Percorrer por autor "Seguro, Isabel"
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- Authenticating honey origin from Natural Park of Montesinho: innovative electrochemical genosensor devices assembled in paper-based transducersPublication . Pereira, Eduarda; Morais, Stephanie L.; Seguro, Isabel; Silva, Nádia F. D.; Santos, Marlene; Pacheco, João G.; Delerue-Matos, Cristina; Barroso, M. FátimaThe Natural Park of Montesinho (NPM) has a diverse ecosystem that is home to countless species of trees and plants characteristic of this area, including Castanea sativa. The honey produced in this region is highly appreciated for its taste and nutritional value, but it also has a wide range of health benefits. The geographical origin of the honey is a very important aspect in assessing the quality and authentication of the final product. Currently, several approaches are being explored to determinethese parameters, among which deoxyribonucleic acid (DNA)-based methods stand out.
- Challenging invasive fungal infections: development of innovative electrochemical nanogenosensors to detect Candida spp.Publication . Castanheira, Michelle; Morais, Stephanie L.; Seguro, Isabel; Santos, Marlene; Lima, Luís; Pacheco, João; Barroso, M. FátimaDespite the considerable advances in the prevention and treatment of fungal infections, invasive fungus such as Candida spp., continues to be one of the major causes of morbidity and mortality. The Global Action Fund Infections reported that, annually, more than 300 million people are infected with fungal infection, from these, about 1.5 million ends up dying. Candida albicans is the most important fungal 66 opportunistic pathogen, it can cause superficial or invasive infections. Candida, often, causes superficial infections, per example in skin or mucous membranes with simple and effective treatment, however, also can break to the bloodstream and disseminate to internal organs. It has been observed among high-risk patients such as allogeneic stem-cell transplant recipients and with acute leukemia receiving highdose chemotherapy. These patients are at a heightened risk of developing infections due to the suppression of their immune system during the transplantation process. The diagnosis of systemic fungal infections persists as a problematic issue. Therefore, the development of more efficient, sensitive and specific methods for early diagnosis is need. In this study, an easy, rapid, and accurate detection methods for fungal infections in patients undergoing hematopoietic stem cell transplantation (HSCT) was designed. To address this challenge, it was developed an electrochemical nanogenosensor for the detection of Candida albicans.This nanogenosensor was assembled in an innovative low-cost electrochemical paper based analytical devices (ePAD). A sandwich hybridization reaction was used to enhaced the sensitivity of the electrochemical signal. Preliminary results demonstrated that using this nanogenosensors it was possible to detect Candida spp., in synthetic fungus sample. Despite these results, the optimization of the nanogenosensor in terms of quantifying Candida albicans is being carried out, which will be validated in future studies.The applicability in hospital environment relatively to sensitivity, accuracy, quickness response, challenges and opportunities will be discuss in future developments.
- Computational Modelling and Sustainable Synthesis of a Highly Selective Electrochemical MIP-Based Sensor for Citalopram DetectionPublication . Rebelo, Patrícia; Pacheco, João; Voroshylova, Iuliia V.; Seguro, Isabel; Cordeiro, Maria Natália D. S.; Delerue-Matos, CristinaA novel molecularly imprinted polymer (MIP) has been developed based on a simple and sustainable strategy for the selective determination of citalopram (CTL) using screen-printed carbon electrodes (SPCEs). The MIP layer was prepared by electrochemical in situ polymerization of the 3-amino-4 hydroxybenzoic acid (AHBA) functional monomer and CTL as a template molecule. To simulate the polymerization mixture and predict the most suitable ratio between the template and functional monomer, computational studies, namely molecular dynamics (MD) simulations, were carried out. During the experimental preparation process, essential parameters controlling the performance of the MIP sensor, including CTL:AHBA concentration, number of polymerization cycles, and square wave voltammetry (SWV) frequency were investigated and optimized. The electrochemical characteristics of the prepared MIP sensor were evaluated by both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Based on the optimal conditions, a linear electrochemical response of the sensor was obtained by SWV measurements from 0.1 to 1.25 µmol L−1 with a limit of detection (LOD) of 0.162 µmol L−1 (S/N = 3). Moreover, the MIP sensor revealed excellent CTL selectivity against very close analogues, as well as high imprinting factor of 22. Its applicability in spiked river water samples demonstrated its potential for adequate monitoring of CTL. This sensor offers a facile strategy to achieve portability while expressing a willingness to care for the environment
- Electrochemical magnetic nanoparticles and paper-based biosensors for plant honey DNA origin detection and authenticationPublication . Morais, Stephanie Lopes; Castanheira, Michelle; Seguro, Isabel; Santos, Marlene; Pacheco, João; Domingues, Valentina; Delerue-Matos, Cristina; Barroso, Maria Fátima; Santos, MarleneFood fraud remains an issue with significant environmental, health, and socioeconomic impacts for consumers and the food industry alike. Honey, known for its natural sweetness, rich nutritional value, and numerous health benefits, is among the most adulterated foods found in the global market. Common fraudulent practices include mislabelling the honey’s botanical origin, blending it with lower-quality honeys, processed sugars, or other substances. Moreover, as most of their beneficial properties are linked to honey’s botanical origin, it is important to assure the safety and quality of the honey. Nonetheless, with the increasing number of reports on tampered or adulterated products appearing, there is a pressing need to develop an analytical tool that can quickly, affordably, and reliably ensure the quality and safety of honeys. In this study, an innovative inkjetprinted gold electrode paper-based biosensing platform coupled with gold-coated magnetic nanoparticles (MNPs) was developed to detect the genomic DNA of two plant species from which honey can be produced: Castanea sativa and Erica arborea. Analyzing public database platforms, a DNA-target probe for both C. sativa and E. arborea were selected and designed. These sensors resulted from the DNA hybridization reaction between the two complementary probes specific to both plant species in a sandwich format. Their complementary probes were modified with an amine (NH2) group and a fluorescein isothiocyanate and cut in two to generate the enzymatic amplification of the electrochemical signal. The hybridization reaction was labeled with enzymes, enabling chronoamperometric measurement of peroxidase activity associated with the MNPs on the gold electrode surface. The developed biosensor was then successfully applied to detect C. sativa and E. arborea present in real plant samples and, hence, determine the botanic origin of the honeys. Therefore, these MNPs and paper-based biosensors are a viable and rapid tool to help authenticate the origin of honeys.
- Electropolymerized, Molecularly Imprinted Polymer on a Screen-Printed Electrode—A Simple, Fast, and Disposable Voltammetric Sensor for TrazodonePublication . Seguro, Isabel; Rebelo, Patrícia; Pacheco, João; Delerue-Matos, CristinaIn recent years, analytical chemistry has been facing new challenges, particularly in developing low-cost, green, and easy-to-reproduce methods. In this work, a simple, reproducible, and low-cost electrochemical (voltammetric) molecularly imprinted polymer (MIP) sensor was designed specifically for the detection of trazodone (TZD). Trazodone (TZD) is an antidepressant drug consumed worldwide since the 1970s. By combining electropolymerization (surface imprinting) with screen-printed electrodes (SPCEs), the sensor is easy to prepare, is environmentally friendly (uses small amounts of reagents), and can be used for in situ analysis through integration with small, portable devices. The MIP was obtained using cyclic voltammetry (CV), using 4-aminobenzoic acid (4-ABA) as the functional monomer in the presence of TZF molecules in 0.1 M HCl. Non-imprinted control was also constructed in the absence of TZD. Both polymers were characterized using CV, and TZD detection was performed with DPV using the oxidation of TZD. The polymerization conditions were studied and optimized. Comparing the TZD signal for MIP/SPCE and NIP/SPCE, an imprinting factor of 71 was estimated, indicating successful imprinting of the TZD molecules within the polymeric matrix. The analytical response was linear in the range of 5–80 µM, and an LOD of 1.6 µM was estimated. Selectivity was evaluated by testing the sensor for molecules with a similar structure to TZD, and the ability of MIP/SPCE to selectively bind to TZD was proven. The sensor was applied to spiked tap water samples and human serum with good recoveries and allowed for a fast analysis (around 30 min).
- A novel DNA-based electrochemical sensor for the detection of Candida speciesPublication . Castanheira, Michelle Shereen Alves; Morais, Stephanie; Seguro, Isabel; Pacheco, João; Lima, Luís; Santos, Marlene; Barroso, M. Fátima; Santos, MarleneThe frequency and prevalence of invasive fungal infections have increased, particularly among hospitalized patients with severe underlying illnesses and/or immunocompromised individuals [1,2]. The survival of these patients relies on the prompt identification of the infection and on the timely initiation of antifungal therapy, and yet standard laboratory testing may yield ambiguous results [3]. The diagnostic approaches for candidiasis include culture testing, serological assays, and histopathologic analysis of tissues; however, these methods may be time-consuming and can yield insensitivity or inaccuracies. The prevailing “gold standard” for identifying Candida spp. fungemia is blood culture. Nonetheless, this is considered insensitive, as it has been shown to be positive in fewer than half of individuals with chronic disseminated candidiasis [4]. Culture methods are time-intensive, with certain Candida species requiring up to a week for development, which is an intolerable delay before initiating fungemia treatment. The difficulties in diagnosing Candida infections highlight the necessity for efficient and rapid methods to detect and identify clinically relevant fungi in a microbiology laboratory. This work involves the development of an electrochemical DNA-based sensor for the rapid, simple, and precise detection of Candida spp. This sensor, self-assembled in an electronic paper device (ePAD), is based on the electrochemical detection of the hybridization reaction between two complementary singlestranded DNA sequences. Initial research indicated that this DNA-based sensor may identify Candida spp. in synthetic DNA samples. Notwithstanding these results, efforts are underway to enhance the sensor for measuring Candida albicans; this methodology will be corroborated by a further study. Future advancements will focus on application within a medical setting, encompassing sensitivity, accuracy, response time, challenges, and potential.