Técnicas electroquímicas aplicadas al cálculo del número de agregación y de la constante de dimerización de colorantes.

This paper envisages the potentialities derived from the electrochemical and, particularly, from the classic polarography applied t o the determination of the different medium aggregation states of dyes in solution and to the evaluation of the dimerization constants. An extensive search of the technical literatere on this topic has been made as well as the analysis of both the aggregation of the C.I Direct Red 1 and the dimerization constants at pH = 4 and pH = 7, at temperatures of 25°C and 60°C

Effects of low temperature plasma on wool and wool/nylon blend dyed fabrics

Knitted wool and wool/nylon blend dyed fabrics were treated with low temperature plasma (LTP) to achieve optimum shrink-resistance without impairing surface topography, colour or fastness to washing of the fabrics. As LTP tends to impair handle of the fabrics, both wool and wool/nylon blend fabrics were submitted to industrial softening and/or biopolymer treatments after LTP treatment, leading to hydrophilic wool and wool/nylon blend fabrics with improved shrink-resistance without any colour changes and good fastness to washing. The results obtained were compared with those obtained by an industrial shrink-resist treatment.Peer ReviewedPostprint (published version

Comparison of the effects of corona and low pressure plasma on the release of caffeine from PA66 filaments

Technical textiles for medical applications are a research expanding field. One of the added values of these materials can be suitable to contain and release active ingredients in a controlled manner. A possible alternative to obtain fabrics with controlled drug release properties could lie in the modification of fiber-active principle bonds, so that you get a proper release for each particular application. R & D currently developing drug delivery systems aims to achieve a controlled release of an active principle during a predetermined time. This is done in order to avoid the administration of several doses of drugs or cosmetic products and thus make the patient follow the therapy more easily. The influence of surface modification of fibers by low temperature plasma has been studied regarding the modification of the physical, chemical and topographical properties of the textile fibers. First studies evaluated the incorporation and release of anti-inflammatory and cosmetic drugs from different textile materials to evaluate the modulation of the drug release as the result of the surface modifications achieved by plasma treatment. The use of plasma technology to modulate the release of drugs is an original and innovative contribution. By altering the chemical bonds on the surface of textile fibers with plasma, the drug release kinetic profiles may be modified

Low-temperature plasma treatments in the design of polypropylene surgical meshes for hernia repair

One of the new trends in textile biomaterials research is to deliver active compounds locally in the surgical site from the medical device. One way to manage post-operatory infections associated with mesh implants in abdominal hernia repair surgery can be the loading of antibiotics to the surgical textile meshes. In a novel approach to design an advanced drug-delivery systems based on surgical meshes, low-temperature plasma processes have been used to tailor the surface properties of polypropylene meshes to obtain high loading of ampicillin, maintaining the biological adhesion and the antibacterial activity of the current surgical meshes [1]. Plasma treatment of polymer fibers has been commonly employed to tailor surface adhesion and wetting properties by changing the surface chemical composition [2-3]. Appropriate selection of the plasma source enables the introduction of diverse functional groups on the target surface to improve wettability, biocompatibility or to allow subsequent covalent immobilization or physical adsorption of various molecules such as dyestuffs, pharmaceutical or cosmetic active principles [4-5]. Plasma can also be used for the deposition of polymer thin coatings by the so-called plasma polymerization process [6]. By modifying the process parameters of the plasma and the precursor molecule, different kinds of biocompatible coatings can be produced, from cell-adhesive to antifouling coatings. In this work, low-temperature plasma processes have been used to tailor the surface properties of polypropylene meshes, in a novel approach, to obtain high loadings of ampicillin, maintaining the biological adhesion and the antibacterial activity of the current surgical meshes [1]. As a first-step in the design of the antibiotic-loaded surgical mesh, plasma functionalization of the polymer surface with polar oxygen groups was used to modify the polypropylene fiber surface at a nanometric level. Surface wettability was improved and the availability of chemical bonds (C-O, C=O) increased. This was employed for the subsequent attachment of ampicillin allowing increasing its loading as function of the plasma treatment time. The chemical and morphological changes produced on the surface of polypropylene fibers lead to a 3-fold improvement of the ampicillin loading in the meshes after only 3.5 s of plasma treatment. However, this plasma treatment and the subsequent loading of the ampicillin in the polypropylene fibers were related with lower fibroblast adhesion, altered morphology and enhanced chemotaxis. Thus, plasma polymerization was used as dry method to create a thin coating of polyethylene glycol with the aim of keeping the high antibiotic loadings obtained with plasma functionalization and to maintain essentially unchanged fibroblast properties such as chemotaxis or adhesion with respect to untreated meshes, fulfilling the requirement of biocompatible device for the finished antibiotic-loaded mesh. Beyond the added value brought by the loading of an antibiotic to the mesh for its release directly to the surgical site, the use of plasma processes in the design of biomaterials brings an original approach to control simultaneously physic-chemical properties and regarding the treatment of the mesh without the use of any other chemicals for the binding of the active principle with the fiber.Postprint (author's final draft

Comparison of the effects of corona and low pressure plasma on the release of caffeine from PA66 filaments

Technical textiles for medical applications are a research expanding field. One of the added values of these materials can be suitable to contain and release active ingredients in a controlled manner. A possible alternative to obtain fabrics with controlled drug release properties could lie in the modification of fiber-active principle bonds, so that you get a proper release for each particular application. R & D currently developing drug delivery systems aims to achieve a controlled release of an active principle during a predetermined time. This is done in order to avoid the administration of several doses of drugs or cosmetic products and thus make the patient follow the therapy more easily. The influence of surface modification of fibers by low temperature plasma has been studied regarding the modification of the physical, chemical and topographical properties of the textile fibers. First studies evaluated the incorporation and release of anti-inflammatory and cosmetic drugs from different textile materials to evaluate the modulation of the drug release as the result of the surface modifications achieved by plasma treatment. The use of plasma technology to modulate the release of drugs is an original and innovative contribution. By altering the chemical bonds on the surface of textile fibers with plasma, the drug release kinetic profiles may be modified

Comparison of the effects of corona and low pressure plasma on the release of caffeine from PA66 filaments

Technical textiles for medical applications are a research expanding field. One of the added values of these materials can be suitable to contain and release active ingredients in a controlled manner. A possible alternative to obtain fabrics with controlled drug release properties could lie in the modification of fiber-active principle bonds, so that you get a proper release for each particular application. R & D currently developing drug delivery systems aims to achieve a controlled release of an active principle during a predetermined time. This is done in order to avoid the administration of several doses of drugs or cosmetic products and thus make the patient follow the therapy more easily. The influence of surface modification of fibers by low temperature plasma has been studied regarding the modification of the physical, chemical and topographical properties of the textile fibers. First studies evaluated the incorporation and release of anti-inflammatory and cosmetic drugs from different textile materials to evaluate the modulation of the drug release as the result of the surface modifications achieved by plasma treatment. The use of plasma technology to modulate the release of drugs is an original and innovative contribution. By altering the chemical bonds on the surface of textile fibers with plasma, the drug release kinetic profiles may be modified.Postprint (published version