Future of Augmented Reality

Today virtual reality is very popular, but it is used mostly for entertainment. In future augmented reality referred to as the integration of digital information with the user's environment in real time will be the most popular thing in the world. Referring to these definitions, unlike virtual reality, which creates a totally artificial environment, augmented reality uses the existing environment and overlays new information on the top. By this way our life can become more interesting and informative. With the help of advanced AR technology (e.g. adding computer vision and object recognition) the information about the surrounding real world of the user becomes interactive and digitally manipulated information about the environment and its objects is overlaid in the real world

The role of the surface chemistry on the performance of graphene-based biosensors

L'analyse clinique bénéficie dans le monde entier d'une variété de tests diagnostiques. L'intérêt pour le développement de nouveaux tests cliniques résulte d’une part du besoin de détecter de nouveaux analytes tels que les virus et les biomarqueurs, ainsi que d’une forte demande pour la réduction des coûts, de la complexité et des temps d'analyse excessif des techniques actuelles. Parmi les nombreuses possibilités disponibles aujourd'hui, les dispositifs de type « point-of-care » (PoC) incorporant du graphène et ses dérivés sont des acteurs de premier plan. Ce travail vise à étudier et à comparer le potentiel de l'oxyde de graphène réduit (rGO) et du graphène formé par dépôt chimique en phase vapeur (CVD) pour les dispositifs PoC à transduction électrique et électrochimique. Le développement complet des biocapteurs, de la fabrication des transducteurs à base de graphène à la détection de molécules biologiques, est présenté. L'accent sera mis sur le choix des récepteurs greffés à la surface du graphène. Dans ce contexte, le greffage non-covalent de récepteurs utilisant différents ligands à base de pyrène ainsi que le greffage covalent via des sels de 4 - ((triisopropylsilyl) éthylényl) benzène diazonium seront démontrés et comparés. Les exemples de détection discutés sont basés sur la détection de la protéine de capside E7 du Papillomavirus humain (PVH) et sur le niveau de troponine cardiaque I (cTnI) associé aux maladies cardiovasculaires, dans différents échantillons biologiques.Mots clés: graphène, oxyde de graphène réduit, détection, électrochimie, transistors à base de graphène, chimie de surface.Clinical analysis benefits world-wide from a variety of diagnostic tests. The interest in the development of new clinical tests is not only driven by the demand to sense new analytes such as viruses and biomarkers, but also to reduce costs, complexity and lengthy analysis times of current techniques. Among the numerous of possibilities available today, point-of-care (PoC) devices incorporating graphene and its derivatives are prominent players. This work aims at investigating and comparing the potential of reduced graphene oxide (rGO) and graphene formed by chemical vapor deposition (CVD) for electrical and electrochemical based PoC devices. The full biosensor manufacturing process from manufacturing of the graphene-based transducers to sensing biological molecules is described. A focus will be on the choice of the surface receptors anchored onto graphene material. In this context, non-covalent receptor attachment using different pyrene-based ligands and the interest of covalent attachement via 4-((triisopropylsilyl)ethylenyl)benzene diazonium salts will be demonstrated and compared. Sensing examples discusses are based on the detection of the E7 capsid protein of the human papillomavirus (HPV) and the level of cardiac troponin I (cTnI), associated with cardiovascular diseases, in different biological samples.Keywords: graphene, reduced graphene oxide, sensing, electrochemistry, field effect transistors, surface chemistry

Le rôle de la chimie de surface sur la performance de biocapteurs à base de graphène

Clinical analysis benefits world-wide from a variety of diagnostic tests. The interest in the development of new clinical tests is not only driven by the demand to sense new analytes such as viruses and biomarkers, but also to reduce costs, complexity and lengthy analysis times of current techniques. Among the numerous of possibilities available today, point-of-care (PoC) devices incorporating graphene and its derivatives are prominent players. This work aims at investigating and comparing the potential of reduced graphene oxide (rGO) and graphene formed by chemical vapor deposition (CVD) for electrical and electrochemical based PoC devices. The full biosensor manufacturing process from manufacturing of the graphene-based transducers to sensing biological molecules is described. A focus will be on the choice of the surface receptors anchored onto graphene material. In this context, non-covalent receptor attachment using different pyrene-based ligands and the interest of covalent attachement via 4-((triisopropylsilyl)ethylenyl)benzene diazonium salts will be demonstrated and compared. Sensing examples discusses are based on the detection of the E7 capsid protein of the human papillomavirus (HPV) and the level of cardiac troponin I (cTnI), associated with cardiovascular diseases, in different biological samples.Keywords: graphene, reduced graphene oxide, sensing, electrochemistry, field effect transistors, surface chemistry.L'analyse clinique bénéficie dans le monde entier d'une variété de tests diagnostiques. L'intérêt pour le développement de nouveaux tests cliniques résulte d’une part du besoin de détecter de nouveaux analytes tels que les virus et les biomarqueurs, ainsi que d’une forte demande pour la réduction des coûts, de la complexité et des temps d'analyse excessif des techniques actuelles. Parmi les nombreuses possibilités disponibles aujourd'hui, les dispositifs de type « point-of-care » (PoC) incorporant du graphène et ses dérivés sont des acteurs de premier plan. Ce travail vise à étudier et à comparer le potentiel de l'oxyde de graphène réduit (rGO) et du graphène formé par dépôt chimique en phase vapeur (CVD) pour les dispositifs PoC à transduction électrique et électrochimique. Le développement complet des biocapteurs, de la fabrication des transducteurs à base de graphène à la détection de molécules biologiques, est présenté. L'accent sera mis sur le choix des récepteurs greffés à la surface du graphène. Dans ce contexte, le greffage non-covalent de récepteurs utilisant différents ligands à base de pyrène ainsi que le greffage covalent via des sels de 4 - ((triisopropylsilyl) éthylényl) benzène diazonium seront démontrés et comparés. Les exemples de détection discutés sont basés sur la détection de la protéine de capside E7 du Papillomavirus humain (PVH) et sur le niveau de troponine cardiaque I (cTnI) associé aux maladies cardiovasculaires, dans différents échantillons biologiques.Mots clés: graphène, oxyde de graphène réduit, détection, électrochimie, transistors à base de graphène, chimie de surface

Electrochemical cardiovascular platforms: Current state of the art and beyond

International audienc

“Click” Chemistry on Gold Electrodes Modified with Reduced Graphene Oxide by Electrophoretic Deposition

International audienceThe coating of electrical interfaces with reduced graphene oxide (rGO) films and their subsequent chemical modification are essential steps in the fabrication of graphene-based sensing platforms. In this work, electrophoretic deposition (EPD) of graphene oxide at 2.5 V for 300 s followed by vapor treatment were employed to coat gold electrodes uniformly with rGO. These interfaces showed excellent electron transfer characteristics for redox mediators such as ferrocene methanol and potassium ferrocyanide. Functional groups were integrated onto the Au/rGO electrodes by the electro-reduction of an aryldiazonium salt, 4-((triisopropylsilyl)ethylenyl)benzenediazonium tetrafluoroborate (TIPS-Eth-ArN) in our case. Chemical deprotection of the triisopropylsilyl function resulted in propargyl-terminated Au/rGO electrodes to which azidomethylferrocene was chemically linked using the Cu(I) catalyzed “click” chemistry

Enhanced electrocatalytic hydrogen evolution on a plasmonic electrode: the importance of the Ti/ TiO2 adhesion layer

The electrochemical production of hydrogen is enjoying renewed vigor due to its great promise as an environmentally friendly energy alternative. Herein, we demonstrate the capacity of nanoperforated gold films deposited on flexible substrates coated with nanometer thick Ti/TiO2 adhesion layers for electrochemical water splitting under light irradiation. The strong plasmonic induced electromagnetic field enhancement, which occurs under the illumination of plasmonic electrodes, facilitates the dissociation of water into hydrogen and improves the electrocatalytic hydrogen evolution activity beyond that of platinum. Under illumination at 980 nm at 2 W cm-2, a current density of -10 mA cm-2 was recorded at a low overpotential of h z -0.045 V (vs. RHE); under the same conditions, a Pt electrode achieved -10 mA cm-2 at h z -0.048 V (vs. RHE). Mechanistic investigations revealed that plasmon-excited perforated gold thin layers are an efficient source of hot electrons, contributing to their injection into the underlying TiO2-based adhesion layer. Direct electrochemical reduction of water appears to be a parallel reaction pathway to sustain the hydrogen evolution reaction on the interface. Both reaction pathways decrease the activation energy for the hydrogen evolution reaction similar to the benchmark Pt electrocatalyst

Gestión del agua en la jardinería pública y privada de la Región Metropolitana de Barcelona

El artículo examina la tipología y prácticas de riego en los jardines públicos y privados de la Region Metropolitana de Barcelona (RMB). El riego de jardines constituye un componente básico de los usos exteriores de agua en el sector doméstico y su expansión se vincula con el crecimiento reciente de la forma urbana dispersa en el territorio de la región. Se argumenta que el modelo urbano tiene una incidencia muy importante en la tipología y consumo de agua de los jardines. En la ciudad compacta, la jardinería pública es hegemónica y se caracteriza por una gestión relativamente eficiente aunque con predominio de especies poco adaptadas a la climatología mediterránea. En cambio, en la ciudad difusa, la jardinería privada sustituye a la pública y las prácticas de gestión dependen estrechamente del nivel de renta de los distintos usuarios

Controlled covalent functionalization of a graphene-channel of a field effect transistor as an ideal platform for (bio)sensing applications

International audienceThe controlled covalent functionalization of the graphene channel of a field effect transistor, based on interdigitated gold electrodes (source and drain), via electrochemical grafting, using specifically designed aryl diazonium species is demonstrated to allow the simple fabrication of a general platform for (bio)sensing applications. The electrochemical grafting of a protected ethynylphenyl diazonium salt leads to the deposition of only a monolayer on the graphene channel. This controlled covalent functionalization of the graphene channel results in a charge mobility of the GFET of 1739 ± 376 cm2 V−1 s−1 and 1698 ± 536 cm2 V−1 s−1 for the holes and electrons, respectively, allowing their utilization as (bio)sensors. After deprotection, a dense and compact ethynylphenyl monolayer is obtained and allows the immobilization of a wide range of (bio)molecules by a “click” chemistry coupling reaction (Huisgen 1,3-dipolar cycloaddition). This finding opens promising options for graphene-based (bio)sensing applications

Plasmon-Driven Electrochemical Methanol Oxidation on Gold Nanohole Electrodes

Direct methanol oxidation is expected to play a central role in low-polluting future power sources. However, the sluggish and complex electro-oxidation of methanol is one of the limiting factors for any practical application. To solve this issue, the use of plasmonic is considered as a promising way to accelerate the methanol oxidation reaction. In this study, we report on a novel approach for achieving enhanced methanol oxidation currents. Perforated gold thin film anodes were decorated with Pt/Ru via electrochemical deposition and investigated for their ability for plasmon-enhanced electrocatalytic methanol oxidation in alkaline media. The novel methanol oxidation anode (AuNHs/PtRu), combining the strong light absorption properties of a gold nanoholes array-based electrode (AuNHs) with surface-anchored bimetallic Pt/Ru nanostructures, known for their high activity toward methanol oxidation, proved to be highly efficient in converting methanol via the hot holes generated in the plasmonic electrode. Without light illumination, AuNHs/PtRu displayed a maximal current density of 13.7 mA/cm2 at −0.11 V vs Ag/AgCl. Enhancement to 17.2 mA/cm2 was achieved under 980 nm laser light illumination at a power density of 2 W/cm2. The thermal effect was negligible in this system, underlining a dominant plasmon process. Fast generation and injection of charge carriers were also evidenced by the abrupt change in the current density upon laser irradiation. The good stability of the interface over several cycles makes this system interesting for methanol electro-oxidation

[Review] The role of the surface ligand on the performance of electrochemical SARS-CoV-2 antigen biosensors

International audiencePoint-of-care (POC) technologies and testing programs hold great potential to significantly improve diagnosis and disease surveillance. POC tests have the intrinsic advantage of being able to be performed near the patient or treatment facility, owing to their portable character. With rapid results often in minutes, these diagnostic platforms have a high positive impact on disease management. POC tests are, in addition, advantageous in situations of a shortage of skilled personnel and restricted availability of laboratory-based analytics. While POC testing programs are widely considered in addressing health care challenges in low-income health systems, the ongoing pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections could largely benefit from fast, efficient, accurate, and cost-effective point-of-care testing (POCT) devices for limiting COVID-19 spreading. The unrestrained availability of SARS-CoV-2 POC tests is indeed one of the adequate means of better managing the COVID-19 outbreak. A large number of novel and innovative solutions to address this medical need have emerged over the last months. Here, we critically elaborate the role of the surface ligands in the design of biosensors to cope with the current viral outbreak situation. Their notable effect on electrical and electrochemical sensors' design will be discussed in some given examples