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Projeto de investigação
Advanced Production and Intelligent Systems
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Ultrasound-assisted protein-enhanced graphene synthesis for rapid electrochemical antibody sensing
Publication . Cardoso, Ana R.; Suleimenova, A.; Alves, João Frederico; Frasco, Manuela F.; Barquinha, Pedro; Sales, M. Goreti F.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Elsevier
This study presents a novel method for the fabrication of graphene as a functional interface for electrochemical sensors. Graphene was synthesized by probe-assisted ultrasonic exfoliation of graphite stabilized by the SARS-CoV-2 spike (S) protein. In this dual-function approach, the S protein is used for both graphene stabilization and antibody recognition, simplifying the production of biosensors. The biosensor was fabricated by modifying a carbon working electrode with the stabilized graphene-S-protein complex. Electrochemical impedance spectroscopy revealed a linear detection range from 1.0 pg/mL to 10.0 ng/mL in diluted human serum, with a detection limit of 0.17 pg/mL. The high selectivity for the S protein was confirmed against the SARS-CoV-2 nucleocapsid protein. The device successfully analysed serum samples, demonstrating its practical application. These results emphasize a simple, innovative platform that integrates graphene synthesis and biosensor functionality. This approach not only ensures a sensitive and stable substrate for monitoring antibodies against SARS-CoV-2, but also offers an approach that can be extended to detect different antibodies, by selecting the stabilizing protein that binds to the intended antibody.
Hydrophobic Eutectogels for the Removal of Contaminants of Emerging Concern from Water
Publication . Gabirondo, Elena; Araújo, Joao M. M.; Pereiro, Ana B.; Tomé, Liliana C.; LAQV@REQUIMTE; DQ - Departamento de Química; Wiley | Wiley-VCH Verlag
Five hydrophobic eutectic solvents based on menthol and thymol were prepared and incorporated into a poly(ethylene glycol) diacrylate (PEGDA) network to form eutectogel membranes. The two most promising eutectogels were further optimized by adding ethyl hexylacrylate (HA) to the eutectogel formulation to improve the compatibility between the eutectic solvent and polymer network and to enhance the water resistance of the resulting membranes. Thermal analysis confirmed the successful formation and integration of eutectic solvents within the polymer network. Rheological studies demonstrated the rubber-like behavior of the prepared hydrophobic eutectogels, with menthol-based variants exhibiting superior mechanical properties. Finally, sorption experiments were conducted using the optimized octanoic acid:menthol PEGDA-HA eutectogel to evaluate its efficiency in removing various contaminants of emerging concern (CECs), including diclofenac, iopromide, cefazolin, bisphenol A, and dichlorophenol. The results revealed high sorption capacities for bisphenol A (3213 mg⋅kg−1) and dichlorophenol (2981 mg⋅kg−1), followed by diclofenac (1490 mg⋅kg−1), whereas minimal sorption capacities were observed for iopromide and cefazolin. Overall, this study demonstrates the potential of hydrophobic eutectogels as efficient and tunable materials for water purification, paving the way for their application in the environmental remediation of different emerging pollutants related to global change and human activities.
A dual-signal sensor based on molecularly imprinted photonic polydopamine for detection of the oxidative stress biomarker allantoin
Publication . Suleimenova, Akmaral; Marques, Ana C.; Frasco, Manuela F.; Fortunato, Elvira; Sales, M. Goreti F.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; International Society of Electrochemistry (ISE) | Elsevier
A novel biomimetic detection method is presented allocating two transducer principles in a molecularly imprinted polymer (MIP)-based sensor. The device was constructed on a transparent three-electrode system of conductive indium tin oxide (ITO) fabricated by laser direct writing on glass substrates. The sensing layer was prepared by electropolymerizing dopamine in the presence of allantoin, on colloidal silica particles that exhibited a structural color due to the short-range ordered structure. This opto-electrochemical dual-signal output was successfully developed for the detection of the oxidative stress biomarker allantoin. The analytical properties were evaluated by electrochemical impedance spectroscopy and reflectance analysis of the structural color. The sensor showed a linear response over a wide range of allantoin concentrations (0.1 nmol L−1 to 10000 nmol L−1) measured in synthetic urine. As expected, the lowest limit of detection in urine (0.012 nmol L−1) was achieved with the electrochemical signal. In addition, other urinary oxidative stress metabolites tested as interferents, namely uric acid and 8-hydroxy-2′-deoxyguanosine, had no effect on the dual-signal detection of allantoin. The biomimetic and cost-effective properties of the materials in combination with the improved analytical properties of opto-electrochemical detection provide a sensor platform with great potential for the screening of oxidative stress biomarkers in urinalysis.
Enhancing Mechanical Energy Absorption of Honeycomb and Triply Periodic Minimal Surface Lattice Structures Produced by Fused Deposition Modelling in Reusable Polymers
Publication . Bustihan, Alin; Botiz, Ioan; Branco, Ricardo; Martins, Rui F; DEMI - Departamento de Engenharia Mecânica e Industrial; UNIDEMI - Unidade de Investigação e Desenvolvimento em Engenharia Mecânica e Industrial; MDPI - Multidisciplinary Digital Publishing Institute
This study investigated the mechanical energy absorption properties of polymeric lattice structures fabricated using additive manufacturing. Existing studies have primarily focused on rigid or single-use materials, with limited attention given to flexible polymers and their behaviour under repeated compressive loading. Addressing this gap, the structures investigated in this study are manufactured using three flexible polymers-polyether block amide, thermoplastic polyurethane, and thermoplastic copolyester elastomer-to enhance the reusability performance. Two high-performance designs were analysed, namely honeycomb structures (inspired by pomelo peel and simply hexagonal arrangements) and 3D triply periodic minimal surface structure of the type FRD. The primary objective was to evaluate their energy absorption capacity and reusability using three repeated compression tests. These tests revealed that thermoplastic copolyester elastomer exhibited the highest energy absorption in initial impact conditions, but lower values for the following compressions. However, polyether block amide demonstrated superior reusability, maintaining a consistent energy absorption efficiency of 56.1% over multiple compression cycles. The study confirms that modifying triply periodic minimal surface structures along the z-axis enhances their absorption efficiency, with even-numbered z-parameter structures outperforming odd-numbered ones due to their complete cell structure. These findings highlight the critical role of structural geometry and material selection to optimise polymeric lattice structures for lightweight reusable energy absorption applications, such as automotive safety and impact protection.
Deep eutectic solvent flow electrodes for high-voltage desalination via flow electrode capacitive deionisation
Publication . Gabirondo, Elena; Saif, Hafiz M.; Alves, Vitor D.; Crespo, João G.; Tomé, Liliana C.; Pawlowski, Sylwin; LAQV@REQUIMTE; DQ - Departamento de Química; Instituto de Tecnologia Química e Biológica António Xavier (ITQB); Elsevier
This study pioneers the application of deep eutectic solvents (DES) as electrolytes in flow electrode capacitive deionisation (FCDI) desalination systems, providing a novel and improved alternative to aqueous flow electrodes. The deep eutectic solvent, choline chloride-urea (ChCl-U), was selected for its wide electrochemical stability window, allowing voltages exceeding 1.23 V, which is the limit for aqueous flow electrodes. The effect of water doping on the viscosity and performance of the DES flow electrodes was also investigated. Cyclic voltammetry confirmed the electrochemical stability, while rheological and electrochemical impedance spectroscopy revealed that the addition of water reduced the viscosity and enhanced the conductivity of ChCl-U, making it suitable for use as an electrolyte in FCDI. Desalination experiments were performed within a potential range of up to 2.2 V. The ChCl-U flow electrode, containing 20 wt% water and 10 wt% activated carbon, achieved the best balance between desalination efficiency (83 %), desalination rate (0.17 mg/cm2.min), and effluent quality. Furthermore, 1H NMR analysis confirmed the absence of traces of the deep eutectic solvent in the dilute stream. The results highlight the potential of DES flow electrodes to enhance desalination processes by enabling higher operational voltages and improved performance, thereby paving the way for more efficient FCDI desalination systems.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
LA/P/0112/2020