computers made from flexible tubes and devices that operate hydraulically – known as microfluidic computers – have been in development for some time to give these robots more ability, but they tend to be made from materials such as silicon that can’t be digested.
Shuhang Zhang at the Swiss Federal Institute of Technology Lausanne and his colleagues are investigating how to create those same designs from material that is safe to eat, as part of a wider project called RoboFood where other teams are working on edible batteries, sensors and actuators.
They created a single NOT logic gate – one of the fundamental building blocks that all computer chips are made of – from ethyl cellulose, which is commonly used to create the shell of pills. In the right combination and number, such gates could be used to build simple computers.
A NOT gate takes an input and converts it into the opposite value. The team’s prototype gate is around 2 centimetres square, but Zhang says he hopes to miniaturise it in future experiments.
It consists of three layers and has two input tubes: one that provides a continuous flow of pressure, like a power supply, and another that represents the data input. When a high-pressure input is supplied – representing a 1 inside a classical computer – a valve is forced shut and the output tube has a low pressure, representing a 0 in a classical computer. When a low-pressure input is supplied, representing a 0, the valve opens and the logic gate produces a high-pressure output, representing a 1.
The chip was used in experiments outside the body, but the researchers hope to build more complex logic gates and eventually combine them into devices that will work inside the body autonomously.
“We can just combine these basic NOT gates to produce more complex functions. Our target is to build something that works outside the body, and after that something that could be swallowed – but not chewed, to keep the integrity of the structure – that works inside our body,” says Zhang.
Other research around edible computer chips has even raised the prospect of food that moves or changes taste and colour. But Zhang says that medical and environmental applications are the priority, particularly because the chip currently doesn’t taste very pleasant. “It tastes like wax – beeswax or soy wax.”
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