A droplet reactor on a super-hydrophobic surface allows control and characterization of amyloid fibril growth.

Zhang, Peng; Moretti, Manola; Allione, Marco; Tian, Yuansi; Ordonez-Loza, Javier; Altamura, Davide; Giannini, Cinzia; Torre, Bruno; Das, Gobind; Li, Erqiang; Thoroddsen, Sigurdur T.; Sarathy, S. Mani; Autiero, Ida; Giugni, Andrea; Gentile, Francesco; Malara, Natalia; Marini, Monica; Di Fabrizio, Enzo

Methods to produce protein amyloid fibrils, in vitro, and in situ structure characterization, are of primary importance in biology, medicine, and pharmacology. We first demonstrated the droplet on a super-hydrophobic substrate as the reactor to produce protein amyloid fibrils with real-time monitoring of the growth process by using combined light-sheet microscopy and thermal imaging. The molecular structures were characterized by Raman spectroscopy, X-ray diffraction and X-ray scattering. We demonstrated that the convective flow induced by the temperature gradient of the sample is the main driving force in the growth of well-ordered protein fibrils. Particular attention was devoted to PHF6 peptide and full-length Tau441 protein to form amyloid fibrils. By a combined experimental with the molecular dynamics simulations, the conformational polymorphism of these amyloid fibrils were characterized. The study provided a feasible procedure to optimize the amyloid fibrils formation and characterizations of other types of proteins in future studies. Zhang et al present an integrated real-time imaging and flow field control platform based on water droplet evaporation on super-hydrophobic substrate (SHS) to enable amyloid fibril aggregation. They apply this methodology to observe structural polymorphism in PHF6 peptide and full length Tau441.

HYDROPHOBIC surfaces; AMYLOID; GENETIC polymorphisms; X-ray scattering; RAMAN spectroscopy

Communications Biology, 2020, Vol 3, Issue 1, pN.PAG

2399-3642

Academic Journal

10.1038/s42003-020-01187-7