The Development of an Amperometric Biosensor Based on the Assembly of Genetically Engineered Enzymes for the Detection of Explosives

Abstract

A series of nitroreductases containing sequences of cysteine amino acids, enabling strong thiolate bonds to form on a gold electrode surface without the loss of enzyme activity, were genetically engineered. The cysteines enable the orientationally controlled immobilisation of the enzymes, removing the need for pre-treatment of the electrode surface with self-assembled monolayers or conducting polymers. The enzymatically modified electrodes were utilised in the development of an amperometric biosensor for the detection of explosives containing nitro-aromatic compounds. Preliminary results demonstrate detection levels down to 5 parts per trillion, signifying tremendous promise towards an in situ sensor for the detection of vapours from explosive compounds.