초록 |
Many cellular responses, such as adhesion, growth, motility and differentiation as well as apoptosis are surface-mediated. Therefore, the ability to engineer the interactions of cells with surfaces is an extremely important task in medicine and biotechnology. Previous studies in creating cell interactive coating have been focused on only a few materials, yet the practical methodology to create conformal coating over large-area has not been achieved. A promising alternative for assembling soft materials for functional surface coatings is layer-by-layer assembly. Layer-by-layer deposition (LbL) is a versatile technique whereby ultrathin films are assembled from the repetitive, sequential adsorption of oppositely charged polyelectrolytes from dilute aqueous solution. It allows nano-scale control over the thickness, composition, and molecular structure of the deposited multilayer film. Recent development in the multilayer systems using week polyelectrolytes exhibits the unique property, tuning the film properties by changing the pH of the dipping condition. Using murine NR6 fibroblasts, which is well-known “sticky” cell line, cytophilicity or cytophobicity of many multilayer systems was examined. Even when the same polyelectrolytes were used, depending on the pH or ionic strength of the dipping condition, the deposited multilayer films exhibit different cell-adhesiveness. In addition to the electrostatically assembled multilayer systems, the hydrogen-bonded multilayers comprised of polyacrylamide and ether polyacrylic acid or polymethacrylic acid were studied. These hydrogen-bonded films can be selectively stabilized to form micropatterns using inkjet or photo-lithographic methods. The stabilized multilayer films exhibit superb resistance to cell adhesion (fibroblasts, hepatocytes, etc) with long-term durability. The surface of the multilayer film can be functionalized further with specific functional groups such as a cell adhesion peptide ligand. The excellent micropatternability of the films and the tunability of their affinity to cells were combined to study cellular interactions with surfaces. More recently, this H-bonded multilayer was deposited on small colloids (micro- nano-sized) without flocculation, which shows a great potential in selective drug delivery. In addition, the anti-bacterial coating will be also discussed. |