Sensores nanométricos à base de ácido 10,12-pentacosadiinóico (PCDA) e ß-ciclodextrina para detecção de ivermectina

Abstract

Brazil achieved a record cattle herd production of 234.4 million animals in 2022, representing an increase of 4.3% compared to the previous year, according to data from IBGE (Brazilian Institute of Geography and Statistics). As a consequence, the demand for treatment and use of medicines to ensure the survival and reproduction of cattle has also increased. Broad-spectrum antiparasitics, mainly from the macrocyclic lactone family, have been widely used for these purposes. Residues of these medicines can remain in the animal organism for a certain period and consequently be present in tissues and milk, which can lead to the inhibition of dairy cultures important for the industry and various problems related to public health. As a result, the demand for food safety and ways to detect compounds and/or residues of these medicines in products of animal origin, such as milk, has grown considerably. The techniques currently used require time and have a high cost of implementation, often making routine analysis unfeasible. To improve the efficiency of this process, polydiacetylenes (PDAs) emerge as potential candidates for colorimetric sensors, as they have unique structural and optical characteristics, which allow color changes based on external stimuli. In the first stage of this research, systems containing PDA/ß-cyclodextrin in three concentrations (1, 2 and 3 mM) were studied for potential use as sensors and preliminary results found that in a 1:2 ratio, the complex maintained its blue color , without major changes and became promising for application. In the second stage of the research, the interaction and colorimetric response between this system and ivermectin (IVR) and morphology were studied, noting that there was a chromatic change in the systems after interaction and that after this contact with IVR there was aggregation of the vesicles due to to the possible breakage or fusion of nanostructures. In the third part of this study, molecular interactions were investigated using nuclear magnetic resonance (NMR) spectroscopy and it was proven that the system was responsive to IVR. However, investing in more economical alternatives would allow for large-scale testing, benefiting not only consumers, but also the global economy. And although there is still much to be done, it is believed that this study can significantly contribute to advances in research related to the use of systems composed of PDA vesicles/receptors, for the detection of numerous molecules.