scholarly journals Controlling an electrostatic repulsion by oppositely charged surfactants towards positively charged fluorescent gold nanoclusters

2016 ◽  
Vol 18 (13) ◽  
pp. 8773-8776 ◽  
Author(s):  
Ryan D. Corpuz ◽  
Yohei Ishida ◽  
Tetsu Yonezawa
Keyword(s):  
Anionic Surfactant ◽  
Chemical Reduction ◽  
Gold Nanoclusters ◽  
Electrostatic Repulsion ◽  
Oppositely Charged ◽  
Positively Charged

An anionic surfactant enabled the first accomplish of cationic-thiolate protected fluorescent gold nanoclusters by chemical reduction.

scholarly journals Solubilization of Charged Porphyrins in Interpolyelectrolyte Complexes: A Computer Study

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 502
Author(s):  
Karel Šindelka ◽  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Dissipative Particle Dynamics ◽  
Water Soluble ◽  
Coarse Grained ◽  
Core Shell ◽  
Computer Study ◽  
Interpolyelectrolyte Complex ◽  
The Core ◽  
Porphyrin Derivatives ◽  
Oppositely Charged ◽  
Positively Charged

Using coarse-grained dissipative particle dynamics (DPD) with explicit electrostatics, we performed (i) an extensive series of simulations of the electrostatic co-assembly of asymmetric oppositely charged copolymers composed of one (either positively or negatively charged) polyelectrolyte (PE) block A and one water-soluble block B and (ii) studied the solubilization of positively charged porphyrin derivatives (P+) in the interpolyelectrolyte complex (IPEC) cores of co-assembled nanoparticles. We studied the stoichiometric mixtures of 137 A10+B25 and 137 A10−B25 chains with moderately hydrophobic A blocks (DPD interaction parameter aAS=35) and hydrophilic B blocks (aBS=25) with 10 to 120 P+ added (aPS=39). The P+ interactions with other components were set to match literature information on their limited solubility and aggregation behavior. The study shows that the moderately soluble P+ molecules easily solubilize in IPEC cores, where they partly replace PE+ and electrostatically crosslink PE− blocks. As the large P+ rings are apt to aggregate, P+ molecules aggregate in IPEC cores. The aggregation, which starts at very low loadings, is promoted by increasing the number of P+ in the mixture. The positively charged copolymers repelled from the central part of IPEC core partially concentrate at the core-shell interface and partially escape into bulk solvent depending on the amount of P+ in the mixture and on their association number, AS. If AS is lower than the ensemble average ⟨AS⟩n, the copolymer chains released from IPEC preferentially concentrate at the core-shell interface, thus increasing AS, which approaches ⟨AS⟩n. If AS>⟨AS⟩n, they escape into the bulk solvent.

Influence of the size and charge of gold nanoclusters on complexation with siRNA: a molecular dynamics simulation study

2015 ◽  
Vol 17 (45) ◽  
pp. 30307-30317 ◽  
Author(s):  
Sathish Kumar Mudedla ◽  
Ettayapuram Ramaprasad Azhagiya Singam ◽  
Kanagasabai Balamurugan ◽  
Venkatesan Subramanian
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Molecular Dynamics Simulations ◽  
Simulation Study ◽  
Gold Nanoclusters ◽  
Dynamics Simulation ◽  
Classical Molecular Dynamics ◽  
Dynamics Simulations ◽  
Positively Charged

The complexation of siRNA with positively charged gold nanoclusters has been studied using classical molecular dynamics simulations.

scholarly journals Compositional and Temperature Effects on the Rheological Properties of Polyelectrolyte–Surfactant Hydrogels

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 927 ◽  
Author(s):  
Jiří Smilek ◽  
Sabína Jarábková ◽  
Tomáš Velcer ◽  
Miloslav Pekař
Keyword(s):  
Ionic Strength ◽  
Rheological Properties ◽  
Surfactant Concentration ◽  
Background Electrolyte ◽  
Effect Of Temperature ◽  
Physical Interactions ◽  
Chain Conformations ◽  
Oppositely Charged ◽  
Electrolyte Ph ◽  
Positively Charged

The rheological properties of hydrogels prepared by physical interactions between oppositely charged polyelectrolyte and surfactant in micellar form were studied. Specifically, hyaluronan was employed as a negatively charged polyelectrolyte and Septonex (carbethopendecinium bromide) as a cationic surfactant. Amino-modified dextran was used as a positively charged polyelectrolyte interacting with sodium dodecylsulphate as an anionic surfactant. The effects of the preparation method, surfactant concentration, ionic strength (the concentration of NaCl background electrolyte), pH (buffers), multivalent cations, and elevated temperature on the properties were investigated. The formation of gels required an optimum ionic strength (set by the NaCl solution), ranging from 0.15–0.3 M regardless of the type of hydrogel system and surfactant concentration. The other compositional effects and the effect of temperature were dependent on the polyelectrolyte type or its molecular weight. General differences between the behaviour of hyaluronan-based and cationized dextran-based materials were attributed to differences in the chain conformations of the two biopolymers and in the accessibility of their charged groups.

A positively charged tight UF membrane and its properties for removing trace metal cations via electrostatic repulsion mechanism

2019 ◽  
Vol 373 ◽  
pp. 168-175 ◽  
Author(s):  
Ming-Yong Zhou ◽  
Peng Zhang ◽  
Li-Feng Fang ◽  
Bao-Ku Zhu ◽  
Jian-Li Wang ◽  
...  
Keyword(s):  
Trace Metal ◽  
Metal Cations ◽  
Electrostatic Repulsion ◽  
Positively Charged

scholarly journals An extension of Maxwell's electro-magnetic theory of light to include dispersion, metallic reflection, and allied phenomena

1898 ◽  
Vol 63 (389-400) ◽  
pp. 91-92
Keyword(s):  
Homogeneous Medium ◽  
Potential Difference ◽  
Electric Moment ◽  
Magnetic Theory ◽  
Electro Magnetic ◽  
Oppositely Charged ◽  
Positively Charged

A dielectric, like an electrolyte, is assumed to consist of molecules, each comprising, in the simplest case, two oppositely charged atoms at a definite distance apart. In a homogeneous medium, when not subjected to electric strain, these molecules will be arranged in such a manner that any element of volume will possess no resultant electric moment. If a definite potential difference be maintained between any two parallel planes in the medium, the positively charged atoms will move to points of lower, and the negatively charged atoms to points of higher, potential.

scholarly journals Cetylpyridinium chloride produces increased zeta-potential on Salmonella Typhimurium cells, a mechanism of the pathogen’s inactivation

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Yagmur Yegin ◽  
Jun K. Oh ◽  
Mustafa Akbulut ◽  
Thomas Taylor
Keyword(s):  
Zeta Potential ◽  
Salmonella Typhimurium ◽  
Membrane Lipids ◽  
Cetylpyridinium Chloride ◽  
Membrane Integrity ◽  
Electrostatic Repulsion ◽  
Phase Interaction ◽  
Human Pathogens ◽  
Two Phase ◽  
Oppositely Charged

Abstract Cetylpyridinium chloride (CPC) is a quaternary ammonium sanitizer approved for fresh poultry animal carcass sanitization from microbial human pathogens, such as Salmonella enterica. Nonetheless, the interactions of CPC with Salmonella cells, and the mechanism of the sanitizer’s neutralization by lecithin remains largely unknown. This study aimed to investigate the interaction of CPC with lecithin and Salmonella Typhimurium to determine the interactions of the sanitizer and neutralizer impacting the bacterium’s survival. Application of 0.8% CPC is proposed to produce loss of microbial membrane integrity with loss of electrostatic repulsion between individual cells, resulting in the eventual emulsification of membrane lipids with cytoplasmic contents leakage. Our findings point to a two-phase interaction between CPC and lecithin impacting S. Typhimurium survival. The first consists of electrostatic attraction and charge neutralization between oppositely charged components of pathogen cell and CPC. The second involves formation of aggregates between sanitizer and pathogen, or between sanitizer, pathogen membrane lipids, and lecithin.

Deposition of Functionalised Gold Nanoparticles by the Layer-by-Layer Electrostatic Technique

2003 ◽  
Vol 789 ◽  
Author(s):  
S. Paul ◽  
M. Palumbo ◽  
M. C. Petty ◽  
N. Cant ◽  
S. D. Evans
Keyword(s):  
Gold Nanoparticles ◽  
Silicon Substrate ◽  
Coulomb Blockade ◽  
Quantum Mechanical ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Solid Substrates ◽  
Oppositely Charged ◽  
Positively Charged

ABSTRACTIntensive research is currently underway to exploit the intriguing optical and electronic behaviour of nano-sized particles. The basis of the unique properties of these particles is the smallness of their size; dimensions on the nanometre scale can result in interesting quantum mechanical phenomena, such as Coulomb blockade. There are currently a number of ways by which the nanoparticles can be deposited onto solid substrates. Here, we report on the use of the layer-by-layer electrostatic method, which has shown much promise in the context of deposition of thin films of certain organic materials. In this technique, layers of oppositely charged materials are generated by dipping an appropriate substrate into solutions of polyelectrolytes. For example, the polybases poly(ethyleneimine) (PEI), when adsorbed on a substrate, produce a positively charged surface. We have deposited carboxylic acid (-COOH) derivatised gold nanoparticles onto a PEI-coated silicon substrate and an amine funtionalised silicon substrate. The distribution of the gold nanoparticles was compared using atomic force microscopy.

Sign in / Sign up

Export Citation Format

Share Document