Basically, there are three levels of biocommunications where electronics and biology could interface: molecular, cellular and skeletal. For any implanted bionic material it is the initial interactions at the biomolecular level that will determine longer term performance. While bionics is often associated with skeletal level enhancements, electronic communication with living cells is of interest with a view to improving the results of tissue engineering or the performance of implants such as bionic ears or eyes.
Pioneer researchers, such as Peter Fromhertz from the Max-Plank-Institute of Biochemistry in Germany, have worked for more than 20 years on interfacing neurons and silicon devices. They are experimenting with individual neurons from different parts of the brain by cultivating them and trying to establish ex vivo neural networks. The goal is to stimulate neurons with electric signals and observe how the live network reacts and modifies itself. These studies could result in valuable findings that improve our understanding of how a neural network modifies its structure during the learning phase and the rules that govern the way synapses and neurites grow. Analysis of the electro-physiological activity of neurons could one day enable scientists to develop artificial prostheses for bypassing injured zones and restore brain functionality, or to realize neuro-diagnostic tools for monitoring the reaction of biological neurons to selected chemical species or newly developed drugs.
Making another step in this direction, researchers in Europe have now demonstrated the possibility of integrating living neural cells and organic semiconductor thin-films made of a few monolayers of pentacene. These results are promising for the development of electronic transducers based on organic field-effect transistors with ultra-thin-films, which may be used for real-time monitoring of biological activities at the level of interconnected living cells.
"Monitoring electrical and chemical signaling within neural networks is a fundamental issue in neuroscience" Dr. Fabio Biscarini explains to Nanowerk. "Extracellular metal electrodes can record network activity, but the resolution is too poor to record individual cell responses or single chemical events. The widely used patch clamp approach provides a highly sensitive method for the detection of single cell responses or channel reactions both in vivo and in vitro, but it only allows real-time monitoring for one or very few cells and it is difficult to upscale in number as well as downscale in size."
"A less invasive approach consists of coupling neurons to inorganic semiconductor devices, such as field effect transistors," continues Biscarini, a research scientist at the Institute for the Study of Nanostructured Materials (CNR) in Bologna, Italy. "Although important observ