Controlling amyloid fibril formation by partial stirring

Bäcklund, Fredrik; Pallbo, Jon; Solin, Niclas

doi:10.1002/bip.22803

Cited by 17 publications

(16 citation statements)

References 52 publications

(113 reference statements)

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“…Previous research has demonstrated that the properties of proteins can be modified with various pH, temperatures, by stirring during different phases of fibrillization process and by doping them with different nanoparticles . For instances, copolymer particles, cerium oxide particles, carbon nanotubes, and quantum dots have been confirmed with their ability to enhance the rate of fibril formation .…”

Section: Introductionmentioning

confidence: 99%

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Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites

et al. 2019

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We present colloidal nanocomposites formed by incorporating magnetite Fe3O4 nanoparticles (MNPs) with lysozyme amyloid fibrils (LAFs). Preparation of two types of solutions, with and without addition of salt, was carried out to elucidate the structure of MNPs‐incorporated fibrillary nanocomposites and to study the effect of the presence of salt on the stability of the nanocomposites. The structural morphology of the LAFs and their interaction with MNPs were analyzed by atomic force microscopy and small‐angle x‐ray scattering measurements. The results indicate that conformational properties of the fibrils are dependent on the concentration of protein, and the precise ratio of the concentration of the protein and MNPs is crucially important for the stability of the fibrillary nanocomposites. Our results confirm that despite the change in fibrillary morphology induced by the varying concentration of the protein, the adsorption of MNPs on the surface of LAF is morphologically independent. Moreover, most importantly, the samples containing salt have excellent stability for up to 1 year of shelf‐life.

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Section: Introductionmentioning

confidence: 99%

“…different nanoparticles. [15][16][17][18] For instances, copolymer particles, cerium oxide particles, carbon nanotubes, and quantum dots have been confirmed with their ability to enhance the rate of fibril formation. [13] Xu et al…”

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confidence: 99%

Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites

et al. 2019

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“…Standard approaches to functionalize such structures would be to attach hydrophilic moieties to the hydrophobic dye; conjugate the hydrophobic dye to the protein, or in the case of relatively polar hydrophobic dyes employ an organic co-solvent miscible with water. We recently reported a novel method for protein functionalization utilizing a preliminary mechanochemical mixing step [31][32][33][34][35][36]. By co-grinding the hydrophobic dye and the protein, a composite material is formed that can be dissolved in water.…”

Section: Introductionmentioning

confidence: 99%

“…Impact forces should lead to division of dye particles but is expected to be less efficient than shear at tearing of thin layers of dye molecules. With the above point in mind, grinding with mortar and pestle should be an efficient technique for dispersing dyes in a protein matrix, and we have utilized this method in several publications, where the protein bovine insulin has been mixed with a variety of hydrophobic dyes/materials [31][32][33][34][35][36]. However, mechanochemistry by hand grinding with mortar and pestle suffers from some drawbacks.…”

Section: Introductionmentioning

confidence: 99%

Preparation of functionalized protein materials assisted by mechanochemistry

Wang

Solin

2018

J Mater Sci

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Herein, we investigate the suitability of hen egg-white lysozyme (HEWL) as a protein matrix for dispersal of various hydrophobic dyes. Moreover, we investigate the use of a mixer mill for grinding operation as an alternative to hand grinding by mortar and pestle. HEWL and various dyes are mixed by mechanochemistry, and the resulting composite material is dissolved in aqueous acid. The samples are then exposed to conditions promoting self-assembly of HEWL into protein nanofibrils (PNFs). The effect of PNF formation on dye photophysics is investigated by spectroscopic examination by absorption and luminescence spectroscopy, and product morphology is examined by scanning electron microscopy. The self-assembly process results in protein nanofibrils functionalized with luminescent dyes. Such structures may find future applications in various devices for light emission. In addition, we demonstrate that the anticancer drug camptothecin can be incorporated into protein nanofibrils giving materials that can find application as drug delivery agents.

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“…The assembly process depends on several factors, such as the protein concentration, temperature, pH and ion concentrations, and has been described elsewhere. [43][44][45][46][47][48][49][50][51] The microscopy efforts in this work focused on spherulites prepared from these proteins and the intrinsic optical properties of these amyloid structures were utilized in label-free imaging applications.…”

Section: Introductionmentioning

confidence: 99%

Label-free imaging of amyloids using their intrinsic linear and nonlinear optical properties

Johansson¹,

Koelsch²

2017

Biomed. Opt. Express

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The optical properties of amyloid fibers are often distinct from those of the source protein in its non-fibrillar form. These differences can be utilized for label-free imaging or characterization of such structures, which is particularly important for understanding amyloid fiber related diseases such as Alzheimer's and Parkinson's disease. We demonstrate that two amyloid forming proteins, insulin and β-lactoglobulin (β-LG), show intrinsic fluorescence with emission spectra that are dependent on the excitation wavelength. Additionally, a new fluorescence peak at about 430 nm emerges for β-LG in its amyloid state. The shift in emission wavelength is related to the red edge excitation shift (REES), whereas the additional fluorescence peak is likely associated with charge delocalization along the fiber backbone. Furthermore, the spherulitic amyloid plaque-like superstructures formed from the respective proteins were imaged label-free with confocal fluorescence, multiphoton excitation fluorescence (MPEF), and second-harmonic generation (SHG) microscopy. The latter two techniques in particular yield images with a high contrast between the amyloid fiber regions and the core of amorphously structured protein. Strong multiphoton absorption (MPA) for the amyloid fibers is a likely contributor to the observed contrast in the MPEF images. The crystalline fibrillar region provides even higher contrast in the SHG images, due to the inherently ordered non-centrosymmetric structure of the fibers together with their non-isotropic arrangement. Finally, we show that MPEF from the insulin spherulites exhibits a spectral dependence on the excitation wavelength. This behavior is consistent with the REES phenomenon, which we hypothesize is the origin of this observation. The presented results suggest that amyloid deposits can be identified and structurally characterized based on their intrinsic optical properties, which is important for probe-less and label-free identification and characterization of amyloid fibers in vitro and in complex biological samples. A. 82(12), 4245-4249 (1985). 8. L. C. Serpell, "Alzheimer's amyloid fibrils: structure and assembly," Biochim. Biophys. Acta 1502(1), 16-30 (2000

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Controlling amyloid fibril formation by partial stirring

Cited by 17 publications

References 52 publications

Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites

Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites

Preparation of functionalized protein materials assisted by mechanochemistry

Label-free imaging of amyloids using their intrinsic linear and nonlinear optical properties

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