Vector diseases treatment based on intermediate complexion using textile substrates

The most efficient insect repellents are DEET (N, N-diethhyl-meta-toluamide) from synthetic origin and citronella essential oil from natural origin. However, there are other products that can also be used as insect repellents from synthetic origin, such as: DEPA (N, N-Diethyl Phenylacetamide), Icaridin, IR3535 and Permethrin and, of natural origin: Carapa guianesis, Atemisia vulgaris, Ocimim., basilicum, Cinnamomum camphora, Corymbia citriodora, Eucalyptus sp, Cymbopogon, Mentha pulegium. All those products are the basis of most commercial repellents; however the action of these repellents is of short duration, due to the volatility of the chemical compounds of these products and, therefore they offer an uncontrolled release. The authors have shown that there would be an alternative to control their release based on the complexation of the active principle (the repellent oil). Thus, the repellent will have its prolonged effect and will protect the user longer. The active principle can be used in repellent products, applied to the skin via spray or can be used on textiles. According to Lis Arias et al. when used in textiles, these products become biofunctional, enabling the delivery of assets for cosmetotextiles applications. Due to its specific response, biofunctional textiles are especially useful when the textile comes into close contact with the skin. Thus, these products can be used as insect repellents, reducing the number of infections caused by these vectorsPostprint (published version

Kinetics of dyeing in continuous circulation with direct dyes: tencel case

Due to the special characteristics of Tencel fibres, it is important to gather new data and information in order to improve our knowledge of their performance during dyeing. Kinetic equations are used to describe the behaviour of the heterogeneous dye-fibre system under isothermal conditions in order to determine the evolution of dye exhaustion versus dyeing time. Direct dyes are particularly suitable because they are physically absorbed and because they exhibit outstanding substantivity to cellulose. In addition, some of these dyes have a linear structure which ensures good correlation with structural differences in the fibres. The aim of this study is to quantify the kinetic behaviour of the Tencel-C.I. Direct Blue 1 system (one of the most common dyes in dyeing studies) by using three bi-parametric empirical dyeing-rate equations and a continuous-flow dyeing cell to obtain experimental data at six different temperatures: 30, 40, 50, 60, 70 and 80ºC. In order to check the level of adjustment of the equations we record the at three exhaustion levels: 50%, 80%, and final exhaustionPostprint (published version

Biofunctional textiles with inclusion complexes of citronella oil with ß-Cyclodextrin

Integrated medication delivery systems in biofunctional textiles can aid in the battle against vector-borne illnesses. Instead of using DEET (N,N-diethyl-m-methylbenzamide), which has drawbacks such toxic responses and skin damage, you can utilize repellents made from plants and oils. However, according to some experts, there are instances where essential oils are useless because of issues with uncontrolled release. This study looked at how citronella oil (OC) complexed with -cyclodextrin (CD) controlled the behavior of cotton (COT) and polyester (PES) textiles. The findings show that coating cotton and polyester with -cyclodextrin complexes enables control over the essential oil's release mechanism from the fabric. Optical microscopy, SEM, and FTIR were used to evaluate the complexes created; UV spectroscopy was used to determine the yield of complex formation; and controlled release was carried out in vitro. Oil complexation with CD had a yield of 63.79%, and it was found that when applied to textiles, the release, which had previously been measured in seconds, had changed to hours. The findings indicate that complexes, when modified with chemical crosslinking agents, appear to offer a potential basis for immobilizing oils and regulating their releasePostprint (published version

Inclusion complexes of citronella oil with ß-Cyclodextrin for controlled release in biofunctional textiles

Biofunctional textiles with integrated drug-delivery systems can help in the fight against vector-borne diseases. The use of repellent agents derived from plants and oils is an alternative to DEET (N,N-diethyl-m-methylbenzamide), which has disadvantages that include toxic reactions and skin damage. However, some researchers report that oils can be ineffective due to reasons related to uncontrolled release. In this work, the mechanism of control of citronella oil (OC) complexed with b-cyclodextrin (bCD) on cotton (COT) and polyester (PES) textiles was investigated. The results obtained reveal that finishing cotton and polyester with b-cyclodextrin complexes allows for control of the release mechanism of the drug from the fabric. To assess the complexes formed, optical microscopy, SEM, and FTIR were carried out; the yield of complex formation was obtained by spectroscopy in the ultraviolet region; and controlled release was performed in vitro. Oil complexation with bCD had a yield of 63.79%, and it was observed that the release, which was in seconds, moved to hours when applied to fabrics. The results show that complexes seem to be a promising basis when it comes to immobilizing oils and controlling their release when modified with chemical crosslinking agentsPostprint (published version

Microencapsulation Yield Assessment Using TGA

In this study, microcapsules containing different contents of different kinds of fragrances and with a regular spherical shape, 2,0–8,0 µm diameter, were synthesized in various core:shell ratios. Mint and cuir fragrances were successfully encapsulated in poly(urea-formaldehyde) (PUF) shell via in-situ polymerization. This was confirmed by optical microscope, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) studies. By observation from thermogravimetric analysis (TGA), it was found a relation between thermal gravimetric curves and the amount of fragrance encapsulated, which was later contrasted by ultraviolet-visible spectroscopy. In this way, comparatively, the yield percentage values can be quantitatively defined with a sufficient degree of accuracy by TGA methodPostprint (author's final draft

Biofunctional wool using ß-cyclodextrins as vehiculizer of citronella oil

The use of biopolymers such as cyclodextrin in textiles for the development of biofunctional fabrics is an alternative for the development of eco-friendly textiles. Cyclodextrins can create covalent interactions with the chemical groups available in wool, allowing the sorption of active molecules that will be released, such as the citronella oil. Therefore, this work investigates the formation of cyclodextrin complex oil applied in wool and its release mechanism. The complexes obtained and grafted to the fabric. New microstructures formed have been characterized using instruments as TGA, DLS, FTIR-ATR and SEM, besides the verification of the durability of the finish and the cytotoxicity of the obtained fabric. The release of citronella oil was, also analyzed and mathematical adjustments were performed using the approach proposed by Korsmeyer-Peppas in order to verify the release mechanisms. Results have indicated the formation of the complex and its fixation by covalent bonding, according to the FTIR-ATR specter and SEM images, have shown an non-fickian, but controlled, release profile. For this reason, the application of the complexes in wool fabrics shows promising options for the design and production of eco-friendly biofunctional materials for controlled release, allowing the oil properties to be used in textile matricesPostprint (author's final draft

Production and evaluation of antimicrobial microcapsules with essential oils using complex coacervation

Nowadays, the needs and requirements to avoid infections during surgical operations, require to be more imaginative than ever. The one-use textiles substrates that are used in hospitals can be, also, a way to transport the antibacterial effect around the own building. This is the main objective of this work; to use clothes and textiles surfaces as antibacterial systems using natural components. Microencapsulation has shown in several occasions the effectivity to protect and vehiculize active principles that can be used for medical treatments. In this case, essential oils have been used as antimicrobial agent, that when combined with shell polymers based on Chitosan of different molecular weight distribution and Arabic gum, allows them to act against Gram (+) and Gram (-) bacteria. The study of the efficiency of all the samples made gave a high value due to its character similar to hydrogels, while the determination of solids was higher when it was a question of samples made with a low molecular weight. The essential oil used has a very volatile character formed by more than 40 components and with the help of FT-IR and TGA it has been possible to corroborate that all its components were encapsulated. The impregnation of the different samples to the tissue was successful and allowed the antibacterial study to be carried out, which was carried out in duplicate on each sample and demonstrated that they have bacterial activityPostprint (published version

Vehiculation of active principles as a way to create smart and biofunctional textiles

In some specific fields of application (e.g., cosmetics, pharmacy), textile substrates need to incorporate sensible molecules (active principles) that can be affected if they are sprayed freely on the surface of fabrics. The effect is not controlled and sometimes this application is consequently neglected. Microencapsulation and functionalization using biocompatible vehicles and polymers has recently been demonstrated as an interesting way to avoid these problems. The use of defined structures (polymers) that protect the active principle allows controlled drug delivery and regulation of the dosing in every specific case. Many authors have studied the use of three different methodologies to incorporate active principles into textile substrates, and assessed their quantitative behavior. Citronella oil, as a natural insect repellent, has been vehicularized with two different protective substances; cyclodextrine (CD), which forms complexes with it, and microcapsules of gelatin-arabic gum. The retention capability of the complexes and microcapsules has been assessed using an in vitro experiment. Structural characteristics have been evaluated using thermogravimetric methods and microscopy. The results show very interesting long-term capability of dosing and promising applications for home use and on clothes in environmental conditions with the need to fight against insects. Ethyl hexyl methoxycinnamate (EHMC) and gallic acid (GA) have both been vehicularized using two liposomic-based structures: Internal wool lipids (IWL) and phosphatidylcholine (PC). They were applied on polyamide and cotton substrates and the delivery assessed. The amount of active principle in the different layers of skin was determined in vitro using a Franz-cell diffusion chamber. The results show many new possibilities for application in skin therapeutics. Biofunctional devices with controlled functionality can be built using textile substrates and vehicles. As has been demonstrated, their behavior can be assessed using in vitro methods that make extrapolation to their final applications possiblePostprint (published version

Biofunctional textiles

The aim of the chapter is to state different new possibilities that textile substrates offer for more specialized functions as Biomedical devices, Cos-metics, Skin treatment, and which are the mechanisms involved in such new applications. How to quantify the transport phenomena from the substrate to the skin, or to surrounding different medium, in which they have to be used.Textiles are covering 80% of the human body and a big percentage of that is in close contact with skin. If the system of vehiculization of the active principles is, carefully, designed, the reservoir effect of the polymeric chains of fibers can play a very interesting role in the delivery of the active prin-ciple. Microencapsulation, lipidic aggregates and nanofibers, have shown very promising experimental results. These results will help to other research-ers to develop, more accurate systems, which will valorize textile substrates, fibers and tissues for the use in more sophisticated fields.Peer ReviewedPostprint (published version

Application of lavender-oil microcapsules to functionalized PET fibers

Surface treatments for textile substrates have received significant attention from researchers around the world. Ozone and plasma treatments trigger a series of surface alterations in textile substrates that can improve the anchoring of other molecules or particles on these substrates. This work aims to evaluate the effect of ozone and plasma treatments on the impregnation of polymeric microcapsules containing lavender oil in polyester fabrics (PES). Microcapsules with walls of chitosan and gum arabic were prepared by complex coacervation and impregnated in PES, plasma-treated PES, and ozone-treated PES by padding. The microcapsules were characterized for their size and morphology and the surface-treated PES was evaluated by FTIR, TGA, SEM, and lavender release. The microcapsules were spherical in shape, with smooth surfaces. The FTIR analyses of the textile substrates with microcapsules showed bands referring to the polymers of the microcapsules, but not to the lavender; this was most likely because the smooth surface of the outer wall did not retain the lavender. The mass loss and the degradation temperatures measured by TGA were similar for all the ozone-treated and plasma-treated polyester samples. In the SEM images, spherical microcapsules and the impregnation of the microcapsules of larger sizes were perceived. Through the lavender release, it was observed that the plasma and ozone treatments interfered both with the amount of lavender delivered and with the control of the delivery.Peer ReviewedPostprint (author's final draft