Recent progress in alcohol biosensors

Introduction A biosensor is an analytical tool that comprises two essential components, an immobilized bio-component, in intimate contact with a transducer that converts a biological signal into a measurable electrical signal. Both electrochemical and optical transducers are mainly transduction methods that are employed in biosensor developments. This review summarises the studies carried on ethanol determination based on enzyme biosensors, using alcohol dehydogenase (ADH), alcohol oxidase (AOX) or bi-enzyme system, the various techniques of immobilisation, the transducers used and analytical characteristics for biosensor development are described. Almost all enzyme based ethanol biosensors developed are based on the monitoring of NADH in the case of ADH based biosensor, O2 consumption or H2O2 production in the case of AOX biosensor and H2O2 production in the case of thebienzyme system. Underlying the importance of this review is the fact that alcohol istoxic above certain concentrations and its continuous real time monitoring in clinical, environmental and food related environments is of utmost interest. Conclusion Ethanol can be efficiently determined using enzyme based biosensors, which are simple to assemble and operate. Both electrochemical and optical methods can be exploited, using either modified electrodes or modified optodes. The most promising ethanol biosensors developed up to now are the bi-enzymatic system based on immobilisation of AOX coupled with HRP. Other applications that require fast and reliable methods for alcohol determination will certainly benefit with the commercial development of more enzyme based biosensors.