Synthesis and Characterization of Molecular Building Blocks for Responsive Materials
Final Report Abstract
Responsive materials can exhibit large changes in their volume and generate force with small environmental changes (e.g. temperature, pH, light or other solution property). These materials have found applications as biomaterials, drug delivery devices, and in microfluidic devices. The most common materials currently used are randomly cross-linked polymer hydrogels. Their major limitation is their ill-defined size, slow response time, poor directionality and the small volume changes. The limitations probably being slow diffusion and aggregation of polymers and water diffusion. The objective of this work was to overcome these limitations by developing molecular scale responsive subunits. They can operate without polymer diffusion and might allow to form dilute gels, which make the polymer and water diffusion not limiting anymore. In a combined effort, together with the group of Prof. Holland (CSU), the molecular building blocks were designed using structures from various natural proteins. From previous studies, trimeric building blocks were thought to be most promising molecular building blocks. In the framework of this project we found that trimeric ELP-based constructs are not responsive by themselves. Fortunately, it turned out that these trimeric constructs form spherical micelles of less than 50nm diameter, which are responsive to temperature changes. This makes them promising candidates for drug delivery and biosensing applications. We have characterized these micelles and have worked towards chemically cross-linked particles, which are stable above and below the micelle formation temperature. Currently, we investigate the uptake and release of dyes, contrast agents and drugs upon changing the temperature for the cross-linked particles. We are convinced, that such particles have a great economic potential in theranostics (combining therapeutic targeted drug delivery with diagnostic imaging contrast agent).
Publications
- ChemPhysChem, 13, 982 (2012) “The effect of temperature on single polypeptide adsorption”
S. Kienle, S. Liese, N. Schwierz, R.R. Netz, T.Hugel
(See online at https://doi.org/10.1002/cphc.201100776) - Faraday Disc, 160, 329 (2013) “Measuring the interaction between ions, biopolymers and interfaces – one polymer at a time”
S. Kienle, T. Pirzer, S. Krysiak, M. Geisler, T.Hugel
(See online at https://doi.org/10.1039/c2fd20069d)
