作者： Marta Owczarza, Sreenath Bolisettyb, Raffaele Mezzengab, Paolo Arosioa

a Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland

b Institute of Food, Nutrition and Health, Food and Soft Materials Science, ETH Zurich, Switzerland

 

摘要：We characterized the sol–gel transition of positively charged fibrils composed of the model amphiphilic peptide RADARADARADARADA (RADA 16-I) using a combination of microscopy, light scattering, microrheology and rheology techniques, and we investigated the dependence of the hydrogel formation on fibril concentration and ionic strength. The peptide is initially present as a dispersion of short rigid fibrils with average length of about 100 nm. During incubation, the fibrils aggregate irreversibly into longer fibrils and fibrillar aggregates. At peptide concentrations in the range 3–6.5 g/L, the fibrillar aggregates form a weak gel network which can be destroyed upon dilution. Percolation occurs without the formation of a nematic phase at a critical peptide concentration which decreases with increasing ionic strength. The gel structure can be well described in the frame of the fractal gel theory considering the network as a collection of fibrillar aggregates characterized by self-similar structure with a fractal dimension of 1.34.

 

關鍵詞：Peptide self-assembly; Fibrillar hydrogel; Aggregation; Gelation; Fractal gel model