Abstract
The rheological characteristics of pre-spun native silk protein, which is stored as a viscous pulp inside the silk gland, are the key factors that determine the mechanical performance of the endpoint material: the spun silk fibers. In silkworms and arthropods, microcompartmentalization was shown to play an important regulatory role in storing and stabilizing the aggregation-prone silk and in initiating the fibrillar self-assembly process. However, our current understanding of the mechanism of stabilization of the highly unstable protein pulp in its soluble state inside the microcompartments and of the conditions required for initiating the structural transition in protein inside the microcompartments remains limited. Here, we exploited the power of droplet microfluidics to mimic the silk protein’s microcompartmentalization event; we introduced changes in the chemical environment and analyzed the storage-to-spinning transition as well as the accompanying structural changes in silk fibroin protein, from its native fold into an aggregative β-sheet-rich structure. Through a combination of experimental and computational simulations, we established the conditions under which the structural transition in microcompartmentalized silk protein is initiated, which, in turn, is reflected in changes in the silk-rich fluid behavior. Overall, our study sheds light on the role of the independent parameters of a dynamically changing chemical environment, changes in fluid viscosity, and the shear forces that act to balance silk protein self-assembly, and thus, facilitate new exploratory avenues in the field of biomaterials.
Original language | English |
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Pages (from-to) | 8984-8995 |
Number of pages | 12 |
Journal | Langmuir |
Volume | 39 |
Issue number | 26 |
DOIs | |
State | Published - 4 Jul 2023 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2023 American Chemical Society.
Funding
U.S. acknowledges financial support from the Gruber Foundation, Nella and Leon Benoziyo Center for Neurological Diseases. M.E.M. thanks Sergio Lombroso Fellowship (for Cancer Research) for financial support. In addition, U.S. thanks the Perlman family for funding the Shimanovich Lab at the Weizmann Institute of Science: “This research was made possible in part by the generosity of the Harold Perlman Family.” The authors would like to acknowledge partial support from the GMJ Schmidt Minerva Center of Supramolecular Architectures at the Weizmann Institute, Mondry Family Fund for University of Michigan/Weizmann collaboration, Gerald Schwartz and Heather Reisman Foundation, and WIS Sustainability and Energy Research Initiative (SAERI). This research was supported by a research grant from the Tom and Mary Beck Center for Advanced and Intelligent Materials at the Weizmann Institute of Science, Rehovot, Israel. The authors would like to acknowledge the Scanning Electron Microscopy Unit at the Weizmann Institute of Science. The authors thank Steve Manch for editing English in the manuscript. The authors also thank Prof. Hanna Rapaport and Dr. Elad Arad from the Ben-Gurion University of the Negev (Israel) for their assistance in CD analysis.
Funders | Funder number |
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Gerald Schwartz and Heather Reisman Foundation | |
Mondry Family Fund for University of Michigan/Weizmann | |
Perlman family for funding the Shimanovich Lab | |
SAERI | |
Tom and Mary Beck Center for Advanced and Intelligent Materials at the Weizmann Institute of Science, Rehovot, Israel | |
WIS Sustainability and Energy Research Initiative | |
Weizmann Institute | |
Gruber Foundation | |
Cancer Research UK | |
Weizmann Institute of Science | |
Ben-Gurion University of the Negev |