Protein-responsive polymers for point-of-care detection of cardiac biomarker

This work describes a novel use for the polymeric film, poly(o-aminophenol) (PAP) that was made responsive to a specific protein. This was achieved through templated electropolymerization of aminophenol (AP) in the presence of protein. The procedure involved adsorbing protein on the electrode surface and thereafter electroploymerizing the aminophenol. Proteins embedded at the outer surface of the polymeric film were digested by proteinase K and then washed away thereby creating vacant sites. The capacity of the template film to specifically rebind protein was tested with myoglobin (Myo), a cardiac biomarker for ischemia. The films acted as biomimetic artificial antibodies and were produced on a gold (Au) screen printed electrode (SPE), as a step towards disposable sensors to enable point-of-care applications. Raman spectroscopy was used to follow the surface modification of the Au-SPE. The ability of the material to rebind Myo was measured by electrochemical techniques, namely electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV). The devices displayed linear responses to Myo in EIS and SWV assays down to 4.0 and 3.5 μg/mL, respectively, with detection limits of 1.5 and 0.8 μg/mL. Good selectivity was observed in the presence of troponin T (TnT) and creatine kinase (CKMB) in SWV assays, and accurate results were obtained in applications to spiked serum. The sensor described in this work is a potential tool for screening Myo in point-of-care due to the simplicity of fabrication, disposability, short time response, low cost, good sensitivity and selectivity.

Novel biosensing device for point-of-care applications with plastic antibodies grown on Au-Screen Printed Electrodes

A gold screen printed electrode (Au-SPE) was modified by merging Molecular Imprinting and Self-Assembly Monolayer techniques for fast screening cardiac biomarkers in point-of-care (POC). For this purpose, Myoglobin (Myo) was selected as target analyte and its plastic antibody imprinted over a glutaraldehyde (Glu)/cysteamine (Cys) layer on the gold-surface. The imprinting effect was produced by growing a reticulated polymer of acrylamide (AAM) and N,N′-methylenebisacrylamide (NNMBA) around the Myo template, covalently attached to the biosensing surface. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) studies were carried out in all chemical modification steps to confirm the surface changes in the Au-SPE. The analytical features of the resulting biosensor were studied by different electrochemical techniques, including EIS, square wave voltammetry (SWV) and potentiometry. The limits of detection ranged from 0.13 to 8 μg/mL. Only potentiometry assays showed limits of detection including the cut-off Myo levels. Quantitative information was also produced for Myo concentrations ≥0.2 μg/mL. The linear response of the biosensing device showed an anionic slope of ~70 mV per decade molar concentration up to 0.3 μg/mL. The interference of coexisting species was tested and good selectivity was observed. The biosensor was successfully applied to biological fluids.

O acesso das mulheres ao estudo da contabilidade

Independentemente da área de investigação, considera-se como fundamental conhecer a história, dando a possibilidade de entender o passado e perspetivar o futuro. Muitas são as descobertas e investigações feitas no âmbito da História da Contabilidade em Portugal, ainda que consideravelmente aquém da imensidão de factos ainda não estudados, possuindo o nosso país um longo caminho a percorrer no que diz respeito à investigação e descoberta de factos ligados à Contabilidade. Nesse sentido, e indo ao encontro do principal objetivo desta investigação, que consiste em conhecer e compreender o acesso das mulheres ao estudo da Contabilidade em Portugal, tendo em consideração o período do Estado Novo, a presente investigação pretende aprofundar e compreender um pequeno, mas essencial, ponto da História da Contabilidade em Portugal. Consequentemente, será traçada uma metodologia de investigação mista relativamente ao processo de recolha de dados, utilizando-se, por um lado, uma técnica de investigação qualitativa relativamente à análise documental, e como investigação quantitativa a recolha de informação através de bases de dados. Como resultados, obtiveram-se informações acerca do comportamento histórico do acesso das mulheres ao estudo da Contabilidade em Portugal, durante o Estado Novo, constatando-se, assim, os acontecimentos que estiveram na base desse mesmo comportamento, que se prevê como insatisfatório comparativamente com os valores observados relativamente aos homens. Este facto deverá ficar a dever-se ao contexto político, mas também económico e social da época, capaz de influenciar negativamente a Educação da população.