Researchers at Infineon Technologies have succeeded in connecting a newly developed biosensor chip to living nerve cells and reading electrical signals produced by the cells.
According to Infineon, this breakthrough technology, dubbed the ‘Neuro-Chip’, will allow scientific researchers to gain new insights into the biologic function of neurons, nerve tissue, and organic neural networks. In the field of drug development, the Neuro-Chip will enable tests of the effects of new pharmaceutical compounds on living neurons.
Working with the Max Planck Institute of Biochemistry, Infineon’s project partner, the researchers recorded electrical signals from the neurons from snail brains. Neurons are the specialised cells that make up the nervous systems of all living things. Nerve tissues, comprised of many associated nerve cells, are the principal component of the brain and spinal cord. Nerve cells communicate with each other through electrical pulses, so the ability to read these signals and record them in a computer system holds the promise of new insights into neurological processes.
The Infineon Neuro-Chip is said to integrate 128 x 128 sensors in an array pattern covering one square millimetre. An electronic circuit is integrated below each sensor, which amplifies and processes the extremely weak signals of neurons. Individual neurons are placed into a nutrient solution above the sensor array, which keeps the neurons alive and allows reconstruction of nerve tissue.
Compared to traditional methods of research, in which neurons are damaged in the preparation of study samples, undisturbed observation of nerve tissue over a period of several weeks offers scientists a continuous insight into the functionality of how the nervous system and brain processes work.
The sensor density of the Infineon Neuro-Chip is approximately 300 times greater than today’s common methods for studying neurons, which use glass substrates with vapour-deposited metallic lanes to contact the neuron.
The sensors on each chip are separated by eight micrometers (a thousandth of a millimetre). Since the typical size of neurons is between 10 – 50 micrometers, low-density sensors may not establish a reliable contact. The high-density sensor array of the Neuro-Chip assures that each neuron in a sample is contacted by at least one sensor.
Instead of sequentially checking every single neuron, the Infineon Neuro-Chip surveys several neurons at the same time. Additionally, the Neuro-Chip enables recording of the operating sequence of electrical activity within nerve tissue over a defined time. Every second, the Neuro-Chip can record more than 2,000 single values for each of its 16,384 sensors. The data can then be transformed into a colour picture for visual analysis. Researchers can detect from this data how complete nerve tissues react to electrical stimulation or certain chemical substances in a given period of time.
The total area of Infineon’s Neuro-Chip measures five millimetres by six millimetres, including the circuitry required to amplify and process the neuron signals and transmit the data off-chip. The chip is based on a standard Complementary Metal Oxide Semiconductor (CMOS) technology extended with additional process steps to realise the capacitive sensors array.
‘Infineon’s development of cutting edge microelectronics may be a pre-condition for unheard of applications in the field of biomedicine, biotechnology and brain research,’ commented Professor Dr. Peter Fromherz, Director of the Max Planck Institute for Biochemistry in Martinsried, Germany.