0000000000749208
AUTHOR
Jong-dal Hong
Layer-by-layer deposited multilayer assemblies of polyelectrolytes and proteins: from ultrathin films to protein arrays
We have recently introduced a new method of creating ultrathin films of polyelectrolytes based on the electrostatic attraction between opposite charges. Multilayer assemblies are adsorbed in a layer-by-layer fashion from aqueous solutions of the polymers. The total film thickness can easily be adjusted by varying the ionic strength of the solution. Here, we report on the temperature stability and the water content of the multilayer assemblies. Furthermore, we have extended our concept to the incorporation of protein layers into films of synthetic polyelectrolytes. The well established system biotin/streptavidin was used to construct such multilayers, also by biospecific recognition. Adsorpt…
Buildup of ultrathin multilayer films by a self-assembly process: III. Consecutively alternating adsorption of anionic and cationic polyelectrolytes on charged surfaces
A solid substrate with a positively charged planar surface is immersed in a solution containing an anionic polyelectrolyte and a monolayer of the polyanion is adsorbed. Since the adsorption is carried out at relatively high concentrations of polyelectrolyte, a large number of ionic residues remain exposed to the interface with the solution and thus the surface charge is effectively reversed. After rinsing in pure water the substrate is immersed in the solution containing a cationic polyelectrolyte. Again a monolayer is adsorbed but now the original surface charge is restored. By repeating both steps in a cyclic fashion, alternating multilayer assemblies of both polymers are obtained. The bu…
Layer-by-Layer Adsorption: The Solid/Liquid-Interface as a Template for the Controlled Growth of Well-Defined Nanostructures of Polyelectrolytes, Proteins, DNA and Polynucleotides
This report describes the construction of ultrathin films whose structure can be tailored on the molecular scale. The resulting supramolecular film architectures may include functional biological macromolecules such as proteins or polynucleotides. The average distances of two functional layers can be adjusted on the nanometer scale (from less than lnm to several tens of nanometers), with a precision of approximately 0.1 nm. This control is achieved by varying the number and the thickness of the polyelectrolyte interlayers and requires the capability of steering each adsorption step with high accuracy. A crucial factor is the fabrication and manipulation of the film surface at each adsorptio…