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Projeto de investigação
Printed and drawn flexible electronics based on cellulose nanocomposites
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Reusable and highly sensitive SERS immunoassay utilizing gold nanostars and a cellulose hydrogel-based platform
Publication . Oliveira, Maria João; Cunha, Inês; de Almeida, Miguel P.; Calmeiro, Tomás; Fortunato, Elvira; Martins, Rodrigo; Pereira, Luís; Byrne, Hugh J.; Pereira, Eulália; Águas, Hugo; Franco, Ricardo; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UCIBIO - Applied Molecular Biosciences Unit; DQ - Departamento de Química; RSC - Royal Society of Chemistry
The development of robust and sensitive point-of-care testing platforms is necessary to improve patient care and outcomes. Surface-enhanced Raman scattering (SERS)-based immunosensors are especially suited for this purpose. Here, we present a highly sensitive and selective SERS immunoassay, demonstrating for example the detection of horseradish peroxidase (HRP), in a sandwich format. The strength of our biosensor lies in merging: (i) SERS-immunotags based on gold nanostars, allowing exceptional intense SERS from attached Raman probes, covalent attachment of anti-HRP antibodies by a simple chemical method providing exceptional antigen binding activity; (ii) the ease of preparation of the capture platform from a regenerated cellulose-based hydrogel, a transparent material, ideal for microfluidics applications, with low background fluorescence and Raman signal, particularly suited for preserving high activity of the covalently bound anti-HRP antibodies. The sandwich complexes formed were characterised by atomic force microscopy, and by scanning electron microscopy coupled with electron diffraction spectroscopy; and (iii) the robustness of the simple Classical Least Squares method for SERS data analysis, resulting in superior discrimination of SERS signals from the background and much better data fitting, compared to the commonly used peak integral method. Our SERS immunoassay greatly improves the detection limits of traditional enzyme-linked immunosorbent assay approaches, and its performance is better or comparable to those of existing SERS-based immunosensors. Our approach successfully overcomes the main challenges of application at point-of-care, including increasing reproducibility, sensitivity, and specificity, associated with an environmentally friendly and robust design. Also, the proposed design withstands several cycles of regeneration, a feature absent in paper-SERS immunoassays and this opens the way for sensitive multiplexing applications on a microfluidic platform.
Uv-responsive screen-printed porous zno nanostructures on office paper for sustainable and foldable electronics
Publication . Ferreira, Sofia Henriques; Cunha, Inês; Pinto, Joana Vaz; Neto, Joana Pereira; Pereira, Luís; Fortunato, Elvira; Martins, Rodrigo; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; MDPI - Multidisciplinary Digital Publishing Institute
The fabrication of low-cost, flexible, and recyclable electronic devices has been the focus of many research groups, particularly for integration in wearable technology and the Internet of Things (IoT). In this work, porous zinc oxide (ZnO) nanostructures are incorporated as a UV sensing material into the composition of a sustainable water-based screen-printable ink composed of car-boxymethyl cellulose (CMC). The formulated ink is used to fabricate flexible and foldable UV sensors on ubiquitous office paper. The screen-printed CMC/ZnO UV sensors operate under low voltage (≤2 V) and reveal a stable response over several on/off cycles of UV light exposure. The devices reach a response current of 1.34 ± 0.15 mA and a rise and fall time of 8.2 ± 1.0 and 22.0 ± 2.3 s, respectively. The responsivity of the sensor is 432 ± 48 mA W−1, which is the highest value reported in the literature for ZnO-based UV sensors on paper substrates. The UV-responsive devices display impressive mechanical endurance under folding, showing a decrease in responsivity of only 21% after being folded 1000 times. Their low-voltage operation and extreme folding stability indicate a bright future for low-cost and sustainable flexible electronics, showing potential for low-power wearable applications and smart packaging.
Carbon-Yarn-Based Supercapacitors with In Situ Regenerated Cellulose Hydrogel for Sustainable Wearable Electronics
Publication . Carvalho, José Tiago; Cunha, Inês; Coelho, João; Fortunato, Elvira; Martins, Rodrigo; Pereira, Luís; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; ACS - American Chemical Society
Developing sustainable options for energy storage in textiles is needed to power future wearable "Internet of Things" (IoT) electronics. This process must consider disruptive alternatives that address questions of sustainability, reuse, repair, or even a second life application. Herein, we pair stretch-broken carbon fiber yarns (SBCFYs), as current collectors, and an in situ regenerated cellulose-based ionic hydrogel (RCIH), as an electrolyte, to fabricate 1D fiber-shaped supercapacitors (FSCs). The areal specific capacitance reaches 433.02 μF·cm-2at 5 μA·cm-2, while the specific energy density is 1.73 × 10-2μWh·cm-2. The maximum achieved specific power density is 5.33 × 10-1mW·cm-2at 1 mA·cm-2. The 1D FSCs possess a long-life cycle and 92% capacitance retention after 10 »000 consecutive voltammetry cycles, higher than similar ones using the reference PVA/H3PO4gel electrolyte. Additionally, the feasibility and reproducibility of the produced devices were demonstrated by connecting three devices in series and parallel, showing a small variation of the current density in flat and bent positions. An environmentally responsible approach was implemented by recovering the active materials from the 1D FSCs and reusing or recycling them without compromising the electrochemical performance, thus ensuring a circular economy path.
Healable Cellulose Iontronic Hydrogel Stickers for Sustainable Electronics on Paper
Publication . Cunha, Inês; Martins, Jorge; Gaspar, Diana; Bahubalindruni, Pydi Ganga; Fortunato, Elvira; Martins, Rodrigo; Pereira, Luís; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; Wiley
Novel nature-based engineered functional materials combined with sustainable and economically efficient processes are among the great challenges for the future of mankind. In this context, this work presents a new generation of versatile flexible and highly conformable regenerated cellulose hydrogel electrolytes with high ionic conductivity and self-healing ability, capable of being (re)used in electrical and electrochemical devices. They can be provided in the form of stickers and easily applied as gate dielectric onto flexible indium–gallium–zinc oxide transistors, decreasing the manufacturing complexity. Flexible and low-voltage (<2.5 V) circuits can be handwritten on-demand on paper transistors for patterning of conductive/resistive lines. This user-friendly and simplified manufacturing approach holds potential for fast production of low-cost, portable, disposable/recyclable, and low-power ion-controlled electronics on paper, making it attractive for application in sensors and concepts such as the “Internet-on-Things.”.
Foldable and Recyclable Iontronic Cellulose Nanopaper for Low-Power Paper Electronics
Publication . Cunha, Inês; Ferreira, Sofia Henriques; Martins, Jorge; Fortunato, Elvira; Gaspar, Diana; Martins, Rodrigo; Pereira, Luís; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; John Wiley and Sons Inc.
An increase in the demand for the next generation of “Internet-of-Things” (IoT) has motivated efforts to develop flexible and affordable smart electronic systems, in line with sustainable development and carbon neutrality. Cellulose holds the potential to fulfil such demands as a low-cost green material due to its abundant and renewable nature and tunable properties. Here, a cellulose-based ionic conductive substrate compatible with printing techniques that combines the mechanical robustness, thermal resistance and surface smoothness of cellulose nanofibrils nanopaper with the high capacitance of a regenerated cellulose hydrogel electrolyte, is reported. Fully screen-printed electrolyte-gated transistors and universal logic gates are demonstrated using the engineered ionic conductive nanopaper and zinc oxide nanoplates as the semiconductor layer. The devices exhibit low-voltage operation (<3 V), and remarkable mechanical endurance under outward folding due to the combination of the robustness of the nanopaper and the compliance of the semiconductor layer provided by the ZnO nanoplates. The printed devices and the ion-conductive nanopaper can be efficiently recycled to fabricate new devices, which is compatible with the circular economy concept.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
OE
Número da atribuição
SFRH/BD/126409/2016