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Sequential pH‐Dependent Adsorption of Ionic Amphiphilic Diblock Copolymer Micelles and Choline Oxidase Onto Conductive Substrates: Toward the Design of Biosensors
Author(s) -
Sigolaeva Larisa V.,
Günther Ulrike,
Pergushov Dmitry V.,
Gladyr Snezhana Yu.,
Kurochkin Ilya N.,
Schacher Felix H.
Publication year - 2014
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.201300580
Subject(s) - choline oxidase , biosensor , adsorption , glutaraldehyde , micelle , chemical engineering , copolymer , methacrylate , immobilized enzyme , polymer , polymer chemistry , materials science , amphiphile , protein adsorption , chemistry , ionic strength , glucose oxidase , nanotechnology , organic chemistry , aqueous solution , enzyme , engineering , acetylcholinesterase
This work examines the fabrication regime and the properties of polymer–enzyme thin‐films adsorbed onto conductive substrates (graphite or gold). The films are formed via two‐steps, sequential adsorption of poly( n ‐butylmethacrylate)‐ block ‐poly( N,N‐ dimethylaminoethyl methacrylate) (P n BMA‐ b ‐PDMAEMA) diblock copolymer micelles (1st step of adsorption), followed by the enzyme choline oxidase (ChO) (2nd step of adsorption). The solution properties of both adsorbed components are studied and the pH‐dependent step‐by‐step fabrication of polymer–enzyme biosensor coatings reveals rather drastic differences in their enzymatic activities in dependence on the pH of both adsorption steps. The resulting hybrid thin‐films represent highly active biosensors for choline with a low detection limit of 30 n M and a good linearity in a range between 30 n M and 100 μ M . The sensitivity is found to be 175 μA m M −1 cm −2 and the operational stability of the polymer–enzyme thin‐films can be additionally improved via enzyme‐to‐enzyme crosslinking with glutaraldehyde.