Simultaneous Sensing of Multiple Cancer Biomarkers by a Single DNA Nanoprobe in a Nanopore

Both vascular endothelial growth factor (VEGF) and matrix metallopeptidase-9 (MMP-9) are key biomarkers in tumor angiogenesis. Determination of the overexpression of the two biomarkers would provide valuable information on the progression of tumor growth and metastasis, but their simultaneous quantification by a single probe is unprecedented. Here, we develop a triplex DNA-based nanoprobe for simultaneously quantifying VEGF and MMP-9 using an α-hemolysin nanopore. A DNA aptamer is used as the triplex molecular beacon (tMB) loop to bind VEGF, and a stem-forming oligonucleotide modified with a short peptide is used to recognize MMP-9. The sequential presence of VEGF and MMP-9 could also be identified by different patterns of current events. Besides, the characteristic current events generated by the DNA probe possess pH-dependent patterns that can be used to reflect the environmental pH. Success in the construction of such DNA nanoprobes will greatly facilitate the investigation of the mechanisms of different tumor angiogenesis processes and provide a useful approach for cancer diagnosis.