Bioengineers have successfully developed sensors as fine as spider's silk.
Researchers at the University of Cambridge in the UK say the extremely light sensors could be used to monitor human health, such as heartbeats, or to detect detailed changes in the environment.
The sensors are 50 times thinner than human hair and so lightweight that the scientists were able to print the fibre directly onto a dandelion without it collapsing.
In a recently published study, the sensor was tested to pick up signals such as heartbeats in the same way as an electrocardiogram (ECG).
The research team says the sensors are so imperceptible they can be used on babies or animals without them noticing.
"It's really difficult to measure an ECG on a baby, for example, continuously, so that will be a very important application, you put these tiny fibres on, (they) don't interfere with them, and then they can actually, the ECG can be continuously measured,” said Yan Yan Shery Huang, the lead researcher and a bioengineer at University of Cambridge.
“I can think about for animals as well. So if you like some areas (of the skin), you can get rid of the hair of the animal and then put the fibres there and they would not sort of like get to this device," Huang added.
The team tested the bioelectronic fibres on surfaces including a chicken embryo that showed that they were imperceptible while providing a high-quality sensor performance.
According to the team, sensors on one person could pick up signals from someone else on contact.
"If we put the fibres onto, for example, our fingertips and then we touch another person and then we can actually sense the ECG of another person without any wearables. So imagine sort of like doctors can potentially, or maybe mothers, they can actually wear the sensors and touch their babies and sense their ECG signal," said Huang.
The fibre is made of mainly three components – a polymeric material which enables this material to draw into fibre, hyaluronic acid which is similar to human skin enabling the fibre to be in contact with the skin, and a semiconducting polymer which transfers the electrical signal from the body.
‘Extremely small environmental footprint’
Most existing flexible sensors are plastic which can become a biological hazard on disposal. 3D printing is less wasteful but can't print as finely as the bioelectronic fibres containing the biocompatible polymer, hyaluronic acid and polyethylene oxide.
Despite being synthetic, the environmental footprint of manufacturing the fibre is also extremely small, according to the research team.
The novel fibre can be washed away at the end of its use, generating less than a single milligram of waste, comparable to a typical load of laundry which produces between 600 and 1500 milligrams of fibre waste, according to thethe researchers.
They added that the fibre can be made easily on-site. That’s unlike many of existing products that need to be manufactured in expensive “clean rooms” which are costly and create a larger carbon footprint.
"The whole lifecycle of this sensor interface has got very, very little environmental impact. It's like spiders, you can repair them on demand, you can create them anywhere, so without centralised facilities, without using very energy intensive processes, it a very low waste process," says Huang.
In the study, researchers wrote that the fibre could be applied in fields other than healthcare, such as virtual reality or electronic textiles. They could also be used to improve the "sensation of reality" in gaming or as environmental sensors.
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