Direct Determination of Chitosan–Mucin Interactions Using a Single-Molecule Strategy: Comparison to Alginate–Mucin Interactions

Polymers

Kristin E. Haugstad²  Armend G. Håti²  Catherine T. Nordgård¹  Patricia S. Adl²  Gjertrud Maurstad²  Marit Sletmoen²  Kurt I. Draget¹  Rita S. Dias²  Bjørn T. Stokke² 

[1] Department of Biotechnology, the Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway; E-Mails:;Biophysics and Medical Technology, Department of Physics, the Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway; E-Mails:

关键词: AFM (atomic force microscopy);    mucin;    chitosan;    mucoadhesion;    force spectroscopy;   

DOI  :  10.3390/polym7020161

来源: mdpi

【 摘 要 】

Aqueous chitosan possesses attractive interaction capacities with various molecular groups that can be involved in hydrogen bonds and electrostatic and hydrophobic interactions. In the present paper, we report on the direct determination of chitosan–mucin molecular pair interactions at various solvent conditions as compared to alginate–mucin interactions. Two chitosans of high molecular weight with different degrees of acetylation—thus possessing different solubility profiles in aqueous solution as a function of pH and two alginates with different fractions of α-guluronic acid were employed. The interaction properties were determined through a direct unbinding assay at the single-molecular pair level using an atomic force microscope. When probed against immobilized mucin, both chitosans and alginates revealed unbinding profiles characteristic of localized interactions along the polymers. The interaction capacities and estimated parameters of the energy landscapes of the pairwise chitosan–mucin and alginate–mucin interactions are discussed in view of possible contributions from various fundamental forces. Signatures arising both from an electrostatic mechanism and hydrophobic interaction are identified in the chitosan–mucin interaction properties. The molecular nature of the observed chitosan–mucin and alginate–mucin interactions indicates that force spectroscopy provides fundamental insights that can be useful in understanding the surface binding properties of other potentially mucoadhesive polymers.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.