Electronic methods for the detection of analytes
The present invention is directed to the detection of target analytes using electronic techniques, particularly AC techniques.
1. A method of detecting a protein target analyte in a sample comprising:
a) applying a first input signal to an assay complex comprising:
i) a redox active complex comprising:
1) a redox active molecule;
2) a binding ligand that will bind said protein target analyte; and
ii) said protein target analyte,
wherein said binding ligand is covalently attached to a first measuring electrode via a spacer, wherein said spacer is attached to said electrode with more than one sulfur moiety, and wherein said first measuring electrode further comprises a passivation agent monolayer comprising at least a covalently attached first passivation species; and
b) detecting a change in the faradaic impedance of the system as a result of the association of the redox active molecule with said protein target analyte, if present.
2. A method according to claim 1 wherein said protein target analyte is an enzyme.
3. A method according to claim 1 wherein said binding ligand is a peptide.
4. A method according to claim 1 wherein said redox active molecule is a transition metal complex.
5. A method according to claim 4 wherein said transition metal complex comprises a transition metal selected from the group consisting of iron, ruthenium and osmium.
6. A method according to claim 4 wherein said transitional metal complex is ferrocene.
7. A method according to claim 1 wherein said spacer is a conductive oligomer.
8. A method according to claim 1 wherein said passivation species is an insulator.