Search results for "surface properties"
showing 10 items of 421 documents
Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol over…
2016
AbstractA straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E…
Gold Nanoparticle Growth Monitored in situ Using a Novel Fast Optical Single-Particle Spectroscopy Method
2007
Size- and shape-dependent optical properties of gold nanorods allow monitoring their growth using a novel fast single-particle spectroscopy (fastSPS) method. FastSPS uses a spatially addressable electronic shutter based on a liquid crystal device to investigate particles randomly deposited on a substrate, orders of magnitude faster than other techniques. We use fastSPS to observe nanoparticle growth in situ on a single-particle level and extract quantitative data on nanoparticle growth.
L-Tryptophan on Cu(111): engineering a molecular labyrinth driven by indole groups
2015
The present article investigates the adsorption and molecular orientation of L-Tryptophan, which is both an essential amino acid important for protein synthesis and of particular interest for the development of chiral molecular electronics and biocompatible processes and devices, on Cu(111) using scanning tunneling microscopy and spectroscopy at 55 K and at room temperature. The arrangement of chemisorbed L-Tryptophan on the copper surface varies with both temperature and surface coverage. At low coverage, small clusters form on the surface irrespective of temperature, while at high coverage an ordered chain structure emerges at room temperature, and a tightly packed structure forms a molec…
Long-ranged and soft interactions between charged colloidal particles induced by multivalent coions
2015
Forces between charged particles in aqueous solutions containing multivalent coions and monovalent counterions are studied by the colloidal probe technique. Here, the multivalent ions have the same charge as the particles, which must be contrasted to the frequently studied case where multivalent ions have the opposite sign as the substrate. In the present case, the forces remain repulsive and are dominated by the interactions of the double layers. The valence of the multivalent coion is found to have a profound influence on the shape of the force curve. While for monovalent coions the force profile is exponential down to separations of a few nanometers, the interaction is much softer and lo…
Myoglobin on Silica: A Case Study of the Impact of Adsorption on Protein Structure and Dynamics
2013
International audience; If protein structure and function changes upon adsorption are well documented, modification of adsorbed protein dynamics remains a blind spot, despite its importance in biological processes. The adsorption of metmyoglobin on a silica surface was studied by isotherm measurements, microcalorimetry, circular dichroïsm, and UV-visible spectroscopy to determine the thermodynamic parameters of protein adsorption and consequent structure modifications. The mean square displacement and the vibrational densities of states of the adsorbed protein were measured by elastic and inelastic neutron scattering experiments. A decrease of protein flexibility and depletion in low freque…
Thymus essential oil extraction, characterization and incorporation in phospholipid vesicles for the antioxidant/antibacterial treatment of oral cavi…
2018
The aim of the work was to extract, characterize, and formulate Thymus capitatus (Tymbra capitata) essential oil in phospholipid vesicles: liposomes, glycerosomes and Penetration Enhancer-containing Vesicles (PEVs). The steam-distilled essential oil was mainly composed of carvacrol. The oil was mixed with lecithin and water to produce liposomes, or different ratios of water/glycerol or water/propylene glycol (PG) to produce glycerosomes and PG-PEVs, respectively. Cryo-TEM showed the formation of unilamellar, spherical vesicles, and light scattering disclosed that their size increased in the presence of glycerol or PG, which improved long-term stability. The formulations were highly biocompa…
Development of novel diolein–niosomes for cutaneous delivery of tretinoin: Influence of formulation and in vitro assessment
2014
Abstract This work describes innovative niosomes, composed of diolein alone or in association with the hydrophilic penetration enhancer Labrasol ® , as carriers for cutaneous drug delivery. The model drug was tretinoin and conventional, and Labrasol ® containing liposomes was used as controls to evaluate the influence of vesicle composition and the role of Labrasol ® on vesicle physico-chemical properties and performance as skin delivery system. Vesicles, prepared by the thin film hydration technique, were characterized in terms of size distribution, morphology, zeta potential, structure, incorporation efficiency, and rheological properties. The influence of carrier composition on tretinoin…
Conformational Transitions upon Maturation Rule Surface and pH-Responsiveness of α-Lactalbumin Microparticulates
2021
De novo designed protein supramolecular structures are nowadays attracting much interest as highly performing biomaterials. While a clear advantage is provided by the intrinsic biocompatibility and...
Kultivācijas apstākļu ietekme uz etanolveidojošo un pienskābes baktēriju virsmas īpašībām un fizioloģisko noturību
2013
Elektroniskā versija nesatur pielikumus
Scanning electrochemical microscopy as a probe of Ag+ binding kinetics at Langmuir phospholipid monolayers
2005
A new method has been developed for measuring local adsorption rates of metal ions at interfaces based on scanning electrochemical microscopy (SECM). The technique is illustrated with the example of Ag+ binding at Langmuir phospholipid monolayers formed at the water/air interface. Specifically, an inverted 25 microm diameter silver disc ultramicroelectrode (UME) was positioned in the subphase of a Langmuir trough, close to a dipalmitoyl phosphatidic acid (DPPA) monolayer, and used to generate Ag+ via Ag electro-oxidation. The method involved measuring the transient current-time response at the UME when the electrode was switched to a potential to electrogenerate Ag+. Since the Ag+/Ag couple…