title: Flow-assisted assembly of nanostructured protein microfibers.
abstract: Some of the most remarkable materials in nature are made from proteins. The properties of these materials are closely connected to the hierarchical assembly of the protein building blocks. In this perspective, amyloid-like protein nanofibrils (PNFs) have emerged as a promising foundation for the synthesis of novel bio-based materials for a variety of applications. Whereas recent advances have revealed the molecular structure of PNFs, the mechanisms associated with fibril-fibril interactions and their assembly into macroscale structures remain largely unexplored. Here, we show that whey PNFs can be assembled into microfibers using a flow-focusing approach and without the addition of plasticizers or cross-linkers. Microfocus small-angle X-ray scattering allows us to monitor the fibril orientation in the microchannel and compare the assembly processes of PNFs of distinct morphologies. We find that the strongest fiber is obtained with a sufficient balance between ordered nanostructure and fibril entanglement. The results provide insights in the behavior of protein nanostructures under laminar flow conditions and their assembly mechanism into hierarchical macroscopic structures.
authors.affiliation: Linné FLOW Centre, Department of Mechanics, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Kamada
authors.affiliation: Linné FLOW Centre, Department of Mechanics, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.|Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Nitesh
authors.initials: N
authors.lastname: Mittal
authors.affiliation: Linné FLOW Centre, Department of Mechanics, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.|Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: L Daniel
authors.initials: LD
authors.lastname: Söderberg
authors.affiliation: Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.|Division of Coating Technology, Department of Fiber and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Tobias
authors.initials: T
authors.lastname: Ingverud
authors.affiliation: Photon Science, Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg, Germany.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Ohm
authors.affiliation: Division of Coating Technology, Department of Fiber and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.|Photon Science, Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg, Germany.
authors.forename: Stephan V
authors.initials: SV
authors.lastname: Roth
authors.affiliation: Linné FLOW Centre, Department of Mechanics, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden; fredrik@mech.kth.se lendel@kth.se.|Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Lundell
authors.affiliation: Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden fredrik@mech.kth.se lendel@kth.se.
authors.forename: Christofer
authors.initials: C
authors.lastname: Lendel
mesh_terms: D007782:Lactoglobulins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry*; D012212:Rheology; D053838:Scattering, Small Angle
chemical_list: D007782:Lactoglobulins
keywords: amyloid; flow focusing; hierarchical assembly; protein nanofibrils; small-angle X-ray scattering