Construção, caracterização e aplicação analítica de microdispositivos enzimáticos

Abstract

The focus of this work is the development and application of enzymatic microreactors aiming their application through flow injection analysis systems. On top of that, two polymeric substrates were used for the evaluation of enzyme immobilization: one based on poly (methyl methacrylate) (PMMA) and another baed on a bisphenol-A diglycidyl ether resin (BADGE). A CO2 laser printer was used to fabricate the devices at the desired dimensions. For the success of the immobilization systems have been pretreated with polyethyleneimine (PEI) in order to introduce reactive functional groups on the surface of the starting materials. In a first study, based on PMMA modification, the activation of the material was achieved after treating microchannels with PEI in dimethylsulfoxide (DMSO). In the second case, treatment with PEI involved simply a mechanical mixture of the two materials, in order to cure the resin. After activation of materials with PEI, the enzymes were immobilized after passage of a mixture of glutaraldehyde (a spacer agent) and enzymes. Among the enzymes studied are glucose oxidase (GOx), ascorbate oxidase (AAO), catalase (CAT), dehydrogenase glutamate (GDH), and a hybrid system based on the simultaneous immobilization of the enzymes glucose oxidase (GOx) and horseradish peroxidase (HPR). The characterization of the developed systems was primarily done by Raman spectroscopy. Moreover, application of some of the proposed systems to real samples and calculation of kinetic and operational parameters are presented during the study. These evaluations were made with detection systems based on electrochemical and visible spectroscopy techniques, all developed at the laboratory. One great benefit of the developed systems, are the speed and simplicity of implementation the immobilization process and operation of the devices.