Fluorescent 2D WS₂ Nanosheets Bearing Chemical Affinity Elements for the Recognition of Glycated Hemoglobin

It is required to exfoliate and functionalize 2D transition metal dichalcogenides (TMDs) in an aqueous solution for biological and medical applications. Herein, the approach for the simultaneous exfoliation and functionalization of 2D WS₂ nanosheets using boronic acid-modified poly(vinyl alcohol) (B-PVA) in an aqueous solution is reported, and the B-PVA-functionalized WS₂ nanosheets (B-PVA-WS₂ ) are exploited as a fluorescent biosensor for the detection of glycated hemoglobin, HbA1c. The synthetic B-PVA polymer facilitates the exfoliation and functionalization of WS₂ nanosheets from the bulk counterpart in the aqueous solution via a pulsed sonication process, resulting in fluorescent B-PVA-WS₂ nanohybrids with a specific recognition of HbA1c. The fluorescence of the B-PVA-WS₂ is quenched in the presence of HbA1c, whereas PVA-functionalized WS₂ (PVA-WS₂ ), not bearing boronic acid as a recognition moiety, shows no fluorescence changes upon the addition of the target. The B-PVA-WS₂ is able to selectively detect HbA1c at the concentration as low as 3.3 × 10^-8 m based on its specific fluorescence quenching.