Nouveaux types d'électrodes modifiés pour la détection de métaux lourds et leur application dans le domaine pharmaceutique

Le but de cette thèse a été le développement de capteurs électrochimiques en flux, basés sur l'utilisation du feutre de graphite comme électrode de travail pour l'analyse pharmaceutique et environnementale du cuivre (II) et du zinc (II), deux métaux lourds essentiels pour l'homéostasie de l'organisme humain, mais toxiques en excès. Pour la détection des ions zinciques (II), une cellule d'analyse en flux, bien adaptée pour l'utilisation du feutre de graphite utilisé comme électrode de travail a été élaborée. Les conditions analytiques ont été optimisées et ont conduit à la détection du zinc (II) avec de bonnes sensibilités. Ces résultats montrent l'intérêt de réaliser en flux l'étape de pré-concentration pour augmenter la cinétique d'électrodéposition. Nous avons réalisé une étude complète sur une électrode en feutre de graphite modifiée par réduction d'un sel de diazonium, conduisant à la formation d'un film organique ayant une forte affinité pour les ions cuivriques. L'électrode modifiée combinée avec une étape de pré-concentration en flux permet la réalisation d'un capteur d'ions Cu2+ avec une grande sensibilité et une bonne sélectivité. Nous avons développé, aussi, un capteur électrochimique en flux pour l'analyse des traces d'ions cuivriques à l'aide d'une électrode en feutre de graphite modifiée avec un récepteur capable de complexer de façon sélective les ions de cuivre (II) dans des solutions aqueuses. Enfin, nous avons testé la détection électrochimique du cuivre (II) à l'aide d'électrodes modifiées bidimensionnelles, CPE et SPE. Les résultats préliminaires montrent une bonne capacité de ces électrodes pour la complexation et la détection des ions cuivriques (II).The scope of this thesis was the development of flow electrochemical sensors, based on the use of graphite felt as a working electrode for the pharmaceutical and environmental analysis of zinc (II) and copper (II) ions, two heavy metals essential for the homeostasis of the human organism, but toxic if found in excess. For the detection of zinc (II) ions, a custom made flow cell was developed, well suited for the use of a graphite felt as working electrode in anodic stripping voltammetry analyses. The analytical conditions were optimized, leading to the detection of zinc with good sensitivities. These results prove the capacity of the preconcentration in flow to increase the kinetics of electrodeposition. A complet study on a graphite felt electrode modified by reduction of a diazonium salt, resulting in the formation of an organic film with high affinity for copper (II) ions was performed. The modified electrode combined with a flow preconcentration step allowed the achievement of a Cu2+ sensor with high sensitivity and good selectivity. We developed, also, a flow electrochemical sensor, allowing the analysis of traces of copper (II) ions, using a graphite felt electrode modified with a ligand proved to be able to selectively complex the copper (II) in aqueous solutions. Finally, we tested the electrochemical detection of zinc (II) and copper (II) ions by using modified bi-dimensional electrodes, CPE and SPE. Preliminary results show a good capacity of these modified electrodes for the complexation and detection of the copper (II) ions

Nouveaux types d'électrodes modifiés pour la détection de métaux lourds et leur application dans le domaine pharmaceutique

Le but de cette thèse a été le développement de capteurs électrochimiques en flux, basés sur l'utilisation du feutre de graphite comme électrode de travail pour l'analyse pharmaceutique et environnementale du cuivre (II) et du zinc (II), deux métaux lourds essentiels pour l'homéostasie de l'organisme humain, mais toxiques en excès. Pour la détection des ions zinciques (II), une cellule d'analyse en flux, bien adaptée pour l'utilisation du feutre de graphite utilisé comme électrode de travail a été élaborée. Les conditions analytiques ont été optimisées et ont conduit à la détection du zinc (II) avec de bonnes sensibilités. Ces résultats montrent l'intérêt de réaliser en flux l'étape de pré-concentration pour augmenter la cinétique d'électrodéposition. Nous avons réalisé une étude complète sur une électrode en feutre de graphite modifiée par réduction d'un sel de diazonium, conduisant à la formation d'un film organique ayant une forte affinité pour les ions cuivriques. L'électrode modifiée combinée avec une étape de pré-concentration en flux permet la réalisation d'un capteur d'ions Cu2+ avec une grande sensibilité et une bonne sélectivité. Nous avons développé, aussi, un capteur électrochimique en flux pour l'analyse des traces d'ions cuivriques à l'aide d'une électrode en feutre de graphite modifiée avec un récepteur capable de complexer de façon sélective les ions de cuivre (II) dans des solutions aqueuses. Enfin, nous avons testé la détection électrochimique du cuivre (II) à l'aide d'électrodes modifiées bidimensionnelles, CPE et SPE. Les résultats préliminaires montrent une bonne capacité de ces électrodes pour la complexation et la détection des ions cuivriques (II).The scope of this thesis was the development of flow electrochemical sensors, based on the use of graphite felt as a working electrode for the pharmaceutical and environmental analysis of zinc (II) and copper (II) ions, two heavy metals essential for the homeostasis of the human organism, but toxic if found in excess. For the detection of zinc (II) ions, a custom made flow cell was developed, well suited for the use of a graphite felt as working electrode in anodic stripping voltammetry analyses. The analytical conditions were optimized, leading to the detection of zinc with good sensitivities. These results prove the capacity of the preconcentration in flow to increase the kinetics of electrodeposition. A complet study on a graphite felt electrode modified by reduction of a diazonium salt, resulting in the formation of an organic film with high affinity for copper (II) ions was performed. The modified electrode combined with a flow preconcentration step allowed the achievement of a Cu2+ sensor with high sensitivity and good selectivity. We developed, also, a flow electrochemical sensor, allowing the analysis of traces of copper (II) ions, using a graphite felt electrode modified with a ligand proved to be able to selectively complex the copper (II) in aqueous solutions. Finally, we tested the electrochemical detection of zinc (II) and copper (II) ions by using modified bi-dimensional electrodes, CPE and SPE. Preliminary results show a good capacity of these modified electrodes for the complexation and detection of the copper (II) ions.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF

Mineralogy and Speleogenesis of the Ice-Cave from Poiana Vârtop (Bihor Mountains, Romania)

The cave of Poiana Vârtop in the NW Bihor Mountains hosts the fourth largest underground perennial glacier in Romania with a volume estimated to 12,000 m 3 . The ice accumulated within the cave as a result of trapping of subzero winter air through its single entrance near the top of the cave. The speleothem mineralogy is dominated by calcite, with minor amounts of included aragonite. Crusts of carbonate-hydroxylapatite (associated with bat guano) and goethite (associated with pyrite in the host limestone) are found at a few locations. Based on structural observations, dye traces, and cave galleries orientations, it is inferred that the cave is part of a much larger hydrologic karst system that also includes the nearby Humpleu-Poienita cave network

Electrochemical Sensor Based on Molecularly Imprinted Polymer for the Detection of Cefalexin

In this study, a new electrochemical sensor was developed for the detection of cefalexin (CFX), based on the use of a molecularly imprinted polymer (MIP) obtained by electro‒polymerization in an aqueous medium of indole-3-acetic acid (I3AA) on a glassy carbon electrode (GCE) and on boron-doped diamond electrode (BDDE). The two different electrodes were used in order to assess how their structural differences and the difference in the potential applied during electrogeneration of the MIP translate to the performances of the MIP sensor. The quantification of CFX was performed by using the electrochemical signal of a redox probe before and after the rebinding of the template. The modified electrode was characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of different parameters on the fabrication of the sensor was tested, and the optimized method presented high selectivity and sensitivity. The MIP-based electrode presented a linear response for CFX concentration range of 10 to 1000 nM, and a limit of detection of 3.2 nM and 4.9 nM was obtained for the BDDE and the GCE, respectively. The activity of the sensor was successfully tested in the presence of some other cephalosporins and of other pharmaceutical compounds. The developed method was successfully applied to the detection of cefalexin from real environmental and pharmaceutical samples

Home-Based Robotic Upper Limbs Cardiac Telerehabilitation System

This article proposes a new, improved home-based cardiac telerehabilitation system enhanced by a robotic and Virtual Reality module for cardiac patients to be used in their rehabilitation program. In this study, a novel strategy was used to integrate existing equipment and applications with newly developed ones, with the aim of reducing the need for technical skills of patients using remote control. Patients with acute or chronic heart diseases require long-term, individualized rehabilitation in order to promote their motor recovery and maintain an active and independent lifestyle. This will be accomplished by creating a system for at-home cardiac telerehabilitation augmented by a VR and cobot systems, which can be used long-term at home by each individual patient. In the pre-feasibility study carried out on healthy volunteers familiar with software applications and robotic systems, we demonstrate that RoboTeleRehab could be technically feasible both hardware and software

An Overview of Healthcare Associated Infections and Their Detection Methods Caused by Pathogen Bacteria in Romania and Europe

Healthcare-associated infections can occur in different care units and can affect both patients and healthcare professionals. Bacteria represent the most common cause of nosocomial infections and, due to the excessive and irrational use of antibiotics, resistant organisms have appeared. The most important healthcare-associated infections are central line-associated bloodstream infections, catheter-associated urinary tract infections, surgical site, soft tissue infections, ventilator-associated pneumonia, hospital acquired pneumonia, and Clostridioides difficile colitis. In Europe, some hospitalized patients develop nosocomial infections that lead to increased costs and prolonged hospitalizations. Healthcare-associated infection prevalence in developed countries is lower than in low-income and middle-income countries such as Romania, an Eastern European country, where several factors contribute to the occurrence of many nosocomial infections, but official data show a low reporting rate. For the rapid identification of bacteria that can cause these infections, fast, sensitive, and specific methods are needed, and they should be cost-effective. Therefore, this review focuses on the current situation regarding healthcare-associated infections in Europe and Romania, with discussions regarding the causes and possible solutions. As a possible weapon in the fight against the healthcare-associated infections, the diagnosis methods and tests used to determine the bacteria involved in healthcare-associated infections are evaluated