Development of an amperometric biosensor for lactate

A gold enzyme electrode for lactate, fabricated on silicon has been developed. Standard silicon processing and micromachining techniques have been applied to the fabrication of three sensor types. Two planar types and a containment sensor are presented. The enzyme lactate oxidase (LOx) was immobilised in a suitable matrix and placed on a planar gold electrode or in a gold coated, KOH etched silicon cavity. Activity and stability of the enzyme LOx was assessed in a modified BSA gel and two sol gel matrices. The enzyme has shown above average stability of three months, stored dry, when immobilised in a sol gel matrix. The modified BSA gel also showed potential for use with a gold enzyme electrode. A three electrode configuration in the amperometric mode was used to detect lactate. A linear range of up to 10 mM lactate has been observed using a sol gel as an immobilisation matrix, and a response time as low as 40 seconds. A modified BSA gel has shown a linear range of up to 12 mM lactate. Lactate has also been successfully detected using the containment sensor.