The impact of optically rectified fields on plasmonic electrocatalysis

2019 ◽  
Vol 214 ◽  
pp. 465-477 ◽  
Author(s):  
Darby A. Nelson ◽  
Zachary D. Schultz
Keyword(s):  
Surface Charge ◽  
Optical Rectification ◽  
Electrochemical Reactivity ◽  
Plasmon Resonances ◽  
Altered Surface ◽  
The Impact

Optical rectification of plasmon resonances is shown to induce areas of altered surface charge that affect electrochemical reactivity.

scholarly journals Surface charge modulation of rifampicin-loaded PLA nanoparticles to improve antibiotic delivery in Staphylococcus aureus biofilms

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
David Da Costa ◽  
Chloé Exbrayat-Héritier ◽  
Basile Rambaud ◽  
Simon Megy ◽  
Raphaël Terreux ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Charge ◽  
Treatment Efficacy ◽  
Particle Migration ◽  
Bacterial Biofilm ◽  
Poly Lactic Acid ◽  
Retention Capacity ◽  
The Impact ◽  
Positively Charged ◽  
Antibiotic Delivery

Abstract Background After the golden age of antibiotic discovery, bacterial infections still represent a major challenge for public health worldwide. The biofilm mode of growth is mostly responsible for chronic infections that current therapeutics fail to cure and it is well-established that novel strategies must be investigated. Particulate drug delivery systems are considered as a promising strategy to face issues related to antibiotic treatments in a biofilm context. Particularly, poly-lactic acid (PLA) nanoparticles present a great interest due to their ability to migrate into biofilms thanks to their submicronic size. However, questions still remain unresolved about their mode of action in biofilms depending on their surface properties. In the current study, we have investigated the impact of their surface charge, firstly on their behavior within a bacterial biofilm, and secondly on the antibiotic delivery and the treatment efficacy. Results Rifampicin-loaded PLA nanoparticles were synthetized by nanoprecipitation and characterized. A high and superficial loading of rifampicin, confirmed by an in silico simulation, enabled to deliver effective antibiotic doses with a two-phase release, appropriate for biofilm-associated treatments. These nanoparticles were functionalized with poly-l-lysine, a cationic peptide, by surface coating inducing charge reversal without altering the other physicochemical properties of these particles. Positively charged nanoparticles were able to interact stronger than negative ones with Staphylococcus aureus, under planktonic and biofilm modes of growth, leading to a slowed particle migration in the biofilm thickness and to an improved retention of these cationic particles in biofilms. While rifampicin was totally ineffective in biofilms after washing, the increased retention capacity of poly-l-lysine-coated rifampicin-loaded PLA nanoparticles has been associated with a better antibiotic efficacy than uncoated negatively charged ones. Conclusions Correlating the carrier retention capacity in biofilms with the treatment efficacy, positively charged rifampicin-loaded PLA nanoparticles are therefore proposed as an adapted and promising approach to improve antibiotic delivery in S. aureus biofilms.

The Impact of Surface Charge on the Mechanical Behavior of High-Porosity Chalk

2012 ◽  
Vol 46 (5) ◽  
pp. 1073-1090 ◽  
Author(s):  
M. Megawati ◽  
A. Hiorth ◽  
M. V. Madland
Keyword(s):  
Mechanical Behavior ◽  
Surface Charge ◽  
High Porosity ◽  
The Impact

Effect of surface roughness on substrate-tuned gold nanoparticle gap plasmon resonances

Nanoscale ◽  
2015 ◽  
Vol 7 (9) ◽  
pp. 4250-4255 ◽  
Author(s):  
Chatdanai Lumdee ◽  
Binfeng Yun ◽  
Pieter G. Kik
Keyword(s):  
Surface Roughness ◽  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Single Particle ◽  
Gold Films ◽  
Particle Scattering ◽  
Plasmon Resonances ◽  
Scattering Spectra ◽  
The Impact ◽  
Effect Of Surface

The impact of nanoscale surface roughness on substrate-tuned gold nanoparticle plasmon resonances is demonstrated by comparing single-particle scattering spectra with simulated scattering spectra of gold nanoparticles on gold films with realistic roughness.

The impact of nano-coating on surface charge accumulation of epoxy resin insulator: characteristic and mechanism

2018 ◽  
Vol 51 (24) ◽  
pp. 245303 ◽  
Author(s):  
Bo Qi ◽  
Chunjia Gao ◽  
Yuzhen Lv ◽  
Chengrong Li ◽  
Youping Tu ◽  
...  
Keyword(s):  
Surface Charge ◽  
Epoxy Resin ◽  
Charge Accumulation ◽  
Nano Coating ◽  
The Impact

An Engineered Penicillin Acylase with Altered Surface Charge Is More Stable in Alkaline pH

1996 ◽  
Vol 799 (1 Enzyme Engine) ◽  
pp. 61-64 ◽  
Author(s):  
GABRIEL DEL RÍO ◽  
AGUSTÍN LÓPEZ-MUNGUÍA ◽  
XAVIER SOBERÓN
Keyword(s):  
Surface Charge ◽  
Penicillin Acylase ◽  
Alkaline Ph ◽  
Altered Surface

scholarly journals Theories and methods of virus isoelectric point estimation (Minireview)

2020 ◽  
Author(s):  
Joe Heffron ◽  
Brooke K. Mayer
Keyword(s):  
Surface Charge ◽  
Isoelectric Point ◽  
Electrostatic Interactions ◽  
3D Structure ◽  
Point Estimation ◽  
Electrostatic Model ◽  
Diverse Range ◽  
Enveloped Virus ◽  
The Impact ◽  
Exclusion Method

Much of virus fate, both in the environment and physical/chemical treatment, is dependent on electrostatic interactions. Developing an accurate means of predicting virion isoelectric point (pI) would help to understand and anticipate virus fate and transport, especially for viruses that are not readily propagated in the lab. One simple approach to predicting pI estimates the pH at which the sum of charges from ionizable amino acids in capsid proteins approaches zero. However, predicted pIs based on capsid charges frequently deviate by several pH units from empirically measured pIs. Recently, the discrepancy between empirical and predicted pI was attributed to the electrostatic neutralization of predictable polynucleotide-binding regions (PBRs) of the capsid interior. In this paper, we review models presupposing the A) influence of the viral polynucleotide on surface charge, or B) contribution of only exterior residues to surface charge. We then compare these models to the approach of excluding only PBRs and hypothesize a conceptual electrostatic model that aligns with this approach. The PBR exclusion method outperformed methods based on 3D structure and accounted for major discrepancies in predicted pIs without adversely affecting pI prediction for a diverse range of viruses. In addition, the PBR exclusion method was determined to be the best available method for predicting virus pI since: A) PBRs are predicted independently of the impact on pI, B) PBR prediction relies on proteome sequences rather than detailed structural models, and C) PBR exclusion was successfully demonstrated on a diverse set of viruses. These models apply to nonenveloped viruses only. A similar model for enveloped viruses is complicated by lack of data on enveloped virus pI, as well as uncertainties regarding the influence of the phospholipid envelope on charge and ion gradients.

scholarly journals Effect of fouling on removal of trace organic compounds by nanofiltration

2011 ◽  
Vol 4 (1) ◽  
pp. 71-82 ◽  
Author(s):  
S. Hajibabania ◽  
A. Verliefde ◽  
J. E. Drewes ◽  
L. D. Nghiem ◽  
J. McDonald ◽  
...  
Keyword(s):  
Surface Charge ◽  
Organic Compounds ◽  
Organic Contaminants ◽  
Layer Structure ◽  
Membrane Surface ◽  
Trace Organic Compounds ◽  
Environmental Concentration ◽  
Trace Organics ◽  
The Impact ◽  
Trace Organic

Abstract. The fate of chemical of concern is not yet fully understood during treatment of impaired waters. The aim of this paper is to assess the impact of different organic-based fouling layers on the removal of a large range of trace organics. Both model and real water samples (mixed with trace organic contaminants at environmental concentration of 2 μg l−1) were used to simulate fouling in nanofiltration under controlled environment. The new and fouled membranes were systematically characterised for surface charge, hydrophobicity and roughness. It was observed that fouling generally reduced the membrane surface charge; however, the alterations of the membrane hydrophobicity and surface roughness were dependent on the foulants composition. The rejection of charged trace organics was observed to be improved due to the increased electrostatic repulsion by fouled membranes and the adsorption of the trace organic chemicals onto organic matters. On the other hand, the removal of nonionic compounds decreased when fouling occurred, due to the presence of cake enhanced concentration polarization. The fouling layer structure was found to play an important role in the rejection of the trace organic compounds.

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