AC methods for the detection of nucleic acids

• US 6,495,323 B1
• Filed: 09/12/2000
• Issued: 12/17/2002
• Est. Priority Date: 11/05/1996
• Status: Expired due to Term

• Current Assignee: Roche Molecular Systems (Roche Holding AG)
• Original Assignee: Clinical Micro Sensors Inc. (Roche Holding AG)
• Inventors: Kayyem, Jon Faiz, OʼConnor, Stephen D.
• Primary Examiner(s): Jones, W. Gary
• Assistant Examiner(s): Taylor, Janell E.
• Application Number:
  US09/660,374
• Time in Patent Office: 826 Days
• Field of Search: 435/6, 435/5, 536/23.1, 536/24.3, 935/76, 935/77, 935/78
• US Class Current: 435/6.11
• CPC Class Codes: C07H 21/00 Compounds containing two or more mononucleotide units having separate phosphate or polyphosphate groups linked by saccharide radicals of nucleoside groups, e.g. nucleic acids
• CPC Class Codes: C12Q 1/6825 Nucleic acid detection involving sensors

Abstract

The invention relates to nucleic acids covalently coupled to electrodes via conductive oligomers. More particularly, the invention is directed to the site-selective modification of nucleic acids with electron transfer moieties and electrodes to produce a new class of biomaterials, and to methods of making and using them.

Claims

1. A method for detecting the presence of a target sequence in a nucleic acid sample, comprising:

a) applying a first input signal comprising an AC component at a first voltage amplitude to a hybridization complex, said hybridization complex comprising at least a target sequence and a first probe single stranded nucleic acid, said hybridization complex being covalently attached to;

i) a first electron transfer moiety comprising an electrode; and

,

ii) a second electron transfer moiety;

b) applying a second input signal comprising said AC component at a second voltage amplitude to said hybridization complex;

c) detecting the presence of said hybridization complex by receiving an output signal characteristic of electron transfer through said hybridization complex; and

,

d) evaluating the phase shift in said output signal.

2. A method according to claim 1 wherein said output signal is separated into at least two phases.

3. A method according to claim 1 further comprising analyzing said output at one or more phase shifts.

4. A method according to claim 1 wherein said second electron transfer moiety (ETM) is a transition metal complex.

5. A method according to claim 1 wherein said second ETM is a metallocene.

6. A method according to claim 5 wherein said metallocene is ferrocene.

7. A method according to claim 1 wherein said second ETM is an organic electron transfer moiety.

8. A method according to claim 1 wherein said probe nucleic acid contains a plurality of ETMs.

9. A method according to claim 1 further comprising a soluble second probe sequence comprising said second electron transfer moiety, said second probe is hybridized to said target sequence.

10. A method according to claim 1 wherein said electrode further comprises a monolayer.

11. A method according to claim 10 wherein said monolayer is an insulator.

12. A method according to claim 11 wherein said insulator is an alkyl group.

13. A method according to claim 1 wherein said first probe single stranded nucleic acid is attached to said electrode via a spacer.