| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014) | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI-WeM |
| Session: | Biomaterials, Interfaces, and Cells |
| Presenter: | Cathy McNamee, Shinshu University, Japan |
| Authors: | C. McNamee, Shinshu University, Japan Y. Taira, Tohoku University, Japan |
| Correspondent: | Click to Email |
Chitin and chitosan show biocompatibility, biodegradability, and non-toxity, and are therefore used in pharmaceutical and biomedical applications. The successful applications of chitin and chitosan require the ability to create well-defined films that display the required properties in the working environment. This ability requires an in-depth understanding on the physical properties of the films created using chitin or chitosan and the way to control these properties in different environments. The polysaccharide type, its conformation and packing in the film, and the surrounding liquids in the working environment contribute to the forces and friction of the system, which affect the properties of the polysaccharide films. We investigated the effect of the polysaccharide type, the subphase on which the chitin or chitosan Langmuir monolayers were prepared, and the liquid in which the properties of the transferred monolayers were measured on the physical properties of the polysaccharide films at an air/aqueous interface and at a liquid/silicon substrate interface, and the forces and friction of the polysaccharide transferred films when measured in solution against a silica probe.
Chitosan was modified with a silane coupling agent to make chitosan derived compounds with a low and a medium molecular weight. Chitin and the chitosan-derived compounds were used to make Langmuir monolayers at air/water and air/pH 9 buffer interfaces. The monolayers were transferred to silicon substrates via a Langmuir-Blodgett deposition, and the chitosan-derived compounds subsequently chemically reacted to the silicon substrates. Atomic Force Microscope force and friction measurements were made in water and in the pH 9 buffer, where the water and the pH 9 buffer acted as a good and a bad solvent to the polysaccharides, respectively.
The polysaccharide type affected the friction of the polysaccharide film, where the physically adsorbed chitin gave the lowest friction. The forces and friction of the polysaccharide films changed when the subphase on which the Langmuir monolayers were formed was changed or when the liquid in which the properties of the films adsorbed at the silicon substrate were being measured was changed. The friction increased significantly when the liquid was changed from water to the pH 9 buffer.