Two dimensional (2D) transition metal dichalcogenides (TMDs) have received considerable attention due to their unique optical characteristics. To exploit the TMD nanosheets as biosensors, it is necessary to exfoliate and functionalize TMDs in an aqueous solution. Herein, we report an effective approach to the simultaneous exfoliation and functionalization of TMD nanosheets with a biocompatible polymer, dextran, in water. The strong multivalent hydrogen bonding (ΔEb = −0.52 eV) between the hydroxyl groups of dextran and the chalcogenides of the TMD nanosheets enabled to effectively exfoliate and functionalize TMD monolayers in water, resulting in TMD/dextran hybrids (dex-TMDs). The resulting dex-TMDs exhibited a stronger affinity to Escherichia coli O157:H7 than E. coli-specific antibodies and aptamers. In addition, the dex-TMDs were able to selectively detect a single copy of Escherichia coli O157:H7 without the use of antibodies. Similarly, dex-TMD can identify Escherichia coli O157:H7 specifically without using antibodies. This new biosensing principle can be expanded to detect a variety of biological molecules.

2D nanosheets with binding multivalency for the optical detection of pathogenic bacteria

2019 Spring National Meeting

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