2017
Authors
Ribeiro, JA; Pereira, CM; Silva, AF; Sales, MGF;
Publication
ANALYTICA CHIMICA ACTA
Abstract
An electrochemical biosensor was developed by merging the features of Molecular Imprinting technique and Screen-Printed Electrode (SPE) for the simple and fast screening of cardiac biomarker myoglobin (Myo) in point-of-care (POC). The MIP artificial receptor for Myo was prepared by electrooxidative polymerization of phenol (Ph) on a AuSPE in the presence of Myo as template molecule. The choice of the most effective protein extraction procedure from the various extraction methods tested (mildly acidic/basic solutions, pure/mixed organic solvents, solutions containing surfactants and enzymatic digestion methods), and the optimization of the thickness of the polymer film was carefully undertaken in order to improve binding characteristics of Myo to the imprinted polymer receptor and increase the sensitivity of the MIP biosensor. The film thickness was optimized by adjusting scan rate and the number of cycles during cyclic voltammetric electropolymerization of Ph. The thickness of the polyphenol nanocoating of only few nanometres (similar to 4.4 nm), and similar to the protein diameter, brought in significant improvements in terms of sensor sensitivity. The binding affinity of MIP receptor film was estimated by fitting the experimental data to Freundlich isotherm and a similar to 8 fold increase in the binding affinity of Myo to the imprinted polymer (K-F = 0.119 +/- 0.002 ng(-1) mL) when compared to the non- imprinted polymer (K-F = 0.015 +/- 0.002 ng(-1) mL) which demonstrated excellent (re) binding affinity for the imprinted protein. The incubation of the Myo MIP receptor modified electrode with increasing concentration of protein (from 0.001 ng mL(-1) to 100 mu g mL(-1)) resulted in a decrease of the ferro/ferricyanide redox current. LODs of 2.1 and 14 pg mL(-1) were obtained from calibration curves built in neutral buffer and diluted artificial serum, respectively, using SWV technique, enabling the detection of the protein biomarker at clinically relevant levels. The prepared MIP biosensor was applied to the determination of Myo spiked serum samples with satisfactory results.
2017
Authors
Abreu, S; Caldeira, A; Costa, AR; Gomes, T; Roque, LAC;
Publication
Advances in Science, Technology and Engineering Systems
Abstract
This paper is an extension of work originally presented at the 2nd International Conference of the Portuguese Society for Engineering Education and aims to describe an interdisciplinarity teaching experiment involving three subjects of the scientific area of Mathematics and a fourth one in the area of Management. Using only one project, the students developed skills, in an integrated way, in the fields of the subjects involved. The structure of the project is described in detail. It is shown how the knowledge obtained in the different subjects is needed and how it connects together to answer the proposed challenges. We report the progress of the students' work, the main difficulties and the skills developed during this process. We conclude with a reflection on the main problems and gains that may arise in similar projects.
2017
Authors
Coelho, L; Agostinho Moreira, JA; Tavares, PB; Santos, JL; Viegas, D; de Almeida, JMMM;
Publication
SENSORS AND ACTUATORS A-PHYSICAL
Abstract
Long period fiber gratings (LPFGs) were used to monitor the characteristics of copper (Cu) thin films when annealed in air atmosphere up to similar to 680 degrees C. The wavelength and the optical power shift of the resonant bands of the LPFGs when coated with the Cu thin films, were measured as a function of the annealing temperature, and were found to exhibit a different evolution comparing to a bare LPFGs. Thin films of Cu deposited on quartz (SiO2) substrates were annealed and analyzed by XRD, SEM/EDS and Raman spectroscopy, allowing to identify the formation of two distinct oxide phases at different temperatures, cuprous (Cu2O-cuprite) and cupric (CuO-tenorite) oxides, respectively. The observed features of the resonant bands of the LPFGs were found to be associated with the Cu oxide phase transitions, indicating the possibility of using LPFGs to monitor, in real time, the oxidation states of Cu thin films by following specific characteristics of the attenuation bands. In addition, LPFGs over coated with the two distinct oxidation phases of Cu were characterized for refractive index sensing in the range between 1.300 to 1.600, leading to the conclusion that the sensitivity to the refractive index of the surrounding medium of Cu coated LPFGs sensing systems can be temperature tuned.
2017
Authors
Dörner, K; Vranas, M; Schimpf, J; Straub, IR; Hoeser, J; Friedrich, T;
Publication
Biochemistry
Abstract
2017
Authors
Silva, N; Soares, J; Shah, V; Santos, MY; Rodrigues, H;
Publication
CENTERIS 2017 - INTERNATIONAL CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS / PROJMAN 2017 - INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT / HCIST 2017 - INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES, CENTERI
Abstract
Road condition has an important role in our daily live. Anomalies in road surface can cause accidents, mechanical failure, stress and discomfort in drivers and passengers. Governments spend millions each year in roads maintenance for maintaining roads in good condition. But extensive maintenance work can lead to traffic jams, causing frustration in road users. In way to avoid problems caused by road anomalies, we propose a system that can detect road anomalies using smartphone sensors. The approach is based in data-mining algorithms to mitigate the problem of hardware diversity. In this work we used scikit-learn, a python module, and Weka, as tools for data-mining. All cleaning data process was made using python language. The fmal results show that it is possible detect road anomalies using only a smartphone. (C) 2017 The Authors. Published by Elsevier B.V.
2017
Authors
Ferreira, NS; Moreira, APT; de Sa, MHM; Sales, MGF;
Publication
SENSORS AND ACTUATORS B-CHEMICAL
Abstract
A novel device for targeting proteins with a Molecularly-Imprinted Polymer (MIP) recognition material is presented herein, by employing wax paper with conductive ink as background support. Cellulose paper was modified with paraffin wax to make it waterproof, and afterwards covered by a carbon ink to make it conductive, achieving the goal to make easy and low cost supports, and, in this case, with good detection features. Bovine Serum Albumin (BSA) was used herein as target protein. Albumin has an important role in the human body and BSA is normally used as its model protein because of its good stability and low cost. The development of BSA detection systems is important in various fields, such as biochemistry, medicine and pharmacy. Raman measurements were conducted during all preparation stages of the recognition material and electrochemical assays were used to evaluate the analytical performance of the sensor. The assembly of the device was optimized by employing different polymerization timings and monomers of different chemistries and charges. In general, longer polymerization periods and the use of a positively charged monomer benefited the analytical response. The results obtained within different calibrations indicated a linear response over a wide concentration range, from 0.005 to 100 mg/mL of BSA in buffer solution. In addition, the analytical evaluation of the device under several background solutions, including synthetic and real urine, supported the good performance of the sensor and pointed out that the principle of sensor assembly may be extended to other proteins in urine. In addition, the detection capabilities of the device proposed herein are better than other BSA sensing devices relying on electrochemical transduction.
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