Surface Activation (surface + activation)

Distribution by Scientific Domains

Selected Abstracts

Surface Activation of a Ferrimagnetic Glass,Ceramic for Antineoplastic Drugs Grafting

Enrica Vernč
A ferrimagnetic glass,ceramic, belonging to the system SiO2,Na2O,CaO,P2O5,FeO,Fe2O3, has been studied as potential carrier for antineoplastic agents, in order to exploit the combination of hyperthermia and chemotherapy. Different material pre-treatments, such as ultrasonic washing, water, or simulated body fluid dipping, were evaluated to promote the surface activation of the glass,ceramic, i.e., the hydroxyl groups formation on it. X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersion spectrometry, and wettability measurements were performed to observe the samples surface modification. The best results in terms of free hydroxyl groups exposition were obtained by dipping the samples in distilled water for 7 days at 37,°C. Two different anticancer drugs were selected in order to test the reactivity of the activated surface: cisplatinum and doxorubicin. The uptake and release of doxorubicin and cisplatinum were evaluated on glass,ceramic powders, by using UV,Visible spectrometry and graphite furnace atomic absorption spectroscopy, respectively. After 1 day of uptake at 37,°C, the quantity of doxorubicin incorporated into the glass,ceramic is 77,±,7 wt%, while only 42,±,9.6 wt% of cisplatinum is grafted onto the material surface. For both antitumoral agents, the maximum drug release after soaking in aqueous solutions at 37,°C was obtained in few hours, with a randomly distributed kinetics trend. [source]

An Integrated Atmospheric Microwave Plasma Source

Reinhold Kovacs
Abstract Atmospheric plasma processes become more and more popular in recent times. A new integrated atmospheric plasma source is presented which consists of a microwave resonator combined with a solid-state power oscillator. This allows for a very compact and efficient design of a microwave plasma source without external microwave power supply and matching units. Hydrophobic polymers have to be activated to ensure an effective painting or glueing. The performance of this new plasma source has been investigated with respect to surface activation depending on axial and radial distance to the substrate, process time, process gas, and flow velocity. Several polymeric materials have been compared. Polyethylene, polyamide, polystyrene, polypropylene, polycarbonate, and polytetrafluorineethylene show good activation results. This tool can be used especially for bulky goods and/or mass products, when a vacuum process is not possible or too expensive. [source]

Silver-Loaded Cotton/Polyester Fabric Modified by Dielectric Barrier Discharge Treatment

Mirjana Kosti
Abstract The preparation of antimicrobial silver-loaded cotton/polyester fabrics has been carried out by DBD surface activation followed by silver sorption from aqueous silver nitrate solution. A series of DBD fabric treatments was performed in order to determine the most suitable experimental conditions for the fabric surface activation. The capillarity, silver ion uptake, and copper number were used to assess the surface changes on the fabrics. An effective process has been developed to obtain antimicrobial silver-loaded Co/PES fabrics. The antimicrobial activity of the silver-loaded fabrics against different pathogens was evaluated in vitro. The quantity of bonded silver ions is enough to develop desirable antimicrobial activity in the Co/PES fabrics. [source]

Modification of poly(ethylene terephthalate) surface with attached dextran macromolecules

Yurij Stetsyshyn
Abstract BACKGROUND: Peroxidation of a poly(ethylene terephthalate) (PET) surface clears the path to the formation of biospecific polymeric layers on it. The goal of this work was the modification of a PET surface with oligoperoxides with further grafting of dextran macromolecules to this peroxidated surface. RESULTS: Novel oligoperoxides with a good affinity to PET were synthesized. They are capable of attaching to the PET surface, due to the decomposition of peroxide groups via the formation of free radicals. The alterations in surface energy and its components as a result of surface modification as well as changes in topography of the PET surface were determined. The degree of modification of the PET surface can reach 68% and depends on the following: the method of oligoperoxide and dextran deposition; the concentration of both oligoperoxide and dextran in the initial solution; and the temperature at which the modification is carried out. CONCLUSION: A new method of PET surface activation has been developed. The attachment of dextran macromolecules to modified PET surfaces is confirmed. Copyright © 2009 Society of Chemical Industry [source]

Antibacterial effect of silver nanoparticles deposited on corona-treated polyester and polyamide fabrics

Maja Radeti
Abstract The possibility of using a corona treatment (electrical discharge at atmospheric pressure) for fiber surface activation, which can facilitate the loading of silver nanoparticles (NPs) from colloids onto the polyester (PES) and polyamide (PA) fabrics and thus improve their antibacterial properties, was studied. Bactericidal efficiency and its laundering durability on silver-loaded fabrics for Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Escherichia coli were evaluated. The fiber morphology after corona treatment and subsequent loading of silver NPs was followed by SEM. Corona-treated fabrics loaded with silver NPs exhibited better antibacterial properties in comparison with untreated fabrics. In order to obtain acceptable laundering durability, it is necessary to use highly concentrated silver colloids. Copyright © 2008 John Wiley & Sons, Ltd. [source]