The natural protein synthesis ‘machinery’ in micro-organisms can be used to create novel protein-like polymers that consist of a string of polymer segments (also called ‘modules’ or blocks) with structures inspired by collagen, silk, elastin and other natural fibrous proteins.
The resulting natural polymer molecules can interact with neighbouring molecules and spontaneously give rise to supra-molecular structures such as nano-fibres, nano-coatings, networks/gels, etc.
Because, like proteins, they are made entirely of natural amino acids, and can be fully degraded when needed, they are typically well-tolerated in the body. Yet, their design is determined in the laboratory, and different designs result in specific, but very different behaviour. For example, gel formation, fibre formation, or phase separation can be reversibly steered by changes of temperature, salinity, or acidity (pH), or degradation can be triggered by similar stimuli. In addition, bio-active groups can be built in.
The development of protein polymers is driven by the desire to create specific material properties and functionalities in a rational way, for medical/pharmaceutical and other high-tech applications. The study of the polymers, created by rational design and combination of new and existing ‘modules’, not only generates possibilities for novel practical application, but also provides insight into the relevant structure-function relationships.
Polymers were composed of novel combinations of elastin-, silk- and gelatine-like blocks (modules), which lead to novel polymer behaviour. Based on the same DNA template (synthetic gene), a cell can make thousands of identical copies of exactly the same polymer molecule. High (0.5-15 g/L) product levels were obtained by inserting the gene in Pichia pastoris yeast cells and growing these cells to high cell densities on methanol, a cheap substrate that could in the future be made out of waste biomass. The products were isolated in essentially a single-step precipitation procedure.
The purified products appeared capable of pH- and/or temperature-triggered self-organization into nano-fibres
- Wageningen University – Laboratory (Chair Group) Physical Chemistry & Colloid Science (prof. dr. M. A. Cohen Stuart )
- University of Amsterdam - Van ’t Hoff Institute for Molecular Sciences (prof. dr. P. G. Bolhuis)