Amyloid fibrils disassembly

This chapter describes the self-assembly of non-native protein fibers known as amyloid fibrils and the development of these fibrils for potential applications in nanotechnology and biomedicine. It extends an earlier review by the author on a related topic (Gras, 2007). In Section 1, the self-assembly of polypeptides into amyloid fibrils and efforts to control assembly and any subsequent disassembly are discussed. In Section 2, this review focuses on the important role of surfaces and interfaces during and after polypeptide assembly. It examines how different surfaces can influence fibril assembly, how surfaces can be used to direct self-assembly in order to create highly ordered structures, and how different techniques can be used to create aligned and patterned materials on surfaces following self-assembly. 

If amyloid fibrils and other self-assembling polypeptide systems are to be developed as new materials and components for nanotechnology and biomedicine, it is important that we understand the pathways and kinetics of their assembly. It will also be desirable to be able to control this assembly and any subsequent disassembly. 

A number of techniques can be used to monitor the growth of amyloid fibrils and provide information on the kinetics of fibril assembly or disassembly. These techniques include light scattering or dye binding assays where Thioflavin T binds to the emerging fibril structure resulting in an increase in fluorescence (Krebs et al., 2005). Fourier transform infrared spectroscopy and circular dichroism can be used to monitor a change in secondary structure as the polypeptide adopts a (3-sheet-rich confirmation (Nilsson, 2004) and a quartz crystal oscillator used to follow an increase in fibril mass as a function of time (Knowles et al., 2007). 

---