Imagine a shirt that feels like any other, but could feed you real-time information about your health and surroundings, heat up and cool down automatically, or even track your travels, giving you data on local transport, restaurants and attractions. Now imagine that the same fiber woven into that shirt could be used to treat neurological diseases, and guide robotic surgery. These are some of the very real outcomes of this new ultra-thin computing thread.
Fudan University researchers in Shanghai have managed to build complex electronic circuits within the tiniest of spaces – a flexible fiber thinner than a human hair. They call it a "fiber chip," and it's been more than a decade in the making.
These sorts of smart fibers aren't new – scientists have been working for some time to embed this technology into textiles for unobtrusive connectivity. But one of the hurdles has been getting complex electronics into small spaces like a single strand of cotton. And because computer chips – regardless of how small they can be made – are generally flat and inflexible, they don't exactly lend themselves to the natural feeling and behavior of any sort of fabric.
Here, the scientists moved away from traditional surface-level wearable electronics and instead built circuitry in a layered, spiral form – and placed that inside the actual ultra-thin fiber. In doing so, they were able to create their "fiber chip" that holds 10,000 transistors – the electronic switches that control current flow through a circuit – in just 1 mm of fiber. For context, this is about the same processing capability you'd find in a regular pacemaker. Lengthening that tiny strip of fiber to a meter (3.3 ft) and you could potentially have millions of these transistors, generating the the processing power of a typical desktop computer. So you can imagine what it could be capable of when turned into clothing.
What's more, each strand also houses resistors, capacitors and diodes, forming a complete closed-loop hybrid system capable of processing both digital and analog signals.
"Our fabrication method is highly compatible with the current tools used in the chip industry," said Chen Peining, a researcher at Fudan University's Institute of Fiber Materials and Devices. "We have already achieved a way to mass-produce these fiber chips."
The fibers are not just flexible but thin – around 50 micrometers, (the average human hair is around 70 micrometers in diameter) – which makes them not just great candidates for clothing but also medical applications. As the team outlined in the study, the fibers are flexible like brain tissue, which opens up the possibility of them being used as biocompatible neurological tools, especially in the area of smart implants.
"The human body is made of soft tissue, so emerging fields like future brain-computer interfaces demand soft, compliant electronic systems," Peng Huisheng, who led the study, told Chinese media outlet Xinhua.
The fiber technology – which the team spent more than a decade engineering – could then be used to treat symptoms of Parkinson's disease, epilepsy and stroke, or integrated into tools and used as precision sensors.
"Smart tactile gloves made with fiber chips are indistinguishable from ordinary fabric," Chen said. "They can sense and simulate the feel of different objects, which could be used by surgeons to 'feel' the hardness of tissue during a remote robotic surgery."
While it's one thing to produce such a prototype in the lab, technology like this needs to be both scalable and durable. So the team put it to the test, mimicking real-world treatment and wear and tear. The fibers withstood more than 10,000 cycles of bending and abrasion, stretched up to 30%, were easily twisted, and survived being washed 100 times. They also passed heat (100 °C/212 °F) and compression (to the equivalent of the weight of a 15.6-tonne truck) tests.
Now, the team is working with a hospital in an effort to adapt the fiber chip for use in cardiovascular surgery.
"We hope that one day electronic fabrics built on 'fiber chips' will exchange information as efficiently as today's phones and computers," Chen told Xinhua.
The research was published in the journal Nature.
Source: Fudan University
