Nanoscale MoS₂-in-Nanoporous Au Hybrid Structure for Enhancing Electrochemical Sensing

We report the fabrication of nanoscale MoS₂ (nMoS₂) via laser ablation in liquid and its application in electrochemical sensing. The laser ablation process fragments microscale MoS₂ sheets into ~5 nm dots with stable aqueous dispersibility. Electrochemical analysis reveals that nMoS₂ possesses multiple reversible redox states, enabling it to participate in redox cycling reactions that can amplify electrochemical signals. When the nMoS₂ is embedded in an electrochemically inert matrix, a chitosan layer, and subsequently incorporated within a nanostructured Au electrode, the nMoS₂-participating redox cycling reactions are further enhanced by the nanoconfinement effect, leading to synergistic signal amplification. As a model system, this hybrid nMoS₂-in-nanoporous Au electrode demonstrates a 9-fold increase in sensitivity for detecting pyocyanin, a biomarker of Pseudomonas aeruginosa infection, compared with a flat electrode without nMoS₂ loading. This study not only elucidates the redox characteristics of laser-fabricated zero-dimensional transition metal dichalcogenides but also presents a strategy to integrate semiconducting nanomaterials with metallic nanostructures for high-performance electrochemical sensing.