The use of microelectrodes and microbiosensors in analytical chemistry present some advantages such as: an improved detection limit or the possibility to follow localised phenomena; but their application is limited by difficulties concerning surface modification and enzyme immobilisation. This project aims to develop an adaptable enzyme immobilisation method for the production of microbiosensors. An electrochemical mediator will be electrodeposited on the surface of microelectrodes and subsequently a FAD-dependent enzyme will be immobilised. Modification of the microelectrodes will be realised using techniques that are easily adaptable for electrodes made with other materials or different mediators (e.g. diazonium allows binding to different materials as opposed to thiols which bind only to gold). Modification methods are directed towards the surface of the microelectrodes (e.g. electropolymerisation occurs only on the electrode surface while co-precipitation leads to the deposition of products on the microelectrode support as well). Finally, microbiosensors will be used for monitoring cell cultures. Other possible applications of microelectrode modification methods are in various fields of analytical chemistry such as EAFM and SECM or in improving the performance of fuel cells.