Improving the microenvironment for enzyme immobilization at electrodes by hydrophobically modifying chitosan and Nafion® polymers

Controlled Deposition of Structured Polymer Films: Chemical and Rheological Factors in Chitosan Film Formation

“…[1][2][3] Because of chitosan's demonstrated ability to immobilize enzymes in scaffold electrodes 1,2,4 and to provide enzyme stabilizing chemical microenvironments, 1,2,[4][5][6][7][8][9] new information regarding the utility of the spread-coating technique to fabricate micron thin chitosan biopolymer films, in terms of its ability to control film thickness and morphology, could prove of great benefit with regards to the field of enzyme immobilization and the production of chitosan-based biofuel cell electrodes and biosensors.…”

“…For example, deacetylated chitosan can be chemically modified to introduce amphiphilic micellar structure. [5][6][7][8][9]15,16 Introduction of an N-alkyl moiety on the water/acid soluble, hydrophilic polymer backbone yields a hydrophobic side chain, making the polymer amphiphilic, a characteristic that allows micellar structure or soluble aggregates to form. Evidence for the formation of micellar regions in chitosan have been detected via transmission electron microscopy, fluorescence spectroscopy, and static and dynamic light scattering experiments.…”

“…[5][6][7][8][9] Although the formation of micelles depends on entropy, the structure of the micellar regions of chitosan solutions depends on the relative amounts of intra-and intermolecular chemical/electronic interactions as well as key process variables, such as polymer concentration. 3,5,6,15,16 These chemical interactions include hydrogen bonding which occurs between the hydroxyl functional groups of the polymer backbone within a particular polymer strand, between neighboring strands, and with water molecules in the solution. Hydrogen bonding and electrostatic repulsions of the polyelectrolytic backbone, along with van der Waals dispersion forces that are present between all molecules, provides the attractive and repulsive interactions that are responsible for the differences in amounts of intra-and intermolecular aggregation of the hydrophobic side chains along the chitosan backbone.…”

Performances of Enzymatic Glucose/O2 Biofuel Cells

“…Other non-electropolymerized films can be used for enzyme holding. Currently, both chitosan and Nafion ® are commonly used (Habrioux et al, 2010;Klotzbach et al, 2008). These two polymers possess surfactant properties interesting to immobilize enzymes in micellar structures (Moore et al, 2004).…”

“…These two polymers possess surfactant properties interesting to immobilize enzymes in micellar structures (Moore et al, 2004). Moreover, the hydrophobic/hydrophilic property of the polymers can be tuned by modifying the chemical structure of these molecules (Klotzbach et al, 2008;Thomas et al, 2003). It is also possible to simply use retention properties of the Nafion ® film for buffering its sulfonic groups (Habrioux et al, 2010).…”