Methods for the electrochemical detection of multiple target compounds

A microelectronic device useful for the electrochemical detection of at least two different members of at least two different binding pairs, said device comprising:

• a microelectronic substrate;
• a conductive oxidation-reduction detection electrode on said substrate;
• a first member of a first specific binding pair immobilized on a non-conductive layer, which first member binds with a second member of the first specific binding pair present in a sample, said first member of said first binding pair being adjacent said detection electrode so that an oxidation-reduction reaction occurring upon application of a potential to the detection electrode is detectable;
• and
• a first member of a second specific binding pair immobilized on a non-conductive layer that binds with a second member of the second specific binding pair present in a sample, said first member of said second binding pair being adjacent said detection electrode so that an oxidation-reduction reaction occurring upon application of a potential to the detection electrode is detectable;
• wherein said first member of said first binding pair and said first member of said second binding pair are different.

A method of detecting at least two different hybridization events through a common electrode, comprising the steps of:

• (a) providing a device comprising:
• a microelectronic substrate;
• a conductive oxidation-reduction detection electrode on said substrate;
• a first member of a first specific binding pair immobilized on a non-conductive layer that binds with a second member of the first specific binding pair present in a sample, said first member of said first binding pair being adjacent said detection electrode so that an oxidation-reduction reaction occurring upon application of a potential to the detection electrode is detectable;
• and
• a first member of a second specific binding pair immobilized on a non-conductive layer that binds with a second member of the second specific binding pair present in a sample, said first member of said second binding pair being adjacent said detection electrode so that an oxidation-reduction reaction occurring upon application of a potential to the detection electrode is detectable;
• wherein said first member of said first binding pair and said first member of said second binding pair are different;
• wherein said second member of said first binding pair comprises a first preselected label and said second member of said second binding pair comprises a second preselected label;
• and wherein said first and second preselected labels are different;
• (b) contacting a sample suspected of containing said second member of said first binding pair and said second member of said second binding pair;
• (c) simultaneously contacting to said substrate (i) a first transition metal complex that oxidizes said first preselected label in an oxidation-reduction reaction under conditions that cause a first oxidation-reduction reaction between the first transition metal complex and the first preselected label and (ii) a second transition metal complex that oxidizes said first and second preselected labels in an oxidation-reduction reaction under conditions that cause a second oxidation-reduction reaction between said second transition metal catalyst and the second preselected label, from which preselected labels there is electron transfer to the transition metal complex, resulting in regeneration of the reduced form of the corresponding transition metal complex as part of a catalytic cycle, and with said first and second oxidation-reduction reactions producing different detectable signals;
• (d) detecting the presence of said second member of said first binding pair from the detection of said first oxidation-reduction reaction;
• and
• (e) detecting the presence of said second member of said second binding pair from the detection of said second oxidation-reduction reaction.