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Publications

Voltammetric aptasensors for protein disease biomarkers detection: a review

Publication . Meirinho, Sofia G.; Dias, L.G.; Peres, António M.; Rodrigues, Lígia R.

An electrochemical aptasensor is a compact analytical device where the bioreceptor (aptamer) is coupled to a transducer surface to convert a biological interaction into a measurable signal (current) that can be easily processed, recorded and displayed. Since the discovery of the Systematic Evolution of Ligands by Enrichment (SELEX) methodology, the selection of aptamers and their application as bioreceptors has become a promising tool in the design of electrochemical aptasensors. Aptamers present several advantages that highlight their usefulness as bioreceptors such as chemical stability, cost effectiveness and ease of modification towards detection and immobilization at different transducer surfaces. In this review, a special emphasis is given to the potential use of electrochemical aptasensors for the detection of protein disease biomarkers using voltammetry techniques. Methods for the immobilization of aptamers onto electrode surfaces are discussed, as well as different electrochemical strategies that can be used for the design of aptasensors.

2016Journal article

Open access

Susceptibility testing of Candida albicans and Candida glabrata to Glycyrrhiza glabra L.

Publication . Martins, Natália; Costa-Oliveira, Sofia; Melo, Luís D.R.; Ferreira, Isabel C.F.R.; Azeredo, Joana; Henriques, Mariana; Silva, Sónia; Martins N.

Medicinal plants and their botanical formulations have gained a pivotal attention among scientific researchers mainly due to its action as health promoters. Licorice (Glycyrrhiza glabra L.) constitutes a great example, with an increasingly evidenced antimicrobial potential. Opportunistic yeast infections constitute an alarming public health problem, highly exacerbated by the inefficacy of antifungal drugs and the increase of drug-resistant microorganisms, being Candida species one of the most common invaders. The present work aims to assess Candida glabrata and Candida albicans susceptibility to G. glabra methanol: water extract by using flow cytometry and transmission electron microscopy techniques. After 5 min, licorice extract (1.5 mg/mL) altered Candida membrane potential. Within an hour, it induced primary damages on Candida species cells, causing cell cytoplasm disorganization with high evidence of cell membrane invaginations, making cells turgid. Thus, based on the current findings, licorice extract seems to be a promising anti-Candida agent, without presenting any toxic potential at the effective concentrations used.

2017Journal article

Open access

Electrochemical Multi-Sensors Device Coupled with Heurisic or Meta-Heuristic Selection Algorithms for Single-Cultivar Oilive Oil Classification

Publication . Peres, António M.; Veloso, Ana C.A.; Pereira, J.A.; Dias, L.G.

Apply heuristic and meta-heuristic variable selection algorithms. Best Approach? To reduce the number of sensors included in a linear discriminant analysis (LDA) model, avoiding the use of redundant information and multicollinearity problems To classify EVOOs according to cultivar and crop year. The Practical Aim: Improving the discrimination of EVOOs that are highly appreciated and an important componente of the Mediterranean diet, being prone to frauds involving mislabelling and adulteration.

2014Conference object

Open access

Gliadins in Foods and the Electronic Tongue

Publication . Veloso, Ana C.A.; Dias, L.G.; Rodrigues, Lígia R.; Peres, António M.

The commercialization of safe foods is a main concern and should be ensured throughout the entire food supply chain. So, fast, sensitive, and reliable analytical methods are needed to identify food-related specific hazards, ensuring consumers' protection and avoiding health problems. This chapter is focused on the emerging (bio)sensors to detect the heat-stable allergen gliadin in gluten-free foods. A brief overview concerning gliadin and its relation to celiac disease is provided. Several works related to the development of biosensors for gliadin detection are presented. Moreover, the use of electronic tongues to detect gliadin or gluten is reviewed and further investigated in an attempt to explain the possible detection mechanism based on gliadin-lipid membranes interactions. The challenges, concerns, and potential application of these (bio)sensors are discussed. Finally, some future perspectives are included regarding the applicability of electronic tongue within this research field.

2016Book part

Open access

Electrochemical multi-sensors device coupled with heuristic or meta-heuristic selection algorithms for single-cultivar olive oil classification

Publication . Peres, António M.; Veloso, Ana C.A.; Pereira, J.A.; Dias, L.G.

Potentiometric electrochemical multi-sensors’ performance highly depends on the capability of selecting the best set of sensors. Indeed, signals are usually collinear resulting in over-fitted multivariate models with low predictive applicability. In this work, a comparative study was made to evaluate the predictive performance of classification models coupled with heuristic or metaheuristic variable selection algorithms. In this study, eleven single-cultivar extra virgin olive oils, from two crop years, were used. The results demonstrated that linear discriminant analysis with simulated annealing algorithm allowed selecting the best subset of sensors enabling 100% of correct cross-validation classifications, considering samples split by crop year.

2014Conference object

Open access