RESUMEN
The encapsulation of bioactive agents through the utilization of biodegradable nanoparticles is a topic of considerable scientific interest. In this study, microcapsules composed of chitosan (CS) and Arabic gum (GA) nanoparticles were synthesized, encapsulating oregano essential oil (OEO) through Pickering emulsions and subsequent spray drying. The optimization of hybrid chitosan and Arabic gum (CS-GA) nanoparticle formation was carried out via complex coacervation, followed by an assessment of their behavior during the formation of the emulsion. Measurements of the size, contact angle, and interfacial tension of the formed complexes were conducted to facilitate the development of Pickering emulsions for encapsulating the oil under the most favorable conditions. The chitosan-Arabic gum capsules were physically characterized using scanning electron microscopy and fitted to the Beerkan estimation of soil transfer (BEST) model to determine their size distribution. Finally, the OEO encapsulation efficiency was also determined. The optimum scenario was achieved with the CS-GA 1-2 capsules at a concentration of 2% wt, featuring a contact angle of 89.1 degrees, which is ideal for the formation of oil/water (O/W) emulsions. Capsules of approximately 2.5 µm were obtained, accompanied by an encapsulation efficiency of approximately 60%. In addition, the hybrid nanoparticles that were obtained showed high biodegradability. The data within our study will contribute fundamental insights into CS-GA nanoparticles, and the quantitatively analyzed outcomes presented in this study will hold utility for forthcoming applications in environmentally friendly detergent formulations.
RESUMEN
Surfactants can be found in an ever-widening variety of products and applications, in which the combination of several types of surfactants is used to reinforce their properties, looking for synergistic effects between them. After use, they tend to be discarded into wastewater, ending up in aquatic bodies with concerning harmful and toxic effects. The aim of this study is the toxicological assessment of three anionic surfactants (ether carboxylic derivative, EC) and three amphoteric surfactants (amine-oxide-based, AO), individually and in binary mixtures of them (1:1 w/w), to bacteria Pseudomonas putida and marine microalgae Phaeodactylum tricornutum. Critical Micelle Concentration (CMC) was determined to demonstrate the capacity to reduce surface tension and the toxicity of the surfactants and mixtures. Zeta potential (ζ-potential) and micelle diameter (MD) were also determined to confirm the formation of mixed surfactant micelles. The Model of Toxic Units (MTUs) was used to quantify the interactions of surfactants in binary mixtures and to predict if the concentration addition or response addition principle can be assumed for each mixture. The results showed a higher sensitivity of microalgae P. tricornutum to the surfactants tested and their mixtures than bacteria P. putida. Antagonism toxic effects have been detected in the mixture of EC + AO and in one binary mixture of different AOs; this is to say, the mixtures showed lower toxicity than expected.
