De novo design of biomedical polymers: Hybrids from synthetic macromolecules and genetically engineered protein domains

Genetic engineering technology provides a powerful tool for producing tailor-made protein polymers with pre-determined three-dimensional structures because exact control of the primary structure, composition and chain length can be achieved by manipulating the DNA sequence encoding the protein. Two approaches for the de novo design of bio-based systems using the coiled coil protein motif are discussed. One approach was to design hybrid hydrogels from synthetic macromolecules and coiled coil domains as crosslinks. This permits to impose the properties of the protein motif on the properties of the whole hydrogel. Temperature induced phase transition of the coiled coil domain resulted in a collapse of the hydrogel. The second approach was to construct a scaffold for epitope display based on genetically engineered peptides self-assembled on polystyrene surfaces. This construct may serve as a model for biorecognition studies with the aim to identify optimal ligand-receptor pairs. Such information is necessary for a rational design of targeted polymeric drug delivery systems.