Spatiotemporal Formation Kinetics of Polyelectrolyte Complex Micelles with Millisecond Resolution

We have directly observed the in situ self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. A synthesized neutral-charged diblock polycation and homopolyanion that we have previously investigated as a model charge-matched, core-shell micelle system were selected for this work. The initial micellization of the oppositely charged polyelectrolytes was completed within the dead time of mixing of 100 ms, followed by micelle growth and equilibration up to several seconds. By combining the structural evolution of the radius of gyration (Rg) and aggregation number (N) with complementary molecular dynamics simulations, we develop new information on how the self-assemblies evolve incrementally in size over time through a two-step kinetic process: first, oppositely-charged polyelectrolyte chains pair to form nascent aggregates that immediately assemble into spherical micelles, and second, these PEC micelles grow into larger micellar entities. This work has determined one possible kinetic pathway for the initial formation of PEC micelles, which provides useful physical insights for increasing fundamental understanding self-assembly dynamics driven by polyelectrolyte complexation that occur on ultrafast timescales.

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In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

10.26434/chemrxiv.9876395.v1 ◽

2019 ◽

Author(s):

Hao Wu ◽

Jeffrey Ting ◽

Siqi Meng ◽

Matthew Tirrell

Keyword(s):

Small Angle ◽

Self Assembly ◽

Electrostatic Interactions ◽

Polyelectrolyte Complex ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

Kinetics Of ◽

Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

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Dissecting the self-assembly kinetics of multimeric pore-forming toxins

Journal of The Royal Society Interface ◽

10.1098/rsif.2015.0762 ◽

2016 ◽

Vol 13 (114) ◽

pp. 20150762 ◽

Cited By ~ 7

Author(s):

A. A. Lee ◽

M. J. Senior ◽

M. I. Wallace ◽

T. E. Woolley ◽

I. M. Griffiths

Keyword(s):

Single Molecule ◽

Self Assembly ◽

Quantitative Agreement ◽

Time Resolved ◽

Biologically Relevant ◽

Low Concentrations ◽

Assembly Kinetics ◽

Quantitative Understanding ◽

Mechanism And Kinetics ◽

Kinetics Of

Pore-forming toxins are ubiquitous cytotoxins that are exploited by both bacteria and the immune response of eukaryotes. These toxins kill cells by assembling large multimeric pores on the cell membrane. However, a quantitative understanding of the mechanism and kinetics of this self-assembly process is lacking. We propose an analytically solvable kinetic model for stepwise, reversible oligomerization. In biologically relevant limits, we obtain simple algebraic expressions for the rate of pore formation, as well as for the concentration of pores as a function of time. Quantitative agreement is obtained between our model and time-resolved kinetic experiments of Bacillus thuringiensis Cry1Ac (tetrameric pore), aerolysin, Staphylococcus aureus α -haemolysin (heptameric pores) and Escherichia coli cytolysin A (dodecameric pore). Furthermore, our model explains how rapid self-assembly can take place with low concentrations of oligomeric intermediates, as observed in recent single-molecule fluorescence experiments of α-haemolysin self-assembly. We propose that suppressing the concentration of oligomeric intermediates may be the key to reliable, error-free, self-assembly of pores.

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Microfluidics for Time-Resolved Small-Angle X-Ray Scattering

10.5772/intechopen.95059 ◽

2020 ◽

Author(s):

Susanne Seibt ◽

Timothy Ryan

Keyword(s):

Self Assembly ◽

Structural Evolution ◽

Time Resolved ◽

X Ray ◽

Structural Characterisation ◽

X Ray Scattering ◽

Saxs Analysis ◽

Kinetics Of ◽

Ray Scattering

With the advent of new in situ structural characterisation techniques including X-ray scattering, there has been an increased interest in investigations of the reaction kinetics of nucleation and growth of nanoparticles as well as self-assembly processes. In this chapter, we discuss the applications of microfluidic devices specifically developed for the investigation of time resolved analysis of growth kinetics and structural evolution of nanoparticles and nanofibers. We focus on the design considerations required for spectrometry and SAXS analysis, the advantages of using a combination of SAXS and microfluidics for these measurements, and discuss in an applied fashion the use of these devices for time-resolved research.

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Fast Self-Assembly Kinetics of Quantum Dots and a Dendrimeric Peptide Ligand

Langmuir ◽

10.1021/la301227r ◽

2012 ◽

Vol 28 (21) ◽

pp. 7962-7966 ◽

Cited By ~ 39

Author(s):

Jianhao Wang ◽

Pengju Jiang ◽

Zuoyan Han ◽

Lin Qiu ◽

Cheli Wang ◽

...

Keyword(s):

Quantum Dots ◽

Self Assembly ◽

Peptide Ligand ◽

Assembly Kinetics ◽

Kinetics Of

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The role of sucrose concentration in self-assembly kinetics of high methoxyl pectin

International Journal of Biological Macromolecules ◽

10.1016/j.ijbiomac.2018.02.103 ◽

2018 ◽

Vol 112 ◽

pp. 1183-1190 ◽

Cited By ~ 14

Author(s):

Daniela Giacomazza ◽

Donatella Bulone ◽

Pier Luigi San Biagio ◽

Rosamaria Marino ◽

Romano Lapasin

Keyword(s):

Self Assembly ◽

Sucrose Concentration ◽

Assembly Kinetics ◽

Kinetics Of

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Self-Assembly Kinetics of Amphiphilic Dendritic Copolymers

Macromolecules ◽

10.1021/acs.macromol.6b02331 ◽

2017 ◽

Vol 50 (4) ◽

pp. 1657-1665 ◽

Cited By ~ 5

Author(s):

Cuiyun Zhang ◽

You Fan ◽

Yunyi Zhang ◽

Cong Yu ◽

Hongfei Li ◽

...

Keyword(s):

Self Assembly ◽

Assembly Kinetics ◽

Kinetics Of

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Dissolution Dynamics of Sub-Critical Clusters in Liquid Silicon

MRS Proceedings ◽

10.1557/proc-205-417 ◽

1990 ◽

Vol 205 ◽

Cited By ~ 5

Author(s):

Michael J. Uttormark ◽

Stephen J. Cook ◽

Michael O. Thompson ◽

Paulette Clancy

Keyword(s):

Molecular Dynamics ◽

System Size ◽

Atomic Processes ◽

Spontaneous Nucleation ◽

New Information ◽

Different Temperatures ◽

Transient Nucleation ◽

Dynamics Simulations ◽

Small Clusters ◽

Kinetics Of

AbstractPrevious attempts to simulate by Molecular Dynamics the spontaneous nucleation and growth of a crystalline Stillinger-Weber ‘silicon’ from the liquid have been essentially impossible because of constraints on system size and time scales. We have overcome these limitations by studying the related problem of the disintegration of crystalline ‘embryos’ into the liquid phase at temperatures slightly above the melting point. Molecular Dynamics simulations using the Stillinger-Weber potential were performed by embedding crystallites of 400 atoms in a liquid consisting of approximately 3600 atoms. During each simulation, the time-evolution of the size and shape of the embryo was followed until it became indistinguishable from the liquid. These simulations provide intriguing new information on the atomic processes involved in dissolution and on the macroscopic kinetics of small clusters. Comparisons of results at different temperatures, system sizes and initial configurations are shown and the implications of these cluster dynamics for crystal growth in supercooled liquids, homogeneous nucleation, and transient nucleation are discussed.

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Temperature-dependent Self assembly of biofilaments during red blood cell sickling

10.1101/2021.03.07.433773 ◽

2021 ◽

Author(s):

Arabinda Behera ◽

Oshin Sharma ◽

Debjani Paul ◽

Anirban Sain

Keyword(s):

Self Assembly ◽

Kinetic Monte Carlo ◽

Lag Time ◽

Vital Role ◽

Temperature Dependent ◽

Opposite Case ◽

Assembly Kinetics ◽

The Mean ◽

Kinetics Of

Molecular self-assembly plays vital role in various biological functions. However, when aberrant molecules self-assemble to form large aggregates, it can give rise to various diseases. For example, the sickle cell disease and Alzheimer’s disease are caused by self-assembled hemoglobin fibers and amyloid plaques, respectively. Here we study the assembly kinetics of such fibers using kinetic Monte-Carlo simulation. We focus on the initial lag time of these highly stochastic processes, during which self-assembly is very slow. The lag time distributions turn out to be similar for two very different regimes of polymerization, namely, a) when polymerization is slow and depolymerization is fast, and b) the opposite case, when polymerization is fast and depolymerization is slow. Using temperature dependent on- and off-rates for hemoglobin fiber growth, reported in recent in-vitro experiments, we show that the mean lag time can exhibit non-monotonic behaviour with respect to change of temperature.

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