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Flexible organic electronics mimic biological mechanosensory nerves

The artificial mechanosensory nerves are composed of three essential components: mechanoreceptors (resistive pressure sensors), neurons (organic ring oscillators), and synapses (organic electrochemical transistors)

Seoul National University | Stanford University - Flexible organic electronics mimic biological mechanosensory nerves

1 Jun 2018 | Editor

Researchers at Seoul National University and Stanford University have developed artificial mechanosensory nerves using flexible organic devices to emulate biological sensory afferent nerves. The researchers used the artificial mechanosensory nerves to control a disabled insect leg and distinguish braille characters.

Compared to conventional digital computers, biological nervous system is powerful for real-world problems, such as visual image processing, voice recognition, tactile sensing, and movement control. This inspired scientists and engineers to work on neuromorphic computing, bioinspired sensors, robot control, and prosthetics.

The previous approaches involved implementations at the software level on conventional digital computers and circuit designs using classical silicon devices which have shown critical issues related to power consumption, cost, and multifunction.

The reported research describes artificial mechanosensory nerves based on flexible organic devices to emulate biological mechanosensory nerves.

"The recently found mechanisms of information processing in biological mechanosensory nerves were adopted in our artificial system."

Zhenan Bao, Professor at Stanford University

The artificial mechanosensory nerves are composed of three essential components: mechanoreceptors (resistive pressure sensors), neurons (organic ring oscillators), and synapses (organic electrochemical transistors). The pressure information from artificial mechanoreceptors can be converted to action potentials through artificial neurons. Multiple action potentials can be integrated into an artificial synapse to actuate biological muscles and recognise braille characters.

Devices that mimic the signal processing and functionality of biological systems can simplify the design of bio-inspired system or reduce power consumption. The researchers said organic devices are advantageous because their functional properties can be tuned, they can be printed on a large area at a low cost, and they are flexible like soft biological systems.

Wentao Xu, a researcher at Seoul National University, and Yeongin Kim and Alex Chortos, graduate students at Stanford University, used their artificial mechanosensory nerves to detect large-scale textures and object movements and distinguish braille characters. They also connected the artificial mechanosensory nerves to motor nerves in a detached insect leg and control muscles.

"Our artificial mechanosensory nerves can be used for bioinspired robots and prosthetics compatible with and comfortable for humans."

"The development of human-like robots and prosthetics that help people with neurological disabilities can benefit from our work."

Tae-Woo Lee, Professor at Seoul National University

A bioinspired flexible organic artificial afferent nerve

Yeongin Kim | Alex Chortos | Wentao Xu | Yuxin Liu | Jin Young Oh | Donghee Son | Jiheong Kang | Amir M. Foudeh | Chenxin Zhu | Yeongjun Lee | Simiao Niu | Jia Liu | Raphael Pfattner | Zhenan Bao | Tae-Woo Lee

Science 01 Jun 2018: Vol. 360 | Issue 6392, pp. 998-1003 | DOI: 10.1126/science.aao0098


The distributed network of receptors, neurons, and synapses in the somatosensory system efficiently processes complex tactile information. We used flexible organic electronics to mimic the functions of a sensory nerve. Our artificial afferent nerve collects pressure information (1 to 80 kilopascals) from clusters of pressure sensors, converts the pressure information into action potentials (0 to 100 hertz) by using ring oscillators, and integrates the action potentials from multiple ring oscillators with a synaptic transistor. Biomimetic hierarchical structures can detect movement of an object, combine simultaneous pressure inputs, and distinguish braille characters. Furthermore, we connected our artificial afferent nerve to motor nerves to construct a hybrid bioelectronic reflex arc to actuate muscles. Our system has potential applications in neurorobotics and neuroprosthetics.

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