UNLABELLED - A rapid, single-step, solution-phase method for quantifying multiple proteomic biomarkers is described. Nanoscale quantum dot-antibody conjugates self-assemble into microscale aggregates in the presence of a specific antigen through antibody-antigen molecular recognition. These aggregates are easily discriminated from the individual components by flow cytometry. Quantum dot (QD) aggregates can be quantified and correlated to the antigen concentration. Two QD populations with distinct emission spectra are used for detecting two proteomics antigens in a single reaction volume. Multiplexed detection of vascular endothelial growth factor A and angiopoietin-2 is demonstrated at the physiologically relevant, picomolar concentration range. Nonmultiplexed detection of the antigens is also demonstrated, with a femtomolar sensitivity limit. This technique may be optimized for low-cost early detection and frequent screening of cancers and other diseases as well as detection of the biological response to therapy.
FROM THE CLINICAL EDITOR - In this paper a rapid, single-step, solution-phase method is described with multiplexed detection at physiological relevant picomolar concentration range and nonmultiplexed detection with a femtomolar sensitivity limit. The technique may enable low-cost early detection of cancers and other diseases as well as detection of the biological response to therapy.