Percorrer por autor "Challouf, Yasmine Rim"
A mostrar 1 - 2 de 2
Resultados por página
Opções de ordenação
- Assessing the enhancement performance of a novel aptasensor for osteopontin detectionPublication . Challouf, Yasmine Rim; Peres, António M.; Meirinho, Sofia Gabriel; Kanoun, AlifaCancer diseases are associated with the presence of a wide range of protein biomarkers. Aptasensor arrays may enable early multiple-detection of these biomarkers which can make important improvements in the lives of cancer patients. Clinical researches suggest that osteopontin, an overexpressed protein by tumor cells may be used as a diagnostic biomarker for several types of cancer. In this perspective, the objective of this dissertation was to evaluate the performance of a previously selected aptamer (C10K7) to detect osteopontin using cyclic voltammetry. The electrochemical detection of osteopontin was assessed using different screen-printed gold electrodes with the selected aptamer immobilized, being determined the detection and quantification limits. The specificity of the DNA aptasensor to other proteins was also studied using thrombin, lysozyme and bovine serum albumin which were evaluated by a previous research as possible interferents. The preliminary work carried out showed that this new aptamer allowed achieving a detection limit of 1.3 nM and a quantification limit of 4.0 nM for osteopontin. Considering that the reported range of plasma osteopontin concentrations in patients with either metastatic or recurrent breast cancer is up to 290 ng/mL (~ 4.46 nM) which is higher than the detection and quantification limits found and which suggest that the proposed aptasensor could be applied in both osteopontin detection and quantification. On the other hand, with the studied aptamer, the detection and quantification limits were lower than those reported in the literature for cyclic voltammetry, which were of 2.6 nM for a DNA aptamer (designated as C10K2) and 3.7 nM for an RNA aptamer (called OPN-R3). The repeatability assays showed a coefficient of variation equal to 7% which demonstrate the closeness of the agreement between the results. The evaluation of the specificity of the DNA aptasensor towards osteopontin showed little or almost no interference to other proteins. However, the interference study showed that the C10K7 aptamer was more prone to interferences from lysozyme and bovine serum albumin than the C10K2 aptamer, previously studied by the research team but showed a lower interference from thrombin. These results highlight the promising capability of the new DNA aptamer (C10K7) to be used in the development of an electrochemical aptasensor for the osteopontin detection, which could be foreseen as a diagnosis and therapy monitoring tool. Nevertheless, these preliminary satisfactory results need to be further checked, namely by the evaluation of its performance for the detection of human osteopontin in biological fluids like blood or plasma.
- ECARMINPublication . Challouf, Yasmine Rim; Ramalhosa, ElsaEcarmin is the first Portuguese company specialized in producing different types and forms of red colorant based on carminic acid extracted from cochineal insects like the E120, namely the allergen-free E120 and the purified carminic acid. The present innovation compared to our competitors has two axes, namely: i) a Process Innovation where the process of production of the colorant will be ecofriendly and 100% Portuguese. It must be taken into consideration that the whole carmine colors in Europe are imported from Peru or Mexico, while Ecarmin will produce 100% Portuguese carmine colors based on European Standards from its raw material to the final product, and ii) a Product Innovation, where, among our products, we will produce for the first time in Europe an allergen-free E120 specially designed for food industries making this natural color safer and of better quality. The following report presents the business plan of Ecarmin, with a market study, a research and development part, and a financial plan.