Monitoramento do consumo de oxigênio mitocondrial : sensor quimioresistor para oxigênio dissolvido baseado em nanocompósito de azo polímero-grafeno

No presente estudo, foi desenvolvido um sensor impedimétrico baseado em filme polimérico nanocompósito de grafeno com poli-Bismarck Brown Y para analise da capacidade respiratória dos complexos constituintes da cadeia transportadora de elétrons. O filme “mesclado" foi fabricado visando somar as propriedades químicas dos azopolímeros com as qualidades do grafeno. Sua eletrossíntese se deu por técnica de eletropolimerização e suas propriedades físico-químicas e morfológicas investigadas através de espectroscopia de impedância eletroquímica (EIE) e microscopia eletrônica de varredura (MEV), respectivamente. Sua performance frente a molécula de oxigênio dissolvido demonstra uma diminuição dos valores de impedância real (Z’) com o aumento da concentração de oxigênio, revelando um aumento da condutividade eletrônica conferido pela interação química entre os grupos hidrazina do filme e o oxigênio dissolvido. O sensor teve seus parâmetros otimizados, alcançando sensibilidade de 16,9 k cm² L mmol-1, além de boa seletividade e repetibilidade. Por fim, o sensor cronoimpedimetrico foi posto à prova, avaliando o consumo de oxigênio mitocondrial de tecidos de ratos fumantes, exercitados, fumantes exercitados e do grupo controle. O sensor demonstrou sucesso ao ser capaz de analisar a capacidade respiratória dos grupos de animais e demonstrar que o grupo exercitado obteve os maiores valores de respiração ROUTINE, enquanto o grupo fumante teve seus valores significativamente menores comparados ao grupo controleFil: Olean-Oliveira, A. . Universidade Estadual PaulistaFil: Teixeira, M. S. F. Universidade Estadual Paulist

Application of botryosphaeran as a carbon black adherent on a glassy carbon electrode for the electrochemical determination of cyclobenzaprine

The present work describes the performance of a new voltammetric sensor based on the modification of glassy carbon electrodes (GCE) with carbon black (CB) and botryosphaeran (BOT) (CB-BOT/GCE) for the electroanalytical determination of cyclobenzaprine. BOT is a fungal exocellular (1→3)(1→6)-β-ᴅ-glucan, which was used to improve the adherence of CB onto the surface of GCE. The electrochemical characterisation was performed by electrochemical impedance spectroscopy which showed an improvement in the transfer of electrons on the surface of the sensor developed in relation to the unmodified (bare) GCE. The voltammetric behaviour of cyclobenzaprine was studied using bare GCE, BOT/GCE, CB/GCE, and CB-BOT/GCE. All electrodes presented an oxidation peak (+ 1.0 V) for cyclobenzaprine, while the cyclobenzaprine peak intensity on CB-BOT/GCE was found to be 480% higher than the bare GCE. Through employing square-wave voltammetry, the analytical curve was found to be linear over the concentration range of 2.0 to 20.6 μmol L−1 (in 0.1 mol L−1 NaCl solution) with a detection limit (based on 3-sigma) of 0.63 μmol L−1. The developed electrochemical sensor exhibited excellent sensitivity and selectivity and was successfully applied for the voltammetric determination of cyclobenzaprine in pharmaceutical, biological, and environmental samples for the first time using the CB-BOT/GCE electrochemical sensing platform

Nanocomposite Materials Based on Electrochemically Synthesized Graphene Polymers: Molecular Architecture Strategies for Sensor Applications

The use of graphene and its derivatives in the development of electrochemical sensors has been growing in recent decades. Part of this success is due to the excellent characteristics of such materials, such as good electrical and mechanical properties and a large specific surface area. The formation of composites and nanocomposites with these two materials leads to better sensing performance compared to pure graphene and conductive polymers. The increased large specific surface area of the nanocomposites and the synergistic effect between graphene and conducting polymers is responsible for this interesting result. The most widely used methodologies for the synthesis of these materials are still based on chemical routes. However, electrochemical routes have emerged and are gaining space, affording advantages such as low cost and the promising possibility of modulation of the structural characteristics of composites. As a result, application in sensor devices can lead to increased sensitivity and decreased analysis cost. Thus, this review presents the main aspects for the construction of nanomaterials based on graphene oxide and conducting polymers, as well as the recent efforts made to apply this methodology in the development of sensors and biosensors