Accelerating the Kinetics of Thiol Self-Assembly on GoldA Spatial Confinement Effect

1998 ◽  
Vol 120 (36) ◽  
pp. 9356-9361 ◽  
Author(s):  
Song Xu ◽  
Paul E. Laibinis ◽  
Gang-yu Liu
Keyword(s):  
Self Assembly ◽  
Confinement Effect ◽  
Spatial Confinement ◽  
Kinetics Of

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

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.

scholarly journals Controlling the Kinetics of an Enzymatic Reaction through Enzyme or Substrate Confinement into Lipid Mesophases with Tunable Structural Parameters

2020 ◽  
Vol 21 (14) ◽  
pp. 5116
Author(s):  
Marco Mendozza ◽  
Arianna Balestri ◽  
Costanza Montis ◽  
Debora Berti
Keyword(s):  
Reaction Kinetics ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Structural Parameters ◽  
Enzymatic Reaction ◽  
X Ray Scattering ◽  
Nitrophenyl Phosphate ◽  
Vis Spectroscopy ◽  
Kinetics Of ◽  
Enzyme Alkaline Phosphatase

Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H2O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV–vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.

Spatial confinement effect on the atomic structure of solid argon

2005 ◽  
Vol 122 (12) ◽  
pp. 124715 ◽  
Author(s):  
Kengo Nishio ◽  
Wataru Shinoda ◽  
Tetsuya Morishita ◽  
Masuhiro Mikami
Keyword(s):  
Atomic Structure ◽  
Confinement Effect ◽  
Spatial Confinement ◽  
Solid Argon

scholarly journals The assembly of microtubule protein in vitro. The kinetic role in microtubule elongation of oligomeric fragments containing microtubule-associated proteins

1985 ◽  
Vol 227 (2) ◽  
pp. 439-455 ◽  
Author(s):  
P M Bayley ◽  
F M M Butler ◽  
D C Clark ◽  
E J Manser ◽  
S R Martin
Keyword(s):  
Self Assembly ◽  
Protein Concentration ◽  
Wavelength Dependence ◽  
Electrophoretic Analysis ◽  
Slow Phase ◽  
Condensation Polymerization ◽  
Fast Phase ◽  
Microtubule Protein ◽  
Kinetics Of

The kinetics of assembly were studied for bovine and pig microtubule protein in vitro over a range of conditions of pH, temperature, nucleotide and protein concentration. The kinetics are in general biphasic with two major processes of similar amplitude but separated in rate by one order of magnitude. Rates and amplitudes are complex functions of solution conditions. The rates of the fast phase and the slow phase attain limiting values as a function of increasing protein concentration, and are more stringently limited at pH 6.5 than pH 6.95. Such behaviour indicates that mechanisms other than the condensation polymerization of tubulin dimer become rate-limiting at higher protein concentration. The constancy of the wavelength-dependence of light-scattering and ultrastructural criteria indicate that microtubules of normal morphology are formed in both phases of the assembly process. Electrophoretic analysis of assembling microtubule protein shows that MAP- (microtubule-associated-protein-)rich microtubules are formed during the fast phase. The rate of dissociation of oligomeric species on dilution of microtubule protein closely parallels the fast-phase rate in magnitude and temperature-dependence. We propose that the rate of this process constitutes an upper limit to the rate of the fast phase of assembly. The kinetics of redistribution of MAPs from MAP-rich microtubules may be a factor limiting the slow-phase rate. A working model is derived for the self-assembly of microtubule protein incorporating the dissociation and redistribution mechanisms that impose upper limits to the rates of assembly attainable by bimolecular addition reactions. Key roles are assigned to MAP-containing fragments in both phases of microtubule elongation. Variations in kinetic behaviour with solution conditions are inferred to derive from the nature and properties of fragments formed from oligomeric species after the rapid temperature jump. The model accounts for the limiting rate behaviour and indicates experimental criteria to be applied in evaluating the relative contributions of alternative pathways.

scholarly journals Diverse protein assembly driven by metal and chelating amino acids with selectivity and tunability

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Minwoo Yang ◽  
Woon Ju Song
Keyword(s):  
Amino Acids ◽  
Self Assembly ◽  
Protein Structures ◽  
Functional Materials ◽  
Building Blocks ◽  
Unnatural Amino Acid ◽  
Metal Coordination ◽  
Specific Chemical ◽  
Natural Building ◽  
Kinetics Of

AbstractProteins are versatile natural building blocks with highly complex and multifunctional architectures, and self-assembled protein structures have been created by the introduction of covalent, noncovalent, or metal-coordination bonding. Here, we report the robust, selective, and reversible metal coordination properties of unnatural chelating amino acids as the sufficient and dominant driving force for diverse protein self-assembly. Bipyridine-alanine is genetically incorporated into a D3 homohexamer. Depending on the position of the unnatural amino acid, 1-directional, crystalline and noncrystalline 2-directional, combinatory, and hierarchical architectures are effectively created upon the addition of metal ions. The length and shape of the structures is tunable by altering conditions related to thermodynamics and kinetics of metal-coordination and subsequent reactions. The crystalline 1-directional and 2-directional biomaterials retain their native enzymatic activities with increased thermal stability, suggesting that introducing chelating ligands provides a specific chemical basis to synthesize diverse protein-based functional materials while retaining their native structures and functions.

Monodisperse Mesoporous Microparticles Prepared by Evaporation-Induced Self Assembly Within Aerosols

2003 ◽  
Vol 775 ◽  
Author(s):  
Shailendra Rathod ◽  
G. V. Rama Rao ◽  
Brett Andrzejewski ◽  
Gabriel P. López ◽  
Timothy L. Ward ◽  
...  
Keyword(s):  
Pore Size ◽  
Self Assembly ◽  
Swelling Agent ◽  
Aerosol Generator ◽  
Amphiphilic Molecules ◽  
Brij 58 ◽  
Evaporation Induced Self Assembly ◽  
Uptake Process ◽  
Hexagonally Ordered ◽  
Kinetics Of

AbstractEvaporation induced self assembly (EISA) within microdroplets produced by a vibrating orifice aerosol generator (VOAG) has been used to produce monodisperse mesoporous silica particles. This process exploits the concentration of evaporating droplets to induce the organization of various amphiphilic molecules, effectively partitioning the silica precursor (TEOS) to the hydrophilic regions of the structure. Promotion of silica condensation, followed by removal of the surfactant, provides ordered spherical mesoporous particles. Using the VOAG we have produced highly monodisperse particles in the 5 to 10 μm diameter range. The cationic surfactant CTAB typically leads to hexagonal mesostructure with mean pore size of about 2 nm and specific surface area around 900 m2/g. We have also shown that the pore size in CTABtemplated particles can be increased to 3.8 nm by incorporating trimethylbenzene as a swelling agent. The TMB prefentially locates inside and swells the hydrophobic regions of the surfactant mesostructure. Pore size can also be varied by the choice of amphiphile. Hexagonally ordered particles have been produced using the nonionic surfactant Brij-58 and block copolymer F127. These powders possessed mean pore size 2.8 nm and 6.9 nm, respectively. The uptake of alkyl pyridinium chloride molecules have recently been measured, revealing an uptake capacity that is explained by surface adsorption (as opposed to simple pore infiltration). Kinetics of the uptake process are still be analyzed.

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

Langmuir ◽  
2012 ◽  
Vol 28 (21) ◽  
pp. 7962-7966 ◽  
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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