Desenvolvimento de biossensores amperométricos à base de acetilcolinesterase para detecção de microcistinas

Abstract

Microcystin (MC-LR) are a class hepatotoxins produced by cyanobacteria in surface water. scientific records show that the MC-LR, inhibits the action of intracellular proteins, alkaline phosphatases, but has also been proven to increase the enzyme acetylcholinesterase activity (AChE) by the MC-LR action. Therefore, this study aimed to develop biosensors amperometric based AChE enzyme for indirect detection of MC-LR. For construction of the working electrode, a powder graphite paste containing hidroxicetilcelulose (HEC), bovine serum albumin (BSA) and glutaraldehyde (Glu) was prepared. The slurry was incorporated into the AChE enzyme extracted bovine erythrocyte (EB) and electric eel (EE) as well as enzymes derived from Drosophila melanogaster was tested genetically modificadas.Também enzyme butyrylcholinesterase (BChE) obtained from human serum. A portion of the sensitive paste was deposited in the screen-printed sensor working electrode and performed characterization tests involving differential pulse voltammetry and cyclic voltammetry. cronoamperométricas readings were performed and the percentage built on activation curves (% RA) as a function of the concentration of MC-LR. Some operating conditions, such as working potential, electrochemical mediator, medium pH and substrate concentration, were optimized. enzyme activation assays showed that the EE-AChE enzyme showed best results percent relative activation (% RA) (> 10%), these values being directly proportional to the concentration of MC-LR. The biosensor developed proved accurate (CV ~ 8.32%), sensitive (Ld 0.27 μg .L-1 and LQ 0.91 μg .L-1) and accurate (recovery rates varying from 73 to 105%). The initial study proved to be the right biosensor to verify the presence of MC-LR in aquatic environments, this being then used in monitoring pollutant seven points of Bacanga River, an important aquatic ecosystem of San Luis, MA. The results indicated that there was no significant contamination.