A miniaturised silicon based enzymatic biosensor: towards a generic structure and technology for multi-analytes assays

A miniaturised and generic biosensor has been developed using microsystem technologies for l- and d-lactate, l-malate, l-alanine and ethanol assays. The biosensor is based on the association between an enzymatic solution including diaphorase and dehydrogenases enzymes confined in the microstructure by a membrane and two gold microelectrodes weakly polarised. The pre-treatment of the gold electrode surface is a critical parameter, the sensor sensitivity can be significantly enhanced by processing chemical cleaning steps with sulphochromic solution, H2SO4+H2O2 solution or oxygen plasma. X-ray photoelectron spectroscopy (XPS) analyses put in evidence that the enhanced sensitivity of electrodes can be in part attributed to the removal of an organic contamination. The assays of l-lactate, ethanol and alanine are also presented and compared to d-lactate assay.