A method of detecting a polypeptide in a sample comprising the steps of (a) contacting a sample with a first molecular-recognition construct and a second molecular-recognition construct, and (b) detecting an association of the first molecular-recognition construct, the second molecular-recognition construct, and the polypeptide by a detection method; wherein (c) the first molecular-recognition construct is capable of binding to a first epitope of the polypeptide and the second molecular-recognition construct is capable of binding to a second epitope of the polypeptide, (d) the first molecular-recognition construct comprises (i) a first epitope-binding agent that can bind to the first epitope, (ii) a first signaling oligo and (iii) a first label, the first epitope-binding agent being covalently attached to the first signaling oligo via a first flexible linker, and (e) the second molecular-recognition construct comprises (iv) a second epitope binding agent that can bind to the second epitope, (v) a second signaling oligo, which is complementary to the first signaling oligo but which only forms a stable association with the first signaling oligo when brought into close proximity thereto through binding to the polypeptide, and (vi) a second label, the second epitope-binding agent being covalently attached to the second signaling oligo via a second flexible linker, wherein the first and second label produce a different signal when the first molecular-recognition construct, the second molecular recognition construct and the polypeptide associate, thereby bringing the first and second label into close proximity, than they do when the first molecular-recognition construct, the second molecular-recognition construct and the polypeptide are not associated, and further wherein i) the first epitope-binding agent and the second epitope-binding agent are each an aptamer, or ii) the first epitope-binding agent is a double stranded polynucleotide and the second epitope-binding agent is an aptamer, or iii) the first epitope-binding agent is an aptamer and the second epitope-binding agent is an antibody. (a) contacting a sample with a first molecular-recognition construct and a second molecular-recognition construct, and (b) detecting an association of the first molecular-recognition construct, the second molecular-recognition construct, and the polypeptide by a detection method; wherein (c) the first molecular-recognition construct is capable of binding to a first epitope of the polypeptide and the second molecular-recognition construct is capable of binding to a second epitope of the polypeptide, (d) the first molecular-recognition construct comprises (i) a first epitope-binding agent that can bind to the first epitope, (ii) a first signaling oligo and (iii) a first label, the first epitope-binding agent being covalently attached to the first signaling oligo via a first flexible linker, and (e) the second molecular-recognition construct comprises (iv) a second epitope binding agent that can bind to the second epitope, (v) a second signaling oligo, which is complementary to the first signaling oligo but which only forms a stable association with the first signaling oligo when brought into close proximity thereto through binding to the polypeptide, and (vi) a second label, the second epitope-binding agent being covalently attached to the second signaling oligo via a second flexible linker, wherein the first and second label produce a different signal when the first molecular-recognition construct, the second molecular recognition construct and the polypeptide associate, thereby bringing the first and second label into close proximity, than they do when the first molecular-recognition construct, the second molecular-recognition construct and the polypeptide are not associated, and further wherein i) the first epitope-binding agent and the second epitope-binding agent are each an aptamer, or ii) the first epitope-binding agent is a double stranded polynucleotide and the second epitope-binding agent is an aptamer, or iii) the first epitope-binding agent is an aptamer and the second epitope-binding agent is an antibody. i) the first epitope-binding agent and the second epitope-binding agent are each an aptamer, or ii) the first epitope-binding agent is a double stranded polynucleotide and the second epitope-binding agent is an aptamer, or iii) the first epitope-binding agent is an aptamer and the second epitope-binding agent is an antibody.