Patent ID: 7001721

Claim:
A method for determining the presence or absence of a target nucleic acid sequence in a sample nucleic acid, the method comprising: (a) exposing the sample to a detection agent comprising at least two separate components, including a first agent having a metal surface associated with a first target binding species (TBS) and a second agent having a metal surface associated with a second TBS, different from said first TBS, at least one of said metal surfaces being associated with a SER(R)S-active species (SAS), each of said first and second TBS being effective to bind to the target sequence, and wherein the binding of the first and second TBS to the target sequence causes aggregation of the metal surfaces associated with said TBS, thereby causing surface enhancement of a SAS associated with one or both of the metal surfaces, said metal surfaces being ineffective to cause surface enhancement in the form in which they are present in the detection agent to which said sample is exposed, and aggregation of said metal SER(R)S surface being dependent on the presence of said target nucleic acid in said sample; and, (b) observing the sample/agent mixture using SER(R)S to detect any said surface enhancement.