We report on a direct communication of two disconnected nerve cells by a semiconductor chip with integrated circuitry. Two neurons from the pond snail Lymnaea stagnalis were separately placed on a silicon chip with microstructures for noninvasive electronic recording and stimulation. When one neuron fired an action potential, its activity was detected by a transistor underneath. The response was transformed on the chip to a digital signal. Passing a delay line, it triggered a burst of voltage pulses that was applied to a capacitive microstimulator on the chip under the second neuron. There an action potential was elicited. Crosstalk in the chip from stimulator to transistor was eliminated by a refractory circuit. The silicon chip plays the role of a prosthetic interneuron that may supplement neuronal circuits. The pathway neuron-silicon-neuron is an elementary step towards the integration of neuronal dynamics and digital electronics on a microscopic level.
Fig. 2: Neurochip. (A) Micrograph of a silicon chip with an all-silica surface. Two snail neurons are attached to two two-way interface contacts. The source (S), drain (D) and gate (G) of a transistor, and the wings of a capacitive stimulator (CSt) are marked. The surface of the chip is made of silicon dioxide. The bright rectangle is the area of thin oxide. (B) Scanning electron micrograph of silicon chip with four pairs of neurons on two-way contacts. The dark rectangles are the areas of thin oxide. (C) Perspex chamber with chip. The interface unit forms the bottom of the chamber in contact to the culture medium. The processor unit is bonded in direct contact, protected from the electrolyte.
rss
Top
Print