RUI: Investigations of hydrogels formed by semenogelin I-derived peptide sequences

Haverford College, Haverford PA

Investigators

Abstract

Hydrogels are materials with a tremendous capacity to absorb water, which makes them useful for a variety of every-day applications such as baby diapers, contact lenses and drug encapsulation. Hydrogels consist of polymer networks and new types of hydrogel polymers are continuously being developed. There is a considerable interest in learning what the detailed structure of a hydrogel looks like and how the structure of the network influences the hydrogel properties as well as how the hydrogel polymers can be modified at will. The aim of this research is to investigate the formation of a hydrogel from natural proteins. This hydrogel, because it is of natural origin, is non-toxic, biocompatible, biodegradable and environmentally friendly. This research involves an international collaboration between research groups at Haverford College, US; Lund University, Sweden; and the University of Cambridge, UK. The project provides interdisciplinary and international research opportunities to undergraduate students. The project also includes participation by students from underrepresented groups, preparing them for graduate studies in a variety of chemically related fields, as well as for careers in industry. The undergraduate participants of this project gain direct hands-on experience and training in state-of-the-art methodologies for solid-phase protein synthesis and purification. This research aims to understand gel formation by peptide scaffolds. The oligopeptide under investigation self-assembles to form fibrils consisting of extended beta-sheets. This short 10-residue peptide forms a hydrogel with properties that are particularly well suited for systematic investigations. This project probes the sequence-specific determinants of hydrogel formation by studying a series of mutants and truncated versions of the oligopeptide, employing predominantly circular dichroism and Fourier transform infrared spectroscopy for their characterization The research interrogates the self-assembly process by incorporating isotopically labeled residues into the sequence. Finally, the researchers follow the kinetics of fibril formation using a thioflavine-based assay, which is also used as a tool to assess the effects of external variables, such as pH, on aggregation.