Self-assembly of magnetic colloids with shifted dipoles

Soft Matter ◽  
2019 ◽  
Vol 15 (20) ◽  
pp. 4078-4086 ◽  
Author(s):  
Gabriel I. Vega-Bellido ◽  
Ronal A. DeLaCruz-Araujo ◽  
Ilona Kretzschmar ◽  
Ubaldo M. Córdova-Figueroa

The effect of dipolar shift on the size, morphology, and aggregation process of clusters is studied.

Soft Matter ◽  
2020 ◽  
Vol 16 (10) ◽  
pp. 2460-2472
Author(s):  
Jonathan A. Victoria-Camacho ◽  
Ronal A. DeLaCruz-Araujo ◽  
Ilona Kretzschmar ◽  
Ubaldo M. Córdova-Figueroa

The effect of dipolar shift on the rate of aggregation (tz), the aggregation modes and structure of clusters is studied.


2019 ◽  
Author(s):  
Siddhartha Banerjee ◽  
Mohtadin Hashemi ◽  
Karen Zagorski ◽  
Yuri L. Lyubchenko

AbstractThe assembly of polypeptides and proteins into nanoscale aggregates is a phenomenon observed in a vast majority of proteins. Importantly, aggregation of amyloid β (Aβ) proteins is considered as a major cause for the development of Alzheimer’s disease. The process depends on various conditions and typical test-tube experiments require high protein concentration that complicates the translation of results obtained in vitro to understanding the aggregation process in vivo. Here we demonstrate that Aβ42 monomers at the membrane bilayer are capable of self-assembling into aggregates at physiologically low concentrations, and the membrane in this aggregation process plays a role of a catalyst. We applied all-atom molecular dynamics to demonstrate that the interaction with the membrane surface dramatically changes the conformation of Aβ42 protein. As a result, the misfolded Aβ42 rapidly assembles into dimers, trimers and tetramers, so the on-surface aggregation is the mechanism by which amyloid oligomers are produced and spread.


2021 ◽  
Vol 8 ◽  
Author(s):  
Peter Faller ◽  
Christelle Hureau

The self-assembly of peptides and proteins into amyloid fibrils and other aggregates are linked to several diseases. One of the most studied cases is the peptide amyloid-β (Aβ), found self-assembled in Alzheimer's disease patients' brains. In test tubes, assays with chemically synthesized or recombinant Aβ are widely investigated to understand the aggregation process and to find modulators, which could be of therapeutic interest. Experience over more than a decade in our laboratory through discussions with colleagues, expertly studying the literature, and as reviewers revealed to us the widely encountered difficulty to control the aggregation and obtain reproducible results in the test tube. However, this issue is scarcely reported and discussed in the publications, which we think hampers strongly the progress in this field and can deceive newcomers. Here, we describe the difficulty and potential reasons to obtain reproducible aggregation data and propose some guidelines for working with it.


2020 ◽  
Vol 56 (65) ◽  
pp. 9288-9291 ◽  
Author(s):  
Zhenfeng He ◽  
Yufeng Huo ◽  
Chao Wang ◽  
Duo Pan ◽  
Binbin Dong ◽  
...  

The preparation of host imine macrocycles and the self-assembly aggregation process are merged into one single step for self-assembly to form dynamic imine macrocyclic supramolecular polymers.


Small ◽  
2021 ◽  
pp. 2101188
Author(s):  
Fernando Martínez‐Pedrero ◽  
Andrés González‐Banciella ◽  
Alba Camino ◽  
Ana Mateos‐Maroto ◽  
Francisco Ortega ◽  
...  

2012 ◽  
Vol 12 (3) ◽  
pp. 2081-2088 ◽  
Author(s):  
Ye Yang ◽  
Yoshitaka Morimoto ◽  
Tsukasa Takamura ◽  
Adarsh Sandhu

2020 ◽  
Vol 21 (3) ◽  
pp. 1129 ◽  
Author(s):  
Siddhartha Banerjee ◽  
Mohtadin Hashemi ◽  
Karen Zagorski ◽  
Yuri L. Lyubchenko

The self-assembly of amyloid β (Aβ) proteins into oligomers is the major pathogenic event leading to Alzheimer’s disease (AD). Typical in vitro experiments require high protein concentrations, whereas the physiological concentration of Aβ is in the picomolar to low nanomolar range. This complicates the translation of results obtained in vitro to understanding the aggregation process in vivo. Here, we demonstrate that Aβ42 self-assembles into aggregates on membrane bilayers at low nanomolar concentrations - a pathway in which the membrane plays the role of a catalyst. Additionally, physiological ionic conditions (150 mM NaCl) significantly enhance on-membrane aggregation, leading to the rapid formation of oligomers. The self-assembly process is reversible, so assembled aggregates can dissociate from the membrane surface into the bulk solution to further participate in the aggregation process. Molecular dynamics simulations demonstrate that the transient membrane-Aβ interaction dramatically changes the protein conformation, facilitating the assembly of dimers. The results indicate peptide–membrane interaction is the critical step towards oligomer formation at physiologically low protein concentrations.


2016 ◽  
Vol 113 (31) ◽  
pp. 8577-8582 ◽  
Author(s):  
Fabian M. Hecht ◽  
Andreas R. Bausch

The self-organization of colloidal particles is a promising approach to create novel structures and materials, with applications spanning from smart materials to optoelectronics to quantum computation. However, designing and producing mesoscale-sized structures remains a major challenge because at length scales of 10–100 μm equilibration times already become prohibitively long. Here, we extend the principle of rapid diffusion-limited cluster aggregation (DLCA) to a multicomponent system of spherical colloidal particles to enable the rational design and production of finite-sized anisotropic structures on the mesoscale. In stark contrast to equilibrium self-assembly techniques, kinetic traps are not avoided but exploited to control and guide mesoscopic structure formation. To this end the affinities, size, and stoichiometry of up to five different types of DNA-coated microspheres are adjusted to kinetically control a higher-order hierarchical aggregation process in time. We show that the aggregation process can be fully rationalized by considering an extended analytical DLCA model, allowing us to produce mesoscopic structures of up to 26 µm in diameter. This scale-free approach can easily be extended to any multicomponent system that allows for multiple orthogonal interactions, thus yielding a high potential of facilitating novel materials with tailored plasmonic excitation bands, scattering, biochemical, or mechanical behavior.


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