▎ 摘　　要

NOVELTY - Detecting (M1) antigen in sample, involves providing first nanoparticle composition having first nanoparticle, first quantum dots and first antibody; providing second nanoparticle composition having second nanoparticle, second quantum dots and second antibody; providing graphene oxide-coated electrode; contacting sample with electrode; contacting electrode with first/second nanoparticle composition; and detecting presence of antigen in sample by detecting property of first/second quantum dots bound to electrode by way of antigen, third antibody and first or second antibody. USE - For detecting at least one antigen in a sample, where the antigen is GPC3 antigen and an EpCAM antigen (claimed). ADVANTAGE - The method provides sensitive and specific assays for cells, particularly quantitative and qualitative assays that can detect and/or measure antigens on sensitive and specific assays for cells, in particular quantitative and qualitative assays that can detect and/or measure antigens on circulating tumor cells (CTCs) at low concentrations in a sample, and for assays that enable the elution of bound tumor cells at low concentrations in a sample, and for assays that enable the elution of bound tumor cells. DETAILED DESCRIPTION - Detecting (M1) at least one antigen in a sample, involves (i) providing a first nanoparticle composition comprising at least a first nanoparticle, a first several quantum dots and a first antibody, where the first antibody is capable of binding to the antigen and where the first quantum dots and the first antibody are attached to the first nanoparticle; (ii) providing a second nanoparticle composition comprising at least a second nanoparticle, a second several quantum dots and a second antibody, where the second antibody is capable of binding to the one antigen and where the second quantum dots and the second antibody are attached to the second nanoparticle; (iii) providing a graphene oxide-coated electrode, where the electrode is attached to a third antibody capable of binding to the antigen; (iv) contacting the sample with the electrode; (v) contacting the electrode with the first nanoparticle composition and the second nanoparticle composition; and (vi) subsequently detecting the presence of the antigen in the sample by detecting at least one property of each of the first and second several quantum dots bound to the electrode by way of the antigen, at least one third antibody and at least one first or second antibody, where the first quantum dots differs from the second quantum dots and the first antibody differs from the second antibody, and the graphene oxide coating on the electrode has been electrochemically reduced. INDEPENDENT CLAIMS are included for the following: (1) an apparatus (S1) for use in the method (M1), comprising a graphene oxide-coated electrode and several of third antibody capable of binding to at least one antigen, where the several of third antibody is attached to the electrode and the graphene oxide coating on the electrode having been electrochemically reduced; and (2) a kit of parts for use in the method (M1), comprising the apparatus (A1); a first nanoparticle composition comprising a first nanoparticle, a first quantum dots and a first antibody, where the first antibody is capable of binding to at least one antigen and where the first quantum dots and the first antibody are attached to the first nanoparticle; and a second nanoparticle composition comprising a second nanoparticle, a second quantum dots and a second antibody, where the second antibody is capable of binding to the antigen and where the second quantum dots and the second antibody are attached to the second nanoparticle, where the first quantum dots differs from the second quantum dots and the first antibody differs from the second antibody.