Search

Your search keyword '"Arnebrant, Thomas"' showing total 507 results
Start Over Author "Arnebrant, Thomas"
507 results on '"Arnebrant, Thomas"'

3. Electrochemical insights into layered assemblies of silver nanoparticles, poly‐L‐lysine, and bovine serum albumin.

Author

Seumo Tchekwagep, Patrick Marcel, Žalnėravičius, Rokas, Péguy Nanseu‐Njiki, Charles, Ngameni, Emmanuel, Arnebrant, Thomas, and Ruzgas, Tautgirdas

Subjects
SILVER nanoparticles, SERUM albumin, TRANSMISSION electron microscopy, SILVER ions, ZETA potential
Abstract

This study presents a comprehensive exploration of the electrochemical behavior of layer‐by‐layer assemblies comprising silver nanoparticles (AgNPs), poly‐l‐lysine (PLL), and bovine serum albumin (BSA) on gold surfaces. AgNPs were synthesized using the reduction of silver ions with the synergy of ascorbic acid and citrate in the presence of sodium chloride. The obtained silver nanoparticles were characterized using transmission electron microscopy, dynamic light scattering and UV‐Vis spectroscopy. A typical preparation produced AgNPs with a plasmon peak at 402 nm, a diameter of 27.5 nm and zeta potential of −37 mV. Employing a drop‐coating approach, we successfully achieved stable multilayers of AgNPs, PLL, and BSA. Cyclic voltammetry revealed well‐defined, bell‐shaped oxidation and reduction peaks of AgNPs within the multilayers, demonstrating complete conversion to AgCl and back to Ag. Notably, the stripping of AgNPs on a monolayer of PLL prepared at pH 4.00 resulted in the highest current intensity, contrasting with lower intensities observed for PLL monolayers prepared at pH 7.01 and pH 9.01. Despite the absence of a splitting reduction peak in the presence of biopolymer materials, a noteworthy observation emerged: the peak splitting exclusively occurred when PLL/AgNP layers, terminated with PLL, were exposed to BSA in the solution. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

23. MUC5B mucin films under mechanical confinement : A combined neutron reflectometry and atomic force microscopy study.

Author

Gonzalez-Martinez, Juan F, Boyd, Hannah, Gutfreund, Philipp, Welbourn, Rebecca J L, Robertsson, Carolina, Wickström, Claes, Arnebrant, Thomas, Richardson, Robert M, Prescott, Stuart W, Barker, Robert, Sotres, Javier, Gonzalez-Martinez, Juan F, Boyd, Hannah, Gutfreund, Philipp, Welbourn, Rebecca J L, Robertsson, Carolina, Wickström, Claes, Arnebrant, Thomas, Richardson, Robert M, Prescott, Stuart W, Barker, Robert, and Sotres, Javier

Abstract

HYPOTHESIS: Among other functions, mucins hydrate and protect biological interfaces from mechanical challenges. Mucins also attract interest as biocompatible coatings with excellent lubrication performance. Therefore, it is of high interest to understand the structural response of mucin films to mechanical challenges. We hypothesized that this could be done with Neutron Reflectometry using a novel sample environment where mechanical confinement is achieved by inflating a membrane against the films. EXPERIMENTS: Oral MUC5B mucin films were investigated by Force Microscopy/Spectroscopy and Neutron Reflectometry both at solid-liquid interfaces and under mechanical confinement. FINDINGS: NR indicated that MUC5B films were almost completely compressed and dehydrated when confined at 1 bar. This was supported by Force Microscopy/Spectroscopy investigations. Force Spectroscopy also indicated that MUC5B films could withstand mechanical confinement by means of steric interactions for pressures lower than ∼ 0.5 bar i.e., mucins could protect interfaces from mechanical challenges of this magnitude while keeping them hydrated. To investigate mucin films under these pressures by means of the employed sample environment for NR, further technological developments are needed. The most critical would be identifying or developing more flexible membranes that would still meet certain requirements like chemical homogeneity and very low roughness.

Published
2022
Full Text
View/download PDF

38. Effect of nonionic and amphoteric surfactants on salivary pellicles reconstituted in vitro

Author

Barker, Robert, Gonzalez‐Martinez, Juan, Welbourn, Rebecca J.L., Ma, Kun, Li, Peixun, Gutfreund, Philipp, Klechikov, Alexey, Arnebrant, Thomas, Sotres, Javier, Barker, Robert, Gonzalez‐Martinez, Juan, Welbourn, Rebecca J.L., Ma, Kun, Li, Peixun, Gutfreund, Philipp, Klechikov, Alexey, Arnebrant, Thomas, and Sotres, Javier

Abstract

Surfactants are important components of oral care products. Sodium dodecyl sulfate (SDS) is the most common because of its foaming properties, taste and low cost. However, the use of ionic surfactants, especially SDS, is related to several oral mucosa conditions. Thus, there is a high interest in using non‐ ionic and amphoteric surfactants as they are less irritant. To better understand the performance of these surfactants in oral care products, we investigated their interaction with salivary pellicles i.e., the proteinaceous films that cover surfaces exposed to saliva. Specifically, we focused on pentaethylene glycol monododecyl ether (C12E5) and cocamidopropyl betaine (CAPB) as model nonionic and amphoteric surfactants respectively, and investigated their interaction with reconstituted salivary pellicles with various surface techniques: Quartz Crystal Microbalance with Dissipation, Ellipsometry, Force Spectroscopy and Neutron Reflectometry. Both C12E5 and CAPB were gentler on pellicles than SDS, removing a lower amount. However, their interaction with pellicles differed. Our work indicates that CAPB would mainly interact with the mucin components of pellicles, leading to collapse and dehydration. In contrast, exposure to C12E5 had a minimal effect on the pellicles, mainly resulting in the replacement/solubilisation of some of the components anchoring pellicles to their substrate.

Published
2021

39. Salivary Pellicles

Author

Lindh, Liselott, primary, Aroonsang, Watcharapong, additional, Sotres, Javier, additional, and Arnebrant, Thomas, additional

Published
2014
Full Text
View/download PDF

41. Coarse-grained modeling of proline rich protein 1 (PRP-1) in bulk solution and adsorbed to a negatively charged surface

Author

Skepo, Marie, Linse, Per, and Arnebrant, Thomas

Subjects
Proline -- Chemical properties, Polyelectrolytes -- Chemical properties, Monte Carlo method -- Usage, Chemicals, plastics and rubber industries
Abstract

Structural properties of the acidic proline rich protein (PRP)-1 of salivary origin in bulk solution and adsorbed onto a negatively charged surface were studied by Monte Carlo simulations. PRP-1 has a compact structure in salt free bulk solutions whereas at high concentration the protein becomes more extended and the conformational behavior of PRP-1 in bulk solution and at charged surface as well as its propensity to adsorb to surfaces with the same net charge are rationalized by the block polyampholytic character of the protein.

Published
2006

47. A comparison between the structures of reconstituted salivary pellicles and oral mucin (MUC5B) films

Author

Boyd, Hannah, Gonzalez-Martinez, Juan F., Welbourn, Rebecca J.L., Gutfreund, Philipp, Klechikov, Alexey, Robertsson, Carolina, Wickström, Claes, Arnebrant, Thomas, Barker, Robert, Sotres, Javier, Boyd, Hannah, Gonzalez-Martinez, Juan F., Welbourn, Rebecca J.L., Gutfreund, Philipp, Klechikov, Alexey, Robertsson, Carolina, Wickström, Claes, Arnebrant, Thomas, Barker, Robert, and Sotres, Javier

Abstract

Hypothesis: Salivary pellicles i.e., thin films formed upon selective adsorption of saliva, protect oral surfaces against chemical and mechanical insults. Pellicles are also excellent aqueous lubricants. It is generally accepted that reconstituted pellicles have a two-layer structure, where the outer layer is mainly composed of MUC5B mucins. We hypothesized that by comparing the effect of ionic strength on reconstituted pellicles and MUC5B films we could gain further insight into the pellicle structure. Experiments: Salivary pellicles and MUC5B films reconstituted on solid surfaces were investigated at different ionic strengths by Force Spectroscopy, Quartz Crystal Microbalance with Dissipation, Null Ellipsometry and Neutron Reflectometry. Findings: Our results support the two-layer structure for reconstituted salivary pellicles. The outer layer swelled when ionic strength decreased, indicating a weak polyelectrolyte behavior. While initially the MUC5B films exhibited a similar tendency, this was followed by a drastic collapse indicating an interaction between exposed hydrophobic domains. This suggests that mucins in the pellicle outer layer form complexes with other salivary components that prevent this interaction. Lowering ionic strength below physiological values also led to a partial removal of the pellicle inner layer. Overall, our results highlight the importance that the interactions of mucins with other pellicle components play on their structure.

Published
2020

48. Consecutive selective adsorption of pentamidine and phosphate biomolecules on a self-assembled layer: reversible formation of a chemically selective coating

Author

Sellergen, Borje, Swietlow, Aleksander, Arnebrant, Thomas, and Unger, Klaus

Subjects
Coatings -- Research, Biomolecules -- Research, Monomolecular films -- Research, Molecular structure -- Research, Chemistry
Abstract

In situ ellipsometric film thickness measurements, FT-IR external reflectance spectroscopy, and potentiometric measurements indicated that the amphiphile pentamidine (PAM), a bisbenzamidine, associated by self-assembly with a preformed self-assembled monolayer of a mercaptoalkanoic acid on gold. The structural properties of PAM and the nature of the substrate were ideal for the formation of a densely packed monolayer. This process was fully reversible, as demonstrated by changing the pH of the surrounding medium. Thus, disassembly - reassembly occurred when the pH was cycled between 8.7 and 3. The bilayer structure, featuring a positively charged amidinium surface, was subsequently used for selective adsorption of phosphate biomolecules. Thus, selective binding of adenosine and inositol phosphates ([K.sub.a] = 5 x [10.sup.4] [M.sup.-1] for ATP) to the surface, as well as strong binding of DNA - oligonucleotides, was monitored by in situ ellipsometry. This system suggests a new approach to chemical sensing, based on the reversible formation of a chemically selective coating.

Published
1996

Catalog

Books, media, physical & digital resources
See catalog results