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Functional Design of Electrochemical Biosensors Using Polypyrrole
Author(s) -
PREETHICHANDRA DALUWATHU MULLA GAMAGE,
ONODA MITSUYOSHI
Publication year - 2016
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.11829
Subject(s) - polypyrrole , biosensor , adsorption , glucose oxidase , amperometry , polymerization , electrode , materials science , immobilized enzyme , pyrrole , electrochemistry , conductive polymer , monomer , linear range , analytical chemistry (journal) , chemistry , nuclear chemistry , polymer , chromatography , nanotechnology , detection limit , organic chemistry , composite material , enzyme
SUMMARY In order to improve biosensor performance, namely, the sensitivity, response time, and linear range values, novel amperometric polypyrrole (PPy) glucose biosensors, achieved by three different immobilizing techniques, namely, physical adsorption, coentrapment, and a two‐step method of coentrapment with superimposed physical adsorption, have been studied. Different enzyme loading and material properties resulted in varied immobilizing techniques, leading to dissimilarities in characteristics. In this study, Pt coated Anodiscs TM with 0.2 μm maximum pore size were used as electrodes to polymerize PPy at 0.3 mAcm −2 using a solution containing 0.05 mol/L pyrrole and 0.1 M NaPF 6 . The polymerization time was optimized to 90 s. In the coentrapment method, glucose oxidase (GOx) (1 mg/mL) was added to the monomer solution while an aliquot of GOx (5 μL) was placed on the prepolymerized electrode for physical adsorption. A combination of these two techniques was used as the last immobilization technique. The physical adsorption method gave a sensitivity of 3 mAcm −2 (mol/L) −1 and a linear range of 0.5 × 10 −3 mol/L to 13 × 10 −3 mol/L with a response time of 3 s. The sensitivity in the case of coentrapment was 3.75 mAcm −2 (mol/L) −1 , while the value was 4.45 mAcm −2 (mol/L) −1 in two‐step immobilization, thus giving 25% and 48% increases, respectively. The response times of 9 s and 8 s in the latter cases reveal possible repercussion taking place in enzyme immobilization in a three‐dimensional (3D) PPy matrix and a delay in the time required for glucose to reach the enzyme. The linear range of the two‐step method was extended to 16 × 10 −3 mol/L by reinforced enzyme loading.