Electrochemical sensor containing an enzyme linked to binding molecules

Abstract

An electrochemical sensor is provided containing a supporting material having a surface of noble metal such as gold or palladium to which is bound an enzyme such as glucose oxidase via binding molecules. The binding molecules are in the form of a homogenous monolayer and are bound to the metal surface by anchor groups such as thiol, disulphide or phosphine groups. The enzyme is linked to the binding molecules by an ionic bond, a covalent bond or a metal-chelate bond. The binding molecules may contain a spacer such as an alkylene chain. Coverage of the binding molecules on the metal surface is less than the maximum coverage to optimize enzyme coverage, decrease response time of the sensor and increase signal yield per surface area. The monolayer may contain diluent molecules which are not linked to an enzyme and which are bound to the metal surface via anchor groups. The diluent molecules lower the concentration of binding molecules in the monolayer, increase conductivity of the monolayer and lower unspecific binding of components from a sample solution in contact with the sensor. The binding molecules can be linked by an ionic bond or a metal-chelate bond, respectively, to a charged amino acid residue or a chelate-forming amino acid residue of the N-terminus, C-terminus, or N- and C-terminus of recombinant enzyme protein.