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FLUORESCENT CHEMOSENSOR ENSEMBLE FOR THE DETECTION OF BENZODIAZEPINES IN AQUEOUS MEDIA
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As benzodiazepinas são prescritas para casos de ansiedade, insónia, dores musculares. Devido aos seus efeitos secundários, amplificados na presença de álcool, são classificadas como droga de abuso sexual facilitado. Este problema impacta a sociedade que necessita de combater a adulteração de bebidas alcoólicas, passando pela prevenção: se existir um sensor para detetar este tipo de compostos na escala de μM, estes episódios podem ser minimizados. Iniciou-se um estudo computacional para desenhar o melhor quimiossensor, baseado na complementa-ridade de forma e o mais promissor foi um recetor da família dos cavitandos, que apresenta uma estrutura com uma cavidade hidrofóbica capaz de acomodar pequenas moléculas orgâ-nicas no seu interior. Este cavitando foi sintetizado e caracterizado por RMN. Os recetores foram posteriormente utilizados para encapsular diferentes estiril cianinas, formando um sen-sor supramolecular capaz de alterar as suas características óticas na presença de analitos.
Alguns corantes foram completamente encapsulados no interior de cápsulas diméricas, for-madas por dois cavitandos ligados entre si por ligações de hidrogénio. A inclusão dos corantes no interior destas estruturas permite isolar completamente a molécula do seio do solvente, alterando drasticamente as suas características espetroscópicas, com uma constante de afini-dade na ordem de 103-104 M. Foram escolhidos como sensores para ensaios de competição, onde se realizaram estudos com diversos analitos. Tendo-se obtido resultados positivos tes-tou-se uma benzodiazepina sintetizada, cuja afinidade foi de 2.73x104 M-1, com um LoD de 53 μM e LoQ de 124 μM, em 5% metanol. Foi ainda possível a deteção de benzodiazepinas quando na forma de comprimido, mas o seu uso em bebidas alcoólicas foi comprometido, uma vez que o sensor tem afinidade para o etanol, gerando um sinal falso positivo.
Benzodiazepines find medical application in treating anxiety, insomnia, and muscle pain. How-ever, their side effects, particularly when combined with alcohol, have led to their categoriza-tion as facilitated sexual assault drug. This issue profoundly impacts society, requiring strate-gies to counteract the tampering of alcoholic drinks. One approach is prevention, wherein the deployment of a M detector could avoid such incidents. Consequently, a computational study was initiated to identify the optimal chemosensor based on shape complementarity. Among the screened candidates, water-soluble cavitands, characterized by a hydrophobic cavity based on resorcin[4]arene, emerged as the most promising design. The designed receptors were synthesized and characterized using NMR, UV-Visible, and Fluo-rescence techniques in the presence of several styryl cyanines. The outcome yielded a sensor with changeable optical properties in response to the presence of an analyte. Some dyes were completely included in dimeric capsules formed by two cavitands, leading to dramatic shifts in their spectroscopic properties. These assemblies showed a substantial affinity constant within the range of 103-104 M and displayed excellent stability. Consequently, these structures were chosen to serve as a self-assembled sensor in Indicator Displacement Assays. Initial experimen-tation involved various competitors with diverse characteristics, yielded positive results and this driven the subsequent assessment of the analyte of interest. In the case of a synthesized benzodiazepine, the affinity was determined to be 2.73x104 M-1, with a LoD of 53 μM and a LoQ of 124 μM, in a 5% methanol solution. Also, tablets containing benzodiazepines were able to be detected. However, the sensor's applicability to alcoholic beverages was compromised, due to its affinity towards ethanol, leading to false positive signals.
Benzodiazepines find medical application in treating anxiety, insomnia, and muscle pain. How-ever, their side effects, particularly when combined with alcohol, have led to their categoriza-tion as facilitated sexual assault drug. This issue profoundly impacts society, requiring strate-gies to counteract the tampering of alcoholic drinks. One approach is prevention, wherein the deployment of a M detector could avoid such incidents. Consequently, a computational study was initiated to identify the optimal chemosensor based on shape complementarity. Among the screened candidates, water-soluble cavitands, characterized by a hydrophobic cavity based on resorcin[4]arene, emerged as the most promising design. The designed receptors were synthesized and characterized using NMR, UV-Visible, and Fluo-rescence techniques in the presence of several styryl cyanines. The outcome yielded a sensor with changeable optical properties in response to the presence of an analyte. Some dyes were completely included in dimeric capsules formed by two cavitands, leading to dramatic shifts in their spectroscopic properties. These assemblies showed a substantial affinity constant within the range of 103-104 M and displayed excellent stability. Consequently, these structures were chosen to serve as a self-assembled sensor in Indicator Displacement Assays. Initial experimen-tation involved various competitors with diverse characteristics, yielded positive results and this driven the subsequent assessment of the analyte of interest. In the case of a synthesized benzodiazepine, the affinity was determined to be 2.73x104 M-1, with a LoD of 53 μM and a LoQ of 124 μM, in a 5% methanol solution. Also, tablets containing benzodiazepines were able to be detected. However, the sensor's applicability to alcoholic beverages was compromised, due to its affinity towards ethanol, leading to false positive signals.
Descrição
Palavras-chave
Benzodiazepinas Cavitandos Quimiossensor Supramolecular Ensaio de Subs-tituição do Indicador