2D transition metal dichalcogenides with glucan multivalency for antibody-free pathogen recognition

The ability to control the dimensions and properties of nanomaterials is fundamental to the creation of new functions and improvement of their performances in the applications of interest. Herein, we report a strategy based on glucan multivalent interactions for the simultaneous exfoliation and functionalization of two-dimensional transition metal dichalcogenides (TMDs) in an aqueous solution. The multivalent hydrogen bonding of dextran with bulk TMDs (WS 2 , WSe 2 , and MoSe 2 ) in liquid exfoliation effectively produces TMD monolayers with binding multivalency for pathogenic bacteria. Density functional theory simulation reveals that the multivalent hydrogen bonding between dextran and TMD monolayers is very strong and thermodynamically favored (Δ E b = −0.52 eV). The resulting dextran/TMD hybrids (dex-TMDs) exhibit a stronger affinity ( K d = 11 nM) to Escherichia coli O157:H7 ( E. coli ) than E. coli -specific antibodies and aptamers. The dex-TMDs can effectively detect a single copy of E. coli based on their Raman signal. The detection of pathogenic microorganisms is key consideration for safety across a wide range of fields. Here, the authors report on the simultaneous exfoliation and functionalisation of transition metal dichalcogenides with dextran for antibody-free detection of pathogenic Escherichia coli .