An In Situ Study of Collagen Self-Assembly Processes

Köster, Sarah; Evans, Heather M.; Wong, Joyce Y.; Pfohl, Thomas

doi:10.1021/bm700973t

Cited by 63 publications

(53 citation statements)

References 37 publications

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“…In the liquid dispersion, fibrils are fairly free to rotate (a), thanks to strong electrostatic repulsion (e). An accelerating flow causes the fibrils to align in the flow direction202128 (b). Before the alignment is lost due to Brownian diffusion (c), the electrostatic repulsion between the particles is reduced by an electrolyte diffusing into the suspension (f–h).…”

Section: Resultsmentioning

confidence: 99%

Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments

et al. 2014

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Cellulose nanofibrils can be obtained from trees and have considerable potential as a building block for biobased materials. In order to achieve good properties of these materials, the nanostructure must be controlled. Here we present a process combining hydrodynamic alignment with a dispersion–gel transition that produces homogeneous and smooth filaments from a low-concentration dispersion of cellulose nanofibrils in water. The preferential fibril orientation along the filament direction can be controlled by the process parameters. The specific ultimate strength is considerably higher than previously reported filaments made of cellulose nanofibrils. The strength is even in line with the strongest cellulose pulp fibres extracted from wood with the same degree of fibril alignment. Successful nanoscale alignment before gelation demands a proper separation of the timescales involved. Somewhat surprisingly, the device must not be too small if this is to be achieved.

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Section: Resultsmentioning

confidence: 99%

Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments

et al. 2014

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“…4 A number of papers on the effects of solvent conditions such as concentration, temperature and ionic strength on the final morphology of the products and an exhaustive description of the process have appeared in the literature. 5,6 Studies on the self-assembly and dynamic evolution of collagen gels from semidilute solutions in a microfluidic device have been reported recently by Köster et al 7 A number of unanswered questions concerning folding and other changes in secondary structures of proteins forming stable aggregate structures still exist. 8 The exact contributions from electrostatic, dispersive and H-bonding forces are also not completely understood.…”

Section: Introductionmentioning

confidence: 99%

Directed 2-dimensional organisation of collagen: Role of cross-linking and denaturing agents

Fathima

Dhathathreyan

Ramasami³

2010

J Chem Sci

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The effect of additives like curcumin and surfactants on the self-assembly of collagen from a simple 2-dimensional system of Langmuir films of the protein at air/solution interface has been attempted in this study using quartz crystal microbalance (QCM) and dynamic surface tensiometer. Though pure curcumin is not surface active, a synergistic effect of collagen with curcumin seems to lead to enhanced surface activity in the protein. In general, the presence of additives, increases the surface activity of collagen even for the lowest concentration and the largest change in surface activity is seen for collagen with sodium dodecyl sulfate (SDS). The results suggest interplay between the unexposed hydrophobic groups, and the opening out and solvation of the more charged or polar groups at the surface leading to aggregation followed by self-assembly. Modulation of aggregation at interface in collagen due to these additives may be an approach that could be explored for possible applications in bio-materials and for delivery of protein-drug complexes.

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“…The phase behavior of PNFs in relation to physiochemical parameters (e.g., pH, protein concentration, and ionic strength) has been studied in bulk solution (11), providing some understanding of their microscale assembly mechanisms. However, forced extension toward alignment of fibrils is a common component of wet spinning techniques, which have emerged as promising procedures for controlled fiber formation (12)(13)(14)(15)(16)(17)(18). We here make use of recent insights into the behavior of nanofibrils under elongational flow and the developments in X-ray transparent small-scale flow devices and high-brilliance microfocused X-ray beams (13,17,19) to carry out in situ investigations of the assembly of PNFs during the flow orientation.…”

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confidence: 99%

Flow-assisted assembly of nanostructured protein microfibers

Kamada

Mittal

Söderberg

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

115

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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.protein nanofibrils | amyloid | hierarchical assembly | flow focusing | small-angle X-ray scattering P roteins are widely used in nature to create high-performance materials that can have both extraordinary mechanical properties (similar to muscles, silks) and sophisticated functionalities (e.g., adhesion, biological signaling) (1). The characteristics of these materials are intimately connected to the hierarchical assembly of the protein building blocks with well-defined organization at all structural levels (2). Improved knowledge about how to control the assembly of protein molecules into higher-order structures would open the possibilities to create novel bio-based materials for a variety of applications. In this perspective, the ability of protein molecules to undergo nonnative self-assembly into protein nanofibrils (PNFs) with highly organized supramolecular structures is of significant interest (3). The formation of PNFs was initially observed in association with diseases, such as Alzheimer's and Parkinson's diseases, and type II diabetes, where human organs are impaired by fibrous protein inclusions referred to as amyloid (4). However, several non-disease-related proteins have also been shown to form amyloid-like fibrils, e.g., the bovine whey protein β-lactoglobulin (5), hen-egg lysozyme (6), and soybean proteins (7). The unique fibrous structures of PNFs have the potential for being the building block of protein-based nanomaterials and to be used as scaffolds for applications such as tissue engineering, drug delivery systems, and biosensors (3). PNFs are characterized by intermolecular β-sheet structures, where the peptide backbones are oriented perpendicularly to the fibril axis and connected through a network of hydrogen bonds (4,8). This provides them with stiffness equivalent to silk and strength comparable to steel (2, 8). Moreo...

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An In Situ Study of Collagen Self-Assembly Processes

Cited by 63 publications

References 37 publications

Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments

Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments

Directed 2-dimensional organisation of collagen: Role of cross-linking and denaturing agents

Flow-assisted assembly of nanostructured protein microfibers

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