31 documents found, page 1 of 4
Nanoplasmonic Au:CuO thin films functionalized with APTES to enhance the sensit...
Proença, Manuela; Rodrigues, Marco S.; Moura, C.; Machado, A. V.; Borges, Joel; Vaz, FilipeCarbon monoxide (CO) is a highly flammable and toxic gas to humans and animals, that's why its detection and monitoring are crucial. A promising technique to develop a robust and cheap gas sensor, operating at room temperature, is Localized Surface Plasmon Resonance (LSPR) sensing. However, LSPR sensing of inorganic gas molecules, such as CO, is challenging due to their extremely small differences in refractive...
Functionalization of gutta-percha surfaces with argon and oxygen plasma treatme...
Ferreira, Inês; Lopes, Cláudia; Rodrigues, Marco S.; Rodrigues, Pedro António Veiga; Castro, Cidália; Braga, Ana Cristina; Lopes, Maria; Vaz, FilipeGutta-percha's lack of adhesion has been presented as a drawback to avoid gaps at sealer/gutta-percha interface. Plasma treatments have been scarcely assessed on gutta-percha surfaces as a method of enhancing adhesiveness. This study aimed to evaluate the effect of low-pressure Argon and Oxygen plasma atmospheres on conventional and bioceramic gutta-percha standardized smooth discs, assessing their roughness, s...
Immobilization of Streptavidin on a Plasmonic Au-TiO2 Thin Film towards an LSPR...
Pereira-Silva, Patrícia; Meira, Diana I.; Costa-Barbosa, Augusto; Costa, Diogo; Rodrigues, Marco S.; Borges, Joel; Machado, Ana V.; Cavaleiro, AlbanoOptical biosensors based on localized surface plasmon resonance (LSPR) are the future of label-free detection methods. This work reports the development of plasmonic thin films, containing Au nanoparticles dispersed in a TiO2 matrix, as platforms for LSPR biosensors. Post-deposition treatments were employed, namely annealing at 400 °C, to develop an LSPR band, and Ar plasma, to improve the sensitivity of the Au...
Optimization of Au:CuO thin films by plasma surface modification for high-resol...
Proença, Manuela; Rodrigues, Marco S.; Meira, Diana I.; Castro, M. Cidalia R.; Rodrigues, Pedro V.; Machado, A. V.; Alves, Eduardo; Barradas, Nuno P.In this study, thin films composed of gold nanoparticles embedded in a copper oxide matrix (Au:CuO), manifesting Localized Surface Plasmon Resonance (LSPR) behavior, were produced by reactive DC magnetron sputtering and post-deposition in-air annealing. The effect of low-power Ar plasma etching on the surface properties of the plasmonic thin films was studied, envisaging its optimization as gas sensors. Thus, t...
Chitosan micro-membranes with integrated gold nanoparticles as an LSPR-based se...
Meira, Diana Isabela Faria; Proença, Maria Manuela Carvalho; Rebelo, Rita Daniela Nogueira; Barbosa, Ana Isabel Ferreira; Rodrigues, Marco S.Currently, there is an increasing need to develop highly sensitive plasmonic sensors able to provide good biocompatibility, flexibility, and optical stability to detect low levels of analytes in biological media. In this study, gold nanoparticles (Au NPs) were dispersed into chitosan membranes by spin coating. It has been demonstrated that these membranes are particularly stable and can be successfully employed...
Plasmonic strain sensors based on Au-TiO2 thin films on flexible substrates
Rodrigues, Marco S.; Borges, Joel; Vaz, F.This study aimed at introducing thin films exhibiting the localized surface plasmon resonance (LSPR) phenomenon with a reversible optical response to repeated uniaxial strain. The sensing platform was prepared by growing gold (Au) nanoparticles throughout a titanium dioxide dielectric matrix. The thin films were deposited on transparent polymeric substrates, using reactive magnetron sputtering, followed by a lo...
Immobilization of streptavidin on a plasmonic Au-TiO2 thin film towards an LSPR...
Pereira-Silva, Patrícia; Meira, Diana I.; Costa-Barbosa, Augusto; Costa, Diogo; Rodrigues, Marco S.; Borges, Joel; Machado, Ana V.; Cavaleiro, AlbanoOptical biosensors based on localized surface plasmon resonance (LSPR) are the future of label-free detection methods. This work reports the development of plasmonic thin films, containing Au nanoparticles dispersed in a TiO<sub>2</sub> matrix, as platforms for LSPR biosensors. Post-deposition treatments were employed, namely annealing at 400 °C, to develop an LSPR band, and Ar plasma, to improve the sensitivit...
Gas sensors based on localized surface plasmon resonances: synthesis of oxide f...
Rodrigues, Marco S.; Borges, Joel; Lopes, Cláudia Jesus Ribeiro; Pereira, Rui M. S.; Vasilevskiy, Mikhail; Vaz, F.This work presents a comprehensive review on gas sensors based on localized surface plasmon resonance (LSPR) phenomenon, including the theory of LSPR, the synthesis of nanoparticle-embedded oxide thin films, and strategies to enhance the sensitivity of these optical sensors, supported by simulations of the electromagnetic properties. The LSPR phenomenon is known to be responsible for the unique colour effects o...
Me-Doped Ti–Me intermetallic thin films used for dry biopotential electrodes: a...
Lopes, Cláudia Jesus Ribeiro; Fiedler, Patrique; Rodrigues, Marco S.; Borges, Joel; Bertollo, Maurizio; Alves, Eduardo; Barradas, Nuno PessoaIn a new era for digital health, dry electrodes for biopotential measurement enable the monitoring of essential vital functions outside of specialized healthcare centers. In this paper, a new type of nanostructured titanium-based thin film is proposed, revealing improved biopotential sensing performance and overcoming several of the limitations of conventional gel-based electrodes such as reusability, durabilit...
Thin films of Au-Al2O3 for plasmonic sensing
Meira, Diana Isabela Faria; Domingues, Rui P.; Rodrigues, Marco S.; Alves, Eduardo; Barradas, Nuno P.; Borges, Joel Nuno Pinto; Vaz, F.This works reports on the development of nanoplasmonic thin films, composed of Au nanoparticles embedded in an Al2O3 matrix. The Au-Al2O3 thin films were deposited by magnetron sputtering, and then subjected to thermal treatments (in-air) to promote the growth of the Au nanoparticles. The change of the number of gold pellets placed in the erosion zone of the aluminium target, originated Au concentrations in the...