| Abstract
| - We report the layer-by-layer (LbL) preparation of multilayered thin films that consist solely of DNA. The propertiesof the films were varied by assembling the layers from different oligonucleotide building blocks, which are composedof repeating homopolymeric units of nucleotides [adenosine (A), cytosine (C), guanine (G), and thymidine (T)] or“random” sequences. Films assembled from oligonucleotides with a single complementary unit did not show continuallayer buildup. To form a repeating multilayer system, it was necessary for single-stranded DNA to be available forsubsequent layers to hybridize. By using oligonucleotides with multiple nucleotide units, multilayer films were successfullyassembled. We demonstrate that the thickness and swellability of the films can be controlled by the extent of hydrogenbonding (the G/C content of the oligonucleotide) and orientation of the oligomers. We have examined the stabilityand swellability of the films in solutions of varying salt concentration as well as in a denaturing urea solution. Stable,hollow DNA capsules were also formed by preparing the films on sacrificial colloidal templates, followed by removalof the core. The assembly of propagating structures through DNA hybridization paves the way for the engineeringof DNA films with tailored composition, structure, and permeability, making them likely to find application indrug/gene delivery and biomolecular sensing.
|
