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Projeto de investigação
Straightforward Synthesis of Multifunctional core-shell composites and their applications
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Effect of Graphene vs. Reduced Graphene Oxide in Gold Nanoparticles for Optical Biosensors
Publication . Carvalho, Ana P. G.; Alegria, Elisabete C. B. A.; Fantoni, Alessandro; Ferraria, Ana M.; Do Rego, Ana M. Botelho; Ribeiro, Ana P. C.; CTS - Centro de Tecnologia e Sistemas; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; MDPI - Multidisciplinary Digital Publishing Institute
Aiming to develop a nanoparticle-based optical biosensor using gold nanoparticles (AuNPs) synthesized using green methods and supported by carbon-based nanomaterials, we studied the role of carbon derivatives in promoting AuNPs localized surface plasmon resonance (LSPR), as well as their morphology, dispersion, and stability. Carbon derivatives are expected to work as immobi-lization platforms for AuNPs, improving their analytical performance. Gold nanoparticles (AuNPs) were prepared using an eco-friendly approach in a single step by reduction of HAuCl4·3H2O using phytochemicals (from tea) which act as both reducing and capping agents. UV–Vis spectroscopy, transmission electron microscopy (TEM), zeta potential (ζ-potential), and X-ray photoelectron spectroscopy (XPS) were used to characterize the AuNPs and nanocomposites. The addition of reduced graphene oxide (rGO) resulted in greater dispersion of AuNPs on the rGO surface compared with carbon-based nanomaterials used as a support. Differences in morphology due to the nature of the carbon support were observed and are discussed here. AuNPs/rGO seem to be the most promising candidates for the development of LSPR biosensors among the three composites we studied (AuNPs/G, AuNPs/GO, and AuNPs/rGO). Simulations based on the Mie scattering theory have been used to outline the effect of the phytochemicals on LSPR, showing that when the presence of the residuals is limited to the formation of a thin capping layer, the quality of the plasmonic resonance is not affected. A further discussion of the application framework is presented.
Hybrid Nanocomposites of Plasmonic Metal Nanostructures and 2D Nanomaterials for Improved Colorimetric Detection
Publication . Serafinelli, Caterina; Fantoni, Alessandro; Alegria, Elisabete C. B. A.; Vieira, Manuela; CTS - Centro de Tecnologia e Sistemas; DEE - Departamento de Engenharia Electrotécnica e de Computadores; DEE2010-A2 Electrónica; MDPI - Multidisciplinary Digital Publishing Institute
Plasmonic phenomena and materials have been extensively investigated for a long time and gained popularity in the last few years, finding in the design of the biosensors platforms promising applications offering devices with excellent performances. Hybrid systems composed of graphene, or other 2D materials, and plasmonic metal nanostructures present extraordinary optical properties originated from the synergic connection between plasmonic optical effects and the unusual physicochemical properties of 2D materials, thus improving their application in a broad range of fields. In this work, firstly, an overview of the structures and properties of 2D nanomaterials will be provided along with the physics of surface plasmon resonance and localized surface plasmon resonance. In the second part of the work, some examples of colorimetric biosensors exploiting the outstanding properties of hybrids nanocomposites will be presented. Finally, concluding perspectives on the actual status, challenges, and future directions in plasmonic sensing biosensing will be provided. Special emphasis will be given to how this technology can be used to support digitalization and virtualization in pandemic handling.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
PTDC/QUI-QIN/29778/2017