Dopamine and glucose electrochemical sensors based on plasma treated plastics
Document typeMaster thesis
Rights accessRestricted access - author's decision
In a recent study, plasma-treated low-density polyethylene (LDPE) modified with adsorbed glucose oxidase (GOx) electrochemical sensor has been developed to promote the electrocatalytic oxidation of glucose. Indeed, GOx catalyses the oxidation of glucose into gluconolactone. A biosensor is composed of three parts: the immobilization surface, the bioreceptor and the transducer. The immobilization surface, in our case the polymer LDPE, avails the immobilization of the bioreceptor onto the sensor. The bioreceptor, in our case the enzyme GOx, promotes the interaction with the analyte in order to produce an effect measurable by the transducer. The transducer, in our case the carbon glassy electrode (CGE), converts the production or consumption of electrons by glucose oxidation into an electrochemical signal. The aim of this project is to develop an electrochemical sensor based on plasma-treated inert and insulating LDPE modified with covalently immobilized GOx for glucose detection. Indeed, covalent immobilization of the enzyme inhibits desorption of GOx and in this way improves the lifespan and the efficiency of the biosensor. Electrochemicalmethods have been used to detect glucose oxidation.In a first part, covalent immobilization of GOx onto the electrode’s surface is detailed. A carboxyl activating agent, 1-(3-(dimethylamino)propyl)-3-ethylcarbodiimide methiodide, is used for the coupling of amines and thus, the immobilization of the enzyme.In a second part, direct detection of glucose by cyclic voltammetry and chronoamperometry is studied. Thanks to these results, limit of detection of the biosensor is pointed out.In a third part, indirect detection of glucose through detection of hydrogen peroxide produced by the redox reaction is explained. This method is a work in progress and further experiments have to be realised in order to improve it.
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