Development of Nanoemulsion of Silicone Oil and Pine Oil Using Binary Surfactant System for Textile Finishing

Emulsions containing essential oils, their components or volatile semiochemicals as promising tools for insect pest and pathogen management

Most of the traditional strategies used for facing the management of insect pest and diseases have started to fail due to different toxicological issues such as the resistance of target organism and the impact on environment and human health. This has made mandatory to seek new effective strategies, which minimize the risks and hazards without compromising the effectiveness of the products. The use of essential oils, their components and semiochemicals (pheromones and allelochemicals) has become a promising safe and eco-sustainable alternative for controlling insect pest and pathogens. However, the practical applications of this type of molecules remain rather limited because their high volatility, poor solubility in water and low chemical stability. Therefore, it is required to design strategies enabling their use without any alteration of their biological and chemical properties. Oil-in-water nano/microemulsions are currently considered as promising tools for taking advantage of the bioactivity of essential oils and their components against insects and other pathogens. Furthermore, these colloidal systems also allows the encapsulation and controlled release of semiochemicals, which enables their use in traps for monitoring, trapping or mating disruption of insects, and in push-pull strategies for their behavioral manipulation. This has been possible because the use of nano/microemulsions allows combining the protection provided by the hydrophobic environment created within the droplets with the enhanced dispersion of the molecules in an aqueous environment, which favors the handling of the bioactive molecules, and limits their degradation, without any detrimental effect over their biological activity. This review analyzes some of the most recent advances on the use of emulsion-like dispersions as a tool for controlling insect pest and pathogens. It is worth noting that even though the current physico-chemical knowledge about these systems is relatively poor, a deeper study of the physico-chemical aspects of nanoemulsions/microemulsions containing essential oils, their components or semiochemicals, may help for developing most effective formulations, enabling the generalization of their use.

An approach to natural insect repellent formulations: from basic research to technological development

The incidence of dengue, Zika, chikungunya, yellow fever and malaria cases has increased significantly in the world. To avoid mosquito bites, one of the best strategies is the use of repellents. The interest in using plants as mosquito repellents has increased significantly. In this review, has been performed a bibliographic survey of the plants with repellent activity, evaluate the trends of natural repellent formulations in the scientific literature, those described in patents and commercially available products. Limonene, 1,8-cineole, geraniol, eugenol and citronellal are the active compounds that mostly appear in the essential oils of plants with repellent activity. The type of natural repellent formulation mostly widely marketed is the spray and lotion, respectively. In patents, classic formulation as emulsion was most frequently used, followed by lotions and sprays. Data collected from scientific articles and patents show that microparticles are the most widely used extended release systems nowadays for natural repellents. The citronella essential oil was the one mostly used among the classic commercially available formulations, as well as in the extended release systems described in the literature and patents. Future research must be conducted to the use of nanotechnology in the development of extended release systems containing essential oils with repellent activity produced from natural and biodegradable materials.

Review on Silicone Surfactants: Silicone-based Gemini Surfactants, Physicochemical Properties and Applications

The increasing use of silicone polymers has attracted the interest of many researchers and manufacturers for the past three decades. The silicone surfactants have excellent surface properties, of which the wetting and spreading ability is particularly noteworthy. So silicone surfactants are used in various fields, starting with textiles to agriculture. Because of this particular wetting and spreading property, silicone surfactants will be used together with conventional surfactants to achieve the desired throughput. In this paper we describe in detail the origin of silicone surfactants and various silicone surfactant compounds, as well as their physicochemical properties. We also handle various applications of silicone surfactants in agriculture, textile manufacturing, personal care and cosmetics, polyurethane foam, metal extraction, foam floatation and other industrial applications. However, the main focus is on the latest syntheses, developments and applications of newly developed tailor-made molecules.

Risk assessment due to dermal exposure of trace elements and indigo dye in jeans: Migration to artificial sweat

The concentration of a number of trace elements (Ag, Al, As, B, Ba, Be, Bi, Cd, Cr, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sr, Sn, Tl, Ti, V and Zn) were determined in 42 commercialized denim garments (jeans and shirts), being dermal exposure subsequently assessed. Migration experiments with artificial acid and basic sweat were also conducted to determine the release of these elements, as well as indigo dye. In a similar way than for the total content, Mg (124 and 99.4 µg/g) and Mn (27.1 and 7.20 µg/g) showed the highest concentrations in both artificial sweat, acid and basic, respectively. Indigo dye migrated at levels ranged from 3.22 to 7.76 mg/g, being higher in dark than in light blue fabrics. The levels of trace elements and indigo were analysed according to materials of fabric, colour, brand, and eco-labelling. Using total content and migrations rates, dermal exposure to trace elements for adult men, women and teenagers were calculated under the two sweat extractions. Non-carcinogenic and carcinogenic risks due to dermal exposure to the elements here analysed in cloths were assessed. Both risks were in the limits of safe to according to international regulations. However, the maximum exposure to Sb reached a hazard quotient (HQ) of 0.3 in clothes partially made of polyester. Despite some authors have established that indigo is an agonist of the aril receptor, health risks due to exposure to indigo dye were not calculated due the lack of toxicological data.

Fabrication and characterization of spearmint oil loaded nanoemulsions as cytotoxic agents against oral cancer cell

Spearmint oil (SMO), a commonly used essential oil for oral care products, possesses various interesting functions, especially for anticancer property. However, the application of SMO for cancer treatment is limited due to water insoluble. In the present study, nanoemulsions, which have been widely accepted as dosage forms for poorly water-soluble drugs, were selected as candidate carriers for SMO to inhibit oral cancer cell. The nanoemulsions were fabricated using phase inversion temperature method. The factors affecting formation and properties of nanoemulsions including type and amount of surfactants, oil loading and ratio of SMO to virgin coconut oil (VCO) were investigated. Among the surfactants used, the nanoemulsions containing polyoxyethylene castor oil derivatives (Kolliphor®EL; PCO35, Cremophor®RH40; PCO40, Eumulgin®CO60; PCO60) and polyoxyethylene sorbitan fatty acid esters (PSF80) showed 100% creaming after temperature cycling test indicating excellent physical stability while those containing PCO40 demonstrated more transparency and better physical stability. With an increasing amount of PCO40, the droplet size tended to decrease and was in the nano-size range (<1000 nm) after increasing to more than 5% (w/w). SMO-VCO loading also influenced on the droplet size. At 5% (w/w) PCO40, the maximum SMO-VCO loading of 25% (w/w) to attain nanoemulsions was observed. Moreover, the composition of oils had an impact on size of emulsions. The transparent nanoemulsions were only prepared in the range of SMO-VCO from 40:60 to 80:20, suggesting the optimum ratio of SMO to surfactant and the composition of oils were the critical factors for formation of nanoemulsions. NMR study disclosed that the interaction between PCO40 with both VCO and SMO should be a possible stabilization mechanism. Furthermore, the SMO-VCO nanoemulsions exhibited significant cytotoxic effect against oral carcinoma (KON) cell line using MTT assay. The finding, therefore, revealed the good feasibility of SMO-VCO nanoemulsions as novel carriers for treating of oral cancer.