MoS2 nanosheets for improving analytical performance of lactate biosensors

In this paper, a new 2D lactate electrochemical biosensor was developed.It was based on the incorporation of molybdenum disulfide (MoS 2 ) platelets, obtained by an exfoliation method, onto the surface of a glassy carbon (GC) electrode, together with lactate oxidase enzyme (LOx).For the sensor construction, conditions regarding the exfoliation solvent type, as well as both the size and amount of MoS 2 , were optimized.The biosensor platform (GC/MoS 2 /LOx) was topographically characterized by atomic force microscopy (AFM) and the charge transfer process occurring at the electrode interface was studied by electrochemical impedance spectroscopy (EIS).The GC/MoS 2 /LOx biosensor was applied to the determination of lactate in presence of hydroxymethylferrocene (HMF) as a redox mediator.Electrocatalytic effect of the system MoS 2 /LOx was evaluated by comparing the cyclic voltammetric biosensor response with those obtained for biosensors incorporating only one of the components (MoS 2 or LOx) onto the electrode surface.Biosensors containing both components exhibit the best electrocatalytic response.From the calibration curve obtained at +0.30 V, the following analytical parameters were obtained: linear concentration range from -1 0.056 to 0.77 mM, high sensitivity (6.2 µA mM ), good detection limit (17 µM) and reproducibility (RSD = 4.7%).