Abstracts

Proteins are natural polypeptidesproduced by cells; they can be found in both animals and plants,and possess a variety of functions. One of these functions is toprovide structural support to the surrounding cells and tissues.For example, collagen (which is found in skin, cartilage, tendonsand bones) and keratin (which is found in hair and nails) arestructural proteins. When a tissue is damaged, however, thesupporting matrix formed by structural proteins cannot alwaysspontaneously regenerate. Tailor-made synthetic polypeptides can beused to help heal and restore tissue formation. Syntheticpolypeptides are typically synthesized by the so-called ringopening polymerization (ROP) of -amino acid N-carboxyanhydrides(NCA). Such synthetic polypeptides are generallynon-sequence-controlled and thus less complex than proteins. Assuch, synthetic polypeptides are rarely as efficient as proteins intheir ability to self-assemble and form hierarchical or structuralsupramolecular assemblies in water, and thus, often requirerational designing. In this doctoral work, two types of aminoacids, -benzyl-L/D-glutamate (BLG / BDG) and allylglycine (AG),were selected to synthesize a series of (co)polypeptides ofdifferent compositions and molar masses. A new and versatilesynthetic route to prepare polypeptides was developed, and itsmechanism and kinetics were investigated. The polypeptideproperties were thoroughly studied and new materials were developedfrom them. In particular, these polypeptides were able to aggregate(or self-assemble) in solution into microscopic fibres, verysimilar to those formed by collagen. By doing so, they formedrobust physical networks and organogels which could be processedinto high water-content, pH-responsive hydrogels. Particles withhighly regular and chiral spiral morphologies were also obtained byemulsifying these polypeptides. Such polypeptides and the materialsderived from them are, therefore, promising candidates forbiomedical applications. Proteine, auch Polypeptide genannt,sind groe Biomolekle, die aus kleineren Aminosuren bestehen.Diese sind zu langen Ketten miteinander verbunden, wie die Perlenauf einer Perlenkette. Sie werden in Zellen produziert, knnen inTieren und Pflanzen gefunden werden und haben vielfltigeFunktionen. Eine dieser Funktionen ist es, die umgebenen Zellen undGewebe wie ein Gerst zu sttzen. Kollagen (welches in Haut,Knorpel, Sehnen und Knochen zu finden ist) und Keratin (welches inHaaren und Ngeln vorkommt) gehren zu diesen Strukturproteinen.Jedoch wenn ein Gewebe beschdigt ist, beispielsweise als Folgeeines Unfalls, kann sich das Grundgerst aus diesenStrukturproteinen manchmal nicht mehr selbst regenerieren.Magefertigte synthetische Polypeptide, knnen dafr verwendetwerden, die Heilung und Wiederherstellung des Gewebes zuUntersttzen. Diese Polypeptide werden mit einer Reihe anchemischen Reaktionen synthetisiert, welche hauptschlich daraufabzielen Aminosuren miteinander zu verknpfen. SynthetischePolypeptide sindAdvisors/Committee Members: Schlaad, Helmut (advisor).