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Co-immobilization of enzymes with the help of a dendronized polymer and mesoporous silica nanoparticles

Hanna Gustafsson (Institutionen för kemi och kemiteknik, Teknisk ytkemi) ; A. Küchler ; Krister Holmberg (Institutionen för kemi och kemiteknik, Teknisk ytkemi) ; P. Walde
Journal of Materials Chemistry B (2050-7518). Vol. 3 (2015), 30, p. 6174-6184.
[Artikel, refereegranskad vetenskaplig]

The two enzymes Aspergillus sp. glucose oxidase (GOD) and horseradish peroxidase (HRP) were co-immobilized on solid silica supports in a spatially controlled way by using mesoporous silica nanoparticles (Hiroshima Mesoporous Materials, HMM) and a polycationic dendronized polymer (denpol). The silica support was first coated with the denpol, followed by the deposition of the mesoporous silica nanoparticles into which-in a next step-GOD was adsorbed. Finally, the GOD-loaded silica nanoparticles were coated with a denpol-HRP conjugate constituting of several HRP molecules which were covalently bound to the denpol via bis-aryl hydrazone (BAH) bonds. The entire immobilization process was followed in real time with quartz crystal microbalance with dissipation monitoring (QCM-D). The activities and storage stabilities of the co-immobilized enzymes were determined by analyzing a two-step cascade reaction involving the two immobilized enzymes GOD and HRP. d-glucose and o-phenylenediamine (OPD) were used as substrates for GOD and HRP, respectively. The cascade reaction-in which intermediate hydrogen peroxide was formed from d-glucose and dissolved O2 with GOD-was shown to take place. The immobilized enzymes remained fairly stable for at least 2 weeks if stored in contact with an aqueous solution of pH = 7 at 4°C. If, however, denpol-BAH-GOD coated HRP-loaded mesoporous silica nanoparticles were used (the reversed situation), the cascade reaction was not effective. This was probably due to slow diffusion of hydrogen peroxide from the surface-exposed GOD to the particle-trapped HRP, and/or due to an inefficient loading of active HRP inside the particles. Overall, the combination of two enzyme immobilization methodologies-enzymes adsorbed within mesoporous silica nanoparticles and enzymes adsorbed as denpol-BAH-enzyme conjugates-allows the spatially controlled localization of different types of enzymes in a simple way. Possible applications of the concept are in the field of bioelectrode fabrication.

Denna post skapades 2015-08-21. Senast ändrad 2015-09-17.
CPL Pubid: 220929


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Institutionen för kemi och kemiteknik, Teknisk ytkemi



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