Fabrication And Analytical Application Of Glucose Biosensors

Chapter 1:A biosensor,a device incorporating a biological molecular recognition component connected to a transducer,can output an electronic signal proportional to the concentration of the analyte being sensed.It has become one of the important research fields of analytical chemistry.The working principles,types and characteristics were summarized.Addition, bioactive units immobilized method and its application were briefly reviewed.Chapter 2:A glucose biosensor using a chitosan membrane/GOx/eggshell membrane as biological molecular recognition component and a dissolved oxygen electrode as a transducer was fabricated.The glucose oxidase was entrapped between eggshell membrane and chitosan membrane.In the optimization studies of the biosensor,the most suitable enzyme and chitosan amounts were found to be 0.8mg and 0.30%(w/v),respectively.The phosphate buffer(pH 7,300 mM) and room temperature were chosen as the optimum working conditions.In the optimum condition,the biosensor response has a linear range of glucose concentration between 16μM and 1.10mM with a detection limit of 8μM(S/N=3) and 1 min response time.In the characterization studies of the glucose biosensor,some parameters such as interference effects and storage stability were investigated in detail.When applied to analyze glucose in Wahaha drink,the recovery was 97%～110%. The biosensor exhibits excellent stability.The promising features of our device are simple sensor design and ease of operation.The biosensor provides a fast,reliable,accurate method for the determination of glucose in Wahahaha drink.Chapter 3:Procedure of chemical modified nylon net was studied,and based on the principle of chemical reaction about chemical modification of nylon net,influence of various experimental parameters on activation of nylon net was investigated in detail.It was found that after alkylated with dimethyl sulfate at 60℃for 10 min,reacted with L-lysine as a spacer and glutaraldehyde as a cross-linking reagent for 3 h and 1 h,respectively,the chemical modified nylon net could obtain higher response.Otherwise,the nylon net has high mechanical strength and resistance to microbial attack which make the nylon net to be a kind of good enzyme-immobilized platform.Chapter 4:A glucose biosensor composed of GOx-immobilized nylon net by covalent bonding and a dissolved oxygen electrode as a transducerhas was developed.The detection scheme was based on the depletion of dissolved oxygen level monitored and related to the glucose concentration.The effect of the amount of enzyme loading,pH,concentration and temperature of phosphate buffer on the response of the glucose biosensor has been studied in detail.In the optimum condition,the glucose biosensor had a linear range of 18μM-1.10mM with the detection limit of 9μM(S/N=3) and 80 s response time.It exhibited good operational stability and also had long-term storage stability.When applied to analyze glucose in human serum,the biosensor obtained the data compared well with those of a commercial glucose assay kit, and the recovery was 95%～104%.The biosensor provides a fast,reliable,accurate method for the determination of glucose in human serum.Chapter 5:A biosensor was fabricated by employing eggshell membrane /GOx/Carbon nanotubes/chitosan membrane formed by entrapping glucose oxidase between eggshell membrane and chitosan membrane dispersed with carbon nanotubes and a dissolved oxygen electrode as a transducer.Influence of various experimental parameters on the glucose biosensor was investigated.