A Nanomechanical Genosensor Using Functionalized Cantilevers to Detect the Cancer Biomarkers miRNA-203 and miRNA-205

We report a nanomechanical genosensor based on an atomic force microscope (AFM) cantilever functionalized with complementary strands of miRNA-203 and miRNA-205, which are potential biomarkers of metastasis in head and neck squamous cell carcinomas (HNSCC), especially in cervical lymph nodes. Hybridization with the corresponding complementary strand led to cantilever deflections that increased almost linearly with the concentration of either miRNA-203 or miRNA-205 in the fluid cell where AFM experiments were made. The detection limit was ca. 95 nM and 97 nM for miRNA-203 or miRNA-205, respectively, with higher deflections observed for miRNA-205 due to the larger number of interaction groups during hybridization. Selectivity was proven by measuring negligible cantilever deflections for non-specific miRNA sequences. The cantilever functionalization process during genosensor design was confirmed by fluorescence microscopy and AFM imaging. The use of a single genosensor platform for detecting different miRNA molecules is advantageous for diagnosis and prognosis of cases where multiple biomarkers may be relevant, as in the case of HNSCC metastasis.