MICROELECTRONIC AND NANOELECTRONIC INTERFACING TECHNIQUES FOR BIOLOGICAL-SYSTEMS

A variety of electronic and opto-electronic interfacing techniques for the transduction of biological signals is available which utilise technology normally accessed for microelectronic and nanoelectronic semiconductor device fabrication. Correct interfacing of electronics to biological systems leads to the possibility of creating a range of devices which are capable of being used as biosensors or as monitoring units for individual biological cells. This can be thought of as 'bioelectronic interfacing'. Fabrication of these devices at the microelectronic scale leads to the creation of multi-analyte sensors or electrode arrays 'on chip'. There are many application areas for these devices, ranging from disposable multi-analyte sensors for use in the general practitioner's office to novel research tools allowing the monitoring of networks of neural cells in vitro. The Bioelectronics Research Group at the University of Glasgow has fabricated and tested multi-microelectrode devices for monitoring biological cells in culture. Electrical signals have been recorded extracellularly from individual neural and cardiac cells in vitro; the adhesion and movement of individual cells have been monitored on microelectrodes via electrical impedance techniques. The devices can be adapted as multi-analyte biosensors by immobilising a range of biological molecules on the electrode array. It is possible to further utilise micro- and nano-fabrication techniques to provide patterned molecular arrays for sensors, cell guidance or molecular electronic applications on planar surfaces. One important future application of this might be in nerve repair where guidance cues could be provided for nerve regrowth on surfaces and some examples of this will be shown. At the smallest scale, we are now trying to image and interact with biological molecules on these surfaces using scanning tunnelling microscopy. Possible benefits of this might be better fabrication and immobilisation of molecules for biosensors and the optimisation of surface biocompatibility treatment.