Abstract: A pH-sensitive monomethoxypoly(ethylene glycol)-grafted-chitosan(mPEG-g-CS) film was used as a matrix for reversible immobilization of cytochrome c(Cyt c) on a Au surface through a novel electrodeposition process. The pH-sensitive behavior of the mPEG-g-CS film was demonstrated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) measurements. Electrochemical-co-deposited Cyt c and mPEG-g-CS exhibited the direct electrochemical behavior which implied that mPEG-g-CS could well control the delivery of Cyt c under different pH.

Key words: monomethoxypoly(ethylene glycol)-grafted-chitosan, pH sensitivity, cytochrome c, direct chemistry, controlled delivery