New microchip – direct connection of electronics and living cells
Specialists of the Interuniversity Center for Microelectronics IMEC (Louvain, Belgium) have created a unique microchip, the surface of which is covered with microscopic needle structures, which provides direct interaction of electronic devices and living cells. The new chip is a mass-produced and easy-to-use device for conducting electrophysiological studies, for example, studying the normal functioning of brain cells and its disorders.
The picture shows a three–day culture of cortical neurons on the surface of a micro-needle chip.
Each microneedle is a place of close contact with the cell surface. An electrode embedded inside such a structure can register or stimulate the electrical activity of an individual cell with high accuracy in real time.
Cells with electrogenic properties – such as cardiomyocytes and neurons– use electrical signals to interact with each other. Knowledge of the parameters of the electrical activity of these cells is necessary to understand the principles of interaction, violations of which underlie the development of diseases such as Alzheimer's and Parkinson's diseases. In addition, monitoring of electrical activity can be used to evaluate the effectiveness of drugs for the treatment of heart diseases and other pathologies.
The new micro-needle chip is an ideal tool for studying intercellular interactions. The electrodes used in its manufacture are smaller in size than the cells and are the thinnest oxidized metal (for example, gold or made of titanium nitride) rods with an unoxidized electrically conductive working part. Upon contact with the chip surface, the cell membrane tightly covers the needle structures, ensuring good contact with the electrode. Such close contact reduces the signal-to-noise ratio, enabling the stimulation of an individual cell and the accurate recording of electrical signals generated by cells.
To turn their idea into reality, the developers had to solve several difficult tasks: to ensure the viability of cells located on the surface of the chip, the ability of the electronic device to work in a culture medium and the tightest possible contact between the cell membrane and the surface of the electrode, as well as to direct cell growth so that the cell body is exactly at the top of the individual electrode.
According to Kris Verstreken, head of the bio-nanoelectronics department at IMEC, very little is known about the functioning of the brain today. How are our emotions formed? How are memories preserved? What causes the development of diseases such as Alzheimer's disease and Parkinson's disease? Most of the processes taking place in our brain remain a mystery to us. Neurons are very plastic cells, constantly forming new intercellular contacts, simultaneously breaking or restoring old ones. However, it is not known how they do it, and what happens during training and development.
In the future, we will be able to use the knowledge gained in laboratory experiments using a new microchip to diagnose diseases and, perhaps, even to treat them by stimulating cells or forming new intercellular contacts instead of destroyed ones, for example, in stroke.
Evgenia Ryabtseva, Alexander Chubenko
Portal "Eternal youth" http://vechnayamolodost.ru based on IMEC materials: Unique Micronail Chip Makes Electronics and Bio Cells Communicate.
30.11.2009