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Polyaniline and its composites based biosensor

Author: XueHuaiGuo
Tutor: ShenZhiZuo
School: Zhejiang University
Course: Polymer Chemistry and Physics
Keywords: Biosensor Polyaniline Composites Glucose sensor The apparent Michaelis constant Carbon Nanotubes In situ electrochemical Composite film Bioelectrochemistry response Polyisoprene
CLC: TP212.3
Type: PhD thesis
Year: 2002
Downloads: 760
Quote: 2
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Abstract

Prepared by electrochemical method for the first time with a special selective permeation of polyaniline / polyisoprene composite film, it can in the presence of ascorbic acid to hydrogen peroxide choosing. SEM and electrochemical studies show that the composite film as compared with the polyaniline film, with a more compact structure and a low electrochemical activity. In polyaniline / polyisoprene composite film as a substrate material having a high selectivity successfully prepared glucose biosensor. Sensor can effectively eliminate the electro-active substance (ascorbic acid) interference caused by the measurement, but also has higher operating and storage stability (continuous use 150, chilled after 5 months, no significant decrease in response). Study found that the composite film polyisoprene content of 28.6% for the sensor making the best conditions; immobilization of glucose oxidase, the apparent Michaelis constant for the 11.9mM, enzyme-catalyzed reaction, the apparent activation energy of 41.1 kJ · mol ^{-1 ; measured pH of the solution, the working potential, the use of temperature on the glucose sensor response to a certain extent. Proposed biosensor constructed a new method - in situ electrochemical polymerization. The principle is: in situ in a porous polymer composite conductive polymer membrane, and also of biological molecules in the polymer composite membrane fixed. It combines a porous polymer material and electrochemical biosensor polymerization advantages resulting sensor has both high sensitivity but also has good stability. Prepared using this method for the first time based on the polyaniline / polyacrylonitrile composite film phenol, choline, glucose biosensor. Prepared by the in situ polymerization of phenol electrochemical sensor has excellent handling and storage stability, the life of up to 8 months, is much higher than the results reported in the literature (usually in less than 3 months). The optimal conditions for production of the sensor: polymerization potential 0.48 V, the composite film of polyaniline content of 24%. The optimum condition sensors: operating potential -50 mV, the solution was measured pH 6.5. Benzoic acid to the phenol sensor competitive reversible inhibitory constant of 33.8 μM; pH of the solution have a greater impact on the inhibition, inhibition as the pH is decreased gradually. In addition, the sensor can also be used for the determination of benzoic acid. Found, based on polyaniline / polyacrylonitrile composite film choline choline oxidase electrode is sensitive and stable electrochemical response of biological, the pH of the test solution, the working potential, the use of temperature on enzyme electrode responses are some impact. Choline oxidase immobilized apparent Michaelis constant of 0.61mM, enzyme-catalyzed reaction, the apparent activation energy of 21.4 kJ · mol ^{-1 . Kinetic analysis showed that the mass transfer in favor of the rate-limiting step of the electrode reaction. In situ electrochemical polymerization by the glucose sensor has fast response (response time of less than 30 s), high sensitivity (67.1 mAM ^{-1 cm ^{-2 ), selective Good (ascorbic acid, acetaminophen, L-glutamic acid, glutathione no interference determination of glucose), wide linear range (0.002 ~ 12 mM), etc., up to the detection limit of glucose Bo ten Zhejiang Science Thesis 2 pM. The continuous use of the sensor 100, refrigerated 100 days, the response was not significantly decreased. Glucose sensor for clinical testing, the results were very satisfactory. Electrochemical doping method using an amine oxidase first fixed in polyaniline films prepared polyaniline with Ann oxidase electrode. The electrode histamine Bioelectrochemical fast response (response time is 5 to 205), the electrode reaction by the enzyme kinetically controlled. Amine oxidase immobilized apparent Michaelis constant is 0. Knife * M, optimum PH is 7.3-7 stone, enzyme-catalyzed reaction, the apparent activation energy of 76M · **. Enzyme electrode has good stability, can be used to determine histamine. In addition, the electrochemical properties of the enzyme electrode by cyclic voltammetry and electrochemical impedance spectroscopy. The first time in Singapore-based SWNT as the matrix material covalently immobilized glucose oxidase, and made the first carbon nanotube-based biosensors. Found that carbon nanotubes in concentrated sulfuric acid and concentrated nitric acid mixture, the reaction for 8 hours 50T, like the base of the obtained carbon nanotube production the best choice glucose sensor; film of carbon nanotubes in a phosphate buffer solution shows a stable electrochemical activity. Glucose sensor based on carbon nanotubes has some special properties: it is at a lower potential. 40 V) under diffusion control can be achieved in response to a wide pH range is almost constant. In addition, the life of the sensor is 4 months, compared with a glucose sensor based on graphite electrode twice as high. CNT is expected to become a promising new material for preparing biological sensors.}}}}

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