Molybdenum disulfide-integrated photonic barcodes for tumor markers screening

As a new class of two-dimensional (2D) materials, molybdenum disulfide (MoS2) has huge potential in biomedical area; while its applications in multiplex bioassays are still a challenge. Here, we present novel MoS2-integrated silica colloidal crystal barcode (SCCB) for multiplex microRNA (miRNA) screening. MoS2 was adsorbed on SCCBs by electrostatic interaction, and quantum dots (QDs) decorated hairpin probes were coupled on MoS2 by covalent linkage. As the MoS2 could quench the QDs of the hairpin probes, they together formed a molecular beacon (MB) structure before the detection. When used in assays, target miRNA could form a double strand with the probe and made QDs keep away from MoS2 sheets to recovery their fluorescence. Because the released QDs were positively correlated with the concentration of the hybridized nucleic acid, the target miRNAs could be quantified by measuring the fluorescence signal of the QDs on the SCCBs. In addition, by utilizing different MoS2-integrated structural color encoded SCCBs, multiplexed miRNA quantification could also be realized. Based on this strategy, we have demonstrated that several pancreatic cancer-related miRNAs could be selectivity and sensitivity detected with a detection limit of 4.2 +/- 0.3 nM. These features make the MoS2-integrated SCCB ideal for many potential applications.