The objective of this Nanoscale Exploratory Research (NER) interdisciplinary research project is to launch the unlocking of nature's secrets pertaining to self-assembly of large molecules called polypeptides onto an electrically charged surface. The final self-assembled structures are thin films or microcapsules, ranging from a few nanometers to hundreds of nanometers thick. Polypeptides form one of the four major types of biological macromolecule. Modern methods permit synthesis of an effectively unlimited variety of polypeptide structures. The approach of this research encompasses polypeptide synthesis and purification by chemical methods. The polypeptide designs will test key aspects of their physical properties in the self-assembly process. Following purification, polypeptides will be assembled into a thin film, one molecular layer at a time, using a method known as layer-by-layer assembly. The process involves repeated alternation of the net charge of the adsorbing polypeptides, from positive to negative and back again. Film assembly will be monitored, and the resulting films will be characterized using physical techniques. Determining self-assembly properties of polypeptides and properties of the resulting films thus will contribute to basic scientific knowledge.
This research, however, also holds considerable promise for the realization of tangible benefits to human life. Layer-by-layer assembly is generally considered the method of thin film fabrication with the greatest potential for commercialization. At present, though, very little is known about how to optimize the use of polypeptides in this method. Polypeptide thin films are likely to be useful for applications in biotechnology and biomedicine (drug delivery systems), food technology (edible coatings), and homeland defense (anti-microbial coatings).
