||Recently, transition metal dichalcogenide (TMD) nanosheets with unique optical properties such as outstanding fluorescent emissions and characteristic Raman scattering signals have received great attention in biosensing. To develop TMD-based optical biosensors, its exfoliation and functionalization in an aqueous solution are required. Herein, we reported an effective approach for the simultaneous exfoliation and functionalization of TMDs with synthetic polymers in an aqueous solution. Interestingly, the hybridized TMD nanosheets (H-TMDs) could selectively recognize a specific pathogen without the use of antibodies. The pathogenic bacteria were then quantitatively detected by reading the H-TMD’s strong and characteristic Raman scattering signals.