Issue 14, 2010

In situ quantitative visualization and characterization of chitosan electrodeposition with paired sidewall electrodes

Abstract

We report the first in situ quantitative visualization and characterization of electro-induced chitosan hydrogel growth in an aqueous environment. This was enabled with a pair of sidewall electrodes within a transparent fluidic system, which allowed us to resolve the electrogelling mechanism and interpret the dominant causes responsible for the formation and density distribution of the deposited hydrogel. The pH and the time-dependent growth profiles of the chitosan hydrogel were directly visualized, analyzed, and characterized. The results indicate that the gelation and immobilization of chitosan onto the cathode at a pH above its pKa value (∼6.3) are due to the electrochemically generated concentration gradient of reactant OH ions, and their subsequent neutralization of the NH3+ groups of chitosan chains in solution near the cathode. The increased gel density around the fringes of the electrodes was demonstrated and correlated with the electrophoretic migration of chitosan cations during deposition. Simulation of the electric potential/field distribution, together with the corresponding dry film topography confirmed the non-uniform, electric field-dependent density distribution of deposited hydrogel. This report provides fundamental understanding towards the mechanism and the kinetics of the electro-induced chitosan gel formation. It also provides important guidelines for pursuing its application in bio-components integrated microsystems. The method in use exemplifies a simple, effective and non-destructive approach for in situ characterization of electro-responsive biopolymers in an aqueous environment.

Graphical abstract: In situ quantitative visualization and characterization of chitosan electrodeposition with paired sidewall electrodes

Supplementary files

Article information

Article type
Paper
Submitted
18 Mar 2010
Accepted
05 May 2010
First published
27 May 2010

Soft Matter, 2010,6, 3177-3183

In situ quantitative visualization and characterization of chitosan electrodeposition with paired sidewall electrodes

Y. Cheng, X. Luo, J. Betz, S. Buckhout-White, O. Bekdash, G. F. Payne, W. E. Bentley and G. W. Rubloff, Soft Matter, 2010, 6, 3177 DOI: 10.1039/C0SM00124D

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