Protein biomarkers in blood have been widely used in the early diagnosis of disease. However, simultaneous detection of many biomarkers in a single sample remains challenging. Herein, we show that the combination of a sandwich assay and DNA-assisted nanopore sensing could unambiguously identify and quantify several antigens in a mixture. We use five barcode DNAs to label different gold nanoparticles that can selectively bind specific antigens. After the completion of the sandwich assay, barcode DNAs are released and subject to nanopore translocation tests. The distinct current signatures generated by each barcode DNA allow simultaneous quantification of biomarkers at picomolar level in clinical samples. This approach would be very useful for accurate and multiplexed quantification of cancer-associated biomarkers within a very small sample volume, which is critical for non-invasive early diagnosis of cancer.
Keywords: antigens; barcode DNA; biomarkers; multiplexed detection; nanopore sensing.
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