An amperometric silicon-based biosensor for d-lactate

A miniaturised biosensor for d-lactate has been fabricated on silicon wafer. Microsystems technologies led to enhanced efficiency in terms of sample size and reagent consumption while equally allowing mass production. The biosensor is based on the association of an enzymatic solution including diaphorase and d-lactate dehydrogenase confined in the microstructure by a membrane and two weakly polarised gold microelectrodes. Various electrochemical pretreatments of the gold surface are performed to increase the deviceʹs sensitivity. Depending on the geometry involved, the proposed biosensor features a response time ranging from 2 to 5 min, a sensitivity of 2 or 8 μA mM−1 cm−2 and a linearity range from 5×10−3 to 1.5 mmol l−1. Its lifetime is 3 weeks with 10 assays/day.