Hollow MnS nanospheres as electron transfer promoters of hemoglobin and their electrochemical sensing applications

Monodispersed hollow MnS nanospheres have been prepared through a solvothermal method using an imidazoline derivative as the morphology-directing reagent. The composition and morphology of synthesized MnS were characterized by powder XRD, SEM, and TEM. The MnS nanospheres were then mixed with chitosan and used as an immobilization matrix for redox protein of hemoglobin. UV–vis and FT-IR spectra showed that the configuration of hemoglobin in the composite film was well maintained. Electrochemical experiments demonstrated that the charge transfer process of Hb was greatly promoted by the MnS. The modified electrode also showed good electrocatalysis toward hydrogen peroxide with the linear range from 0.8 to 15.2 µM. The detection limit and Michaelis–Menten constant were determined to be 0.092 and 4.33 µM, respectively. When the biosensor was utilized for the detection of hydrogen peroxide in contact lens care solution, satisfactory results were obtained.