Immobilization of glucose oxidase to nanostructured films of polystyrene-block-poly(2-vinylpyridine)

• AFM and ellipsometry used to characterize thin-films of (PS-b-P2VP).
• Model describing the optical properties of the substrates.
• GOx immobilized on the block copolymer by means of adsorption and entrapment.
• Highest enzymatic activity obtained with the nanoporous PS-b-P2VP substrate.

A critical step for the development of biosensors is the immobilization of the biorecognition element to the surface of a substrate. Among other materials that can be used as substrates, block copolymers have the untapped potential to provide significant advantages for the immobilization of proteins. To explore such possibility, this manuscript describes the fabrication and characterization of thin-films of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP). These films were then used to investigate the immobilization of glucose oxidase, a model enzyme for the development of biosensors. According to the results presented, the nanoporous films can provide significant increases in surface area of the substrate and the immobilization of larger amounts of active enzyme. The characterization of the substrate-enzyme interface discussed in the manuscript aims to provide critical information about relationship between the surface (material, geometry, and density of pores), the protein structure, and the immobilization conditions (pH, and protein concentration) required to improve the catalytic activity and stability of the enzymes. A maximum normalized activity of 3300 ± 700 U m−2 was achieved for the nanoporous film of PS-b-P2VP.

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