Browsing by Author "Moreira, Felismina"
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- Alzheimer's diagnosis beyond cerebrospinal fluid: Probe-Free Detection of Tau Proteins using MXene based redox systems and molecularly imprinted polymersPublication . Arjum, Ajith Mohan; Deshpande, Sudhaunsh; Dunlop, Tom; Norman, Beth; Oliviera, Daniela; Vulpe, Georgeta; Moreira, Felismina; Sharma, SanjivPhosphorylated Tau proteins are promising biomarkers for the diagnosis and prognosis of Alzheimer's disease. This study presents a novel voltametric sensor using a vanadium MXene polydopamine (VxPDA) redox active composite and a Tau-441-specific polyaniline molecularly imprinted polymer (PANI MIP) for the sensitive detection of Tau-441 in interstitial fluid (ISF) and plasma. The VxPDA/PANI MIP sensor demonstrates a broad detection range of 5 fg/mL to 5 ng/mL (122 aM/L to 122 pM/L) in ISF without the use of redox mediators, with a lower limit of detection (LOD) of 2.3 fg/mL (60 aM/L). Furthermore, a handheld device utilizing this technology successfully detects Tau-441 in artificial serum with high sensitivity (5 fg/mL to 150 fg/mL (122 aM/L to 366 aM/L)) and specificity within a clinically relevant range. The rapid detection time (∼32 min) and low cost (∼£20/device) of this sensor highlight its potential for minimally invasive, early AD diagnosis in clinical settings. This advancement aims to facilitate a transition away from invasive cerebrospinal fluid (CSF)-based diagnostic techniques for AD.
- Bioinspired host-tailored polymers based on molecular imprinting for cytokine assessmentPublication . Ferreira, Bianca; Correa-Duarte, Miguel; Marques, Arcelina; Moreira, Felismina; Martins, GabrielaMolecular imprinting undergone a substantial boost driven by the awareness of molecularly imprinted polymers (MIPs)-ligand recognition skills. In particular, the introduction of natural-based compounds like cyclodextrins into the structural scaffold of synthetic recognition elements attracted great importance as a novel route to design more friendly-environments for protein binding, while promoting higher selectivity features. Herein, carbon electrodes doped with platinum nanoparticles supported on multiwalled carbon nanotubes and functionalized with polyallylamine (MWCNTs-PAH/Pt) were electrochemically modified with an imprinted sensing layer of poly(β-cyclodextrin-pyrrole) (poly(β-CD-Py)) towards interleukin 6 (IL-6) monitoring. The analytical performance of the biosensor was evaluated by using Cyclic Voltammetry and Electrochemical Impedance Spectroscopy techniques. Along the assembly, experimental parameters like nanomaterial deposition, monomer-protein concentrations and template removal solutions were carefully optimized and discussed. Furthermore, the electrodeposited film was characterized in terms of composition, morphology and structure using scanning electron microscopy (SEM) and Raman spectroscopy. Under optimal conditions, the developed sensor was able to rebind IL-6 over a wide linear range [1 pg/mL – 100 ng/mL], displaying high sensitivity, quick electrochemical response, and specific binding of the target molecule. Overall, this work reported the relevance of using hostguest complexes directly embedded in polymeric chains to generate newly controlled electrochemical sensors holding great potential for protein biosensing.
- Ciprofloxacin-imprinted polymeric receptors as ionophores for potentiometric transductionPublication . Oliveira, Helena M. V.; Moreira, Felismina; Sales, GoretiA 3D-mirror synthetic receptor for ciprofloxacin host–guest interactions and potentiometric transduction is presented. The host cavity was shaped on a polymeric surface assembled with methacrylic acid or 2-vinyl pyridine monomers by radical polymerization. Molecularly imprinted particles were dispersed in 2-nitrophenyl octyl ether and entrapped in a poly(vinyl chloride) matrix. The sensors exhibited a near-Nernstian response in steady state evaluations. Slopes and detection limits ranged from 26.8 to 50.0mVdecade−1 and 1.0×10−5 to 2.7×10−5 mol L−1, respectively. Good selectivity was observed for trimethoprim, enrofloxacin, tetracycline, cysteine, galactose, hydroxylamine, creatinine, ammonium chloride, sucrose, glucose, sulphamerazine and sulfadiazine. The sensors were successfully applied to the determination of ciprofloxacin concentrations in fish and in pharmaceuticals. The method presented offered the advantages of simplicity, accuracy, applicability to colored and turbid samples and automation feasibility, as well as confirming the use of molecularly imprinted polymers as ionophores for organic ion recognition in potentiometric transduction.
- Colorimetric cellulose-based test strip for the rapid assessment of pathogens exposurePublication . Vlad, Anitei; Moreira, Felismina; Guerreiro, Joana(Introduction) Antibody testing plays a crucial role in identifying individuals previously infected with a specific pathogen. The role of antibody testing gained extreme importance, especially during the COVID-19 pandemic, as monitoring anti-SARS-CoV-2 antibodies provides vital epidemiological and clinical insights into the evolution of coronavirus disease and the stratification of immunized and asymptomatic populations. Therefore, access to a highly portable and user-friendly sensor for point-of-care detection of SARS-CoV-2 antibodies or others contributes to aid in the timely diagnosis of infections or immune responses, immunity monitoring to enable personalized treatments.
- Colorimetric Paper-Based Sensors against Cancer BiomarkersPublication . Carneiro, Mariana; Rodrigues, R. V.; Moreira, Felismina; Ferreira Sales, Maria GoretiCancer is a major cause of mortality and morbidity worldwide. Detection and quantification of cancer biomarkers plays a critical role in cancer early diagnosis, screening, and treatment. Clinicians, particularly in developing countries, deal with high costs and limited resources for diagnostic systems. Using low-cost substrates to develop sensor devices could be very helpful. The interest in paper-based sensors with colorimetric detection increased exponentially in the last decade as they meet the criteria for point-of-care (PoC) devices. Cellulose and different nanomaterials have been used as substrate and colorimetric probes, respectively, for these types of devices in their different designs as spot tests, lateral-flow assays, dipsticks, and microfluidic paper-based devices (μPADs), offering low-cost and disposable devices. However, the main challenge with these devices is their low sensitivity and lack of efficiency in performing quantitative measurements. This review includes an overview of the use of paper for the development of sensing devices focusing on colorimetric detection and their application to cancer biomarkers. We highlight recent works reporting the use of paper in the development of colorimetric sensors for cancer biomarkers, such as proteins, nucleic acids, and others. Finally, we discuss the main advantages of these types of devices and highlight their major pitfalls.
- Development of a biosensor for phosphorylated Tau 181 protein detection in Early-Stage Alzheimer’s diseasePublication . Schneider, Maria; Guillade, Lucía; Correa-Duarte, Miguel A.; Moreira, FelisminaAlzheimer's disease (AD) is the most common form of dementia in the elderly, and there are still no reliable methods for its early detection. Recently, the phosphorylated protein Tau181 (p-Tau181) was identified as a highly specific biomarker for AD. Therefore, in this work, a new strategy for the development of an electrochemical-based immunosensor for the detection of p-Tau181 is described. For this purpose, a carbon screen-printed electrode (C-SPE) was modified with platinum nanoparticles decorated with multi-walled carbon nanotubes (MWCNTs- PAH /Pt) to enable antibody binding. Scanning electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectroscopy were used to study the morphology and crystallinity of the nanomaterials. Cyclic voltammetry and square-wave voltammetry were performed to compare the electrochemical properties of these electrodes. Under optimal conditions, the developed immunosensor exhibited a linear range from 8.6 to 1100 pg/mL, and the detection limit was estimated to be 0.24 pg/mL. This device showed excellent reproducibility and stability with remarkable selectivity for p-Tau181 in serum samples. Overall, this device enables minimally invasive clinical evaluation of p-Tau181 level with high sensitivity through simple operation, which makes this device a promising tool for future point-of-care purposes that will contribute to the technological development of clinical diagnostics.
- Development of an electrochemical biosensor for an Alzheimer biomarker detection in Point-of-CarePublication . Mendes, Francisca; Sales, Goreti; Moreira, FelisminaAlzheimer's disease (AD) is the dominant dementia condition of our society with great social and economic impact. One of the major pathological changes is the formation of extracellular insoluble deposits of β-amyloid protein (Aβ) in plaques. Pathological changes are often accompanied by neuroinflammation, abnormal activity of the neural network, dysfunction, degeneration and loss of neurons. Moreover, there is no current test capable of providing accurate diagnosis of AD and, besides that there is no treatment of prevention available, only a way to delay its progression, so the early diagnosis is the key in present. Research activities targeting such possibility include the identification of biomarkers in several biological fluids that may turn out an important means to diagnosis within future, mostly if these are found in peripheral blood (avoiding more invasive procedures). Thus, the main goal of this proposal is to develop novel, low cost (bio)sensing-devices with an aptamer as a biorecognition element of AD biomarker detection, Aβ42, in point-of-care.
- Development of an electrochemical biosensor for Galectin-3 detection in point-of-carePublication . Cerqueira, Sofia M.V.; Fernandes, Rúben; Moreira, Felismina; Sales, Maria Goreti FerreiraThis research work aims the development and optimization of an electrochemical biosensor based on molecularly-imprinted polymers [MIPs], for monitoring a melanoma biomarker, Galectin-3 (Gal-3). As it is a multifunctional protein that plays an important role in different types of tumors including melanoma, and has shown good results as a potential biomarker in several areas, the construction of a biosensor for the detection of this protein would be a simple and quick strategy to support the treatment of this type of pathology. The target molecule was recognized by a MIP material, created on the electrode’s surface by electropolymerizing a mixture of analyte (Gal-3) and monomer (2-aminophenol). Then, the protein was removed from the polymeric material by oxalic acid treatment. This process formed a non-conductive polymer with recognition sites showing affinity for the Gal-3. The control of the surface modification was monitored by Raman spectroscopy and electroanalytical techniques, namely electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The analytical performance of the sensor was evaluated by EIS, by following the analytical response of standard solutions ranging from 0.5 ng/mL to 5000 ng/mL Gal-3 in spyked serum. In general, the biosensor displayed good analytical features, considering limit of detection, response time and reproducibility. Overall, this study resulted from the need to create a new strategy for monitoring melanoma through the creation of a cheaper, faster and sensitive device, which can be commercialized and thus integrate the entire process associated with the treatment and follow-up of this pathology.
- Development of colorimetric cellulose-based test-strip for the rapid detection of antibodies against SARS-CoV2 virusPublication . Correia, Bárbara P.; Sousa, Mariana P.; Sousa, Cristina E. A.; Mateus, Daniela; Sebastião, Ana Isabel; Cruz, Maria Teresa; Matos, Ana Miguel; Santos Pereira, Ana Cláudia; Moreira, FelisminaGiven the pandemic situation, there is an urgent need for an accurate test to monitor antibodies anti-SARS-CoV-2, providing crucial epidemiological and clinical information to monitor the evolution of coronavirus disease in 2019 (COVID-19) and to stratify the immunized and asymptomatic population. Therefore, this paper describes a new cellulosebased test strip for rapid and cost-efective quantitative detection of antibodies to SARS-CoV2 virus by colorimetric transduction. For this purpose, Whatman paper was chemically modifed with sodium metaperiodate to introduce aldehyde groups on its surface. Subsequently, the spike protein of the virus is covalently bound by forming an imine group. The chemical control of cellulose paper modifcation was evaluated by Fourier transform infrared spectroscopy, thermogravimetry and contact angle analysis. Colorimetric detection of the antibodies was performed by a conventional staining method using Ponceau S solution as the dye. Color analysis was performed after image acquisition with a smartphone using Image J software. The color intensity varied linearly with the logarithm of the anti-S concentration (from 10 ng/mL to 1 μg/mL) in 500-fold diluted serum samples when plotted against the green coordinate extracted from digital images. The test strip was selective in the presence of nucleocapsid antibodies, urea, glucose, and bovine serum albumin with less than 15% interference, and detection of antibodies in human serum was successfully performed. Overall, this is a simple and afordable design that can be readily used for mass Abstract Given the pandemic situation, there is an population screening and does not require sophisticated equipment or qualifed personnel
- Electrochemical Aptasensor for the Detection of the Key Virulence Factor YadA of Yersinia enterocoliticaPublication . Sande, Maria Georgina; Ferreira, Débora; Rodrigues, Joana; Melo, Luís; Linke, Dirk; Silva, Carla J.; Moreira, Felismina; Sales, Goreti; Rodrigues, LígiaNew point-of-care (POC) diagnosis of bacterial infections are imperative to overcome the deficiencies of conventional methods, such as culture and molecular methods. In this study, we identified new aptamers that bind to the virulence factor Yersinia adhesin A (YadA) of Yersinia enterocolitica using cell-systematic evolution of ligands by exponential enrichment (cell-SELEX). Escherichia coli expressing YadA on the cell surface was used as a target cell. After eight cycles of selection, the final aptamer pool was sequenced by high throughput sequencing using the Illumina Novaseq platform. The sequencing data, analyzed using the Geneious software, was aligned, filtered and demultiplexed to obtain the key nucleotides possibly involved in the target binding. The most promising aptamer candidate, Apt1, bound specifically to YadA with a dissociation constant (Kd) of 11 nM. Apt1 was used to develop a simple electrochemical biosensor with a two-step, label-free design towards the detection of YadA. The sensor surface modifications and its ability to bind successfully and stably to YadA were confirmed by cyclic voltammetry, impedance spectroscopy and square wave voltammetry. The biosensor enabled the detection of YadA in a linear range between 7.0 × 104 and 7.0 × 107 CFU mL−1 and showed a square correlation coefficient >0.99. The standard deviation and the limit of detection was ~2.5% and 7.0 × 104 CFU mL−1, respectively. Overall, the results suggest that this novel biosensor incorporating Apt1 can potentially be used as a sensitive POC detection system to aid the diagnosis of Y. enterocolitica infections. Furthermore, this simple yet innovative approach could be replicated to select aptamers for other (bacterial) targets and to develop the corresponding biosensors for their detection.
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