Stretchable kirigami-inspired conductive polymers for strain sensors applications

RÉSUMÉ: Kirigami metamaterials can be exploited in stretchable electronics owing to their architecture, which can be leveraged to amplify stretchability, bendability and deformability. Herein, we report a stretchable kirigami-structured poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/polydimethylsiloxane (PDMS) polymer composite. The electromechanical response and mechanical behavior of kirigami PEDOT:PSS-coated PDMS and polymer composite specimens were investigated and compared with their non-kirigami counterparts. The kirigami structure exhibited improved electromechanical properties owing to its characteristic architecture. This study illustrates the application of a kirigami polymer composite as a strain sensor for human motion detection

Printable, adhesive, and self-healing dry epidermal electrodes based on PEDOT:PSS and polyurethane diol

ABSTRACT: Printable, self-healing, stretchable, and conductive materials have tremendous potential for the fabrication of advanced electronic devices. Poly(3,4-ethylenedioxithiopene) doped with polystyrene sulfonate (PEDOT:PSS) has been the focus of extensive research due to its tunable electrical and mechanical properties. Owing to its solution-processability and self-healing ability, PEDOT:PSS is an excellent candidate for developing printable inks. In this study, we developed printable, stretchable, dry, lightly adhesive, and self-healing materials for biomedical applications. Polyurethane diol (PUD), polyethylene glycol, and sorbitol were investigated as additives for PEDOT:PSS. In this study, we identified an optimal printable mixture obtained by adding PUD to PEDOT:PSS, which improved both the mechanical and electrical properties. PUD/PEDOT:PSS free-standing films with optimized composition showed a conductivity of approximately 30 S cm−1, stretchability of 30%, and Young's modulus of 15 MPa. A low resistance change (<20%) was achieved when the strain was increased to 30%. Excellent electrical stability under cyclic mechanical strain, biocompatibility, and 100% electrical self-healing were also observed. The potential biomedical applications of this mixture were demonstrated by fabricating a printed epidermal electrode on a stretchable silicone substrate. The PUD/PEDOT:PSS electrodes displayed a skin-electrode impedance similar to commercially available ones, and successfully captured physiological signals. This study contributes to the development of improved customization and enhanced mechanical durability of soft electronic materials

New Clathrin-Based Nanoplatforms for Magnetic Resonance Imaging

Background: Magnetic Resonance Imaging (MRI) has high spatial resolution, but low sensitivity for visualization of molecular targets in the central nervous system (CNS). Our goal was to develop a new MRI method with the potential for non-invasive molecular brain imaging. We herein introduce new bio-nanotechnology approaches for designing CNS contrast media based on the ubiquitous clathrin cell protein. Methodology/Principal Findings: The first approach utilizes three-legged clathrin triskelia modified to carry 81 gadolinium chelates. The second approach uses clathrin cages self-assembled from triskelia and designed to carry 432 gadolinium chelates. Clathrin triskelia and cages were characterized by size, structure, protein concentration, and chelate and gadolinium contents. Relaxivity was evaluated at 0.47 T. A series of studies were conducted to ascertain whether fluorescent-tagged clathrin nanoplatforms could cross the blood brain barriers (BBB) unaided following intranasal, intravenous, and intraperitoneal routes of administration. Clathrin nanoparticles can be constituted as triskelia (18.5 nm in size), and as cages assembled from them (55 nm). The mean chelate: clathrin heavy chain molar ratio was 27.0464.8: 1 fo

Global standards of Constitutional law : epistemology and methodology

Just as it led the philosophy of science to gravitate around scientific practice, the abandonment of all foundationalist aspirations has already begun making political philosophy into an attentive observer of the new ways in which constitutional law is practiced. Yet paradoxically, lawyers and legal scholars are not those who understand this the most clearly. Beyond analyzing the jurisprudence that has emerged from the expansion of constitutional justice, and taking into account the development of international and regional law, the ongoing globalization of constitutional law requires comparing the constitutional laws of individual nations. Following Waldron, the product of this new legal science can be considered as ius gentium. This legal science is not as well established as one might like to think. But it can be developed on the grounds of the practice that consists in ascertaining standards. As abstract types of best “practices” (and especially norms) of constitutional law from around the world, these are only a source of law in a substantive, not a formal, sense. They thus belong to what I should like to call a “second order legal positivity.” In this article I will undertake, both at a methodological and an epistemological level, the development of a model for ascertaining global standards of constitutional law

Stretchable Electrodes Using Conductive Polymers for the Detection of Vital Signs in Premature Infants

RÉSUMÉ: La surveillance des signes vitaux des enfants prématurés est d'une importance capitale pour leur santé. Les mesures de signaux électrophysiologiques nécessitent la mise en place d'électrodes sur la peau via un adhésif, ce qui peut entraîner des dommages car la peau des prématurés ne possède pas de couche externe protectrice. Par conséquent, des méthodes de surveillance alternatives sont nécessaires pour améliorer le confort et réduire le fardeau des prématurés. Cela peut être atteint avec des électrodes flexibles et étirables qui peuvent s'adapter à la forme et aux mouvements de l'enfant tout en maintenant la qualité du signal. À ce jour, quelques études ont été réalisées sur des électrodes à base d'hydrogel présentant d'excellentes propriétés mécaniques et électriques. Cependant, leur teneur en eau les rend sujettes à la dégradation par évaporation et donc inadéquates pour la surveillance à long terme. Ce mémoire s'est concentré sur le développement et la caractérisation d'un matériau sec, imprimable, étirable, légèrement adhésif et auto-guérissant qui convient aux électrodes biomédicales pour les nourrissons prématurés. Cette recherche s'est appuyée sur les caractéristiques favorables du poly(3,4-éthylènedioxithiopène) dopé au sulfonate de polystyrène (PEDOT:PSS), un matériau conducteur dont les propriétés électriques et mécaniques peuvent être modifiées en fonction des additifs qui y sont ajoutés. Dans ce travail, nous avons étudié l'incorporation du polyuréthane diol (PUD), du polyéthylène glycol (PEG) et du sorbitol au PEDOT:PSS afin de développer un mélange imprimable optimisé. Comme ces combinaisons améliorent considérablement les propriétés mécaniques et électriques du PEDOT:PSS, nous avons évalué ces propriétés à l'aide d'un testeur électromécanique. Nous avons également quantifié leur adhérence sur différentes surfaces afin d'évaluer leur compatibilité comme électrodes épidermiques. En outre, nous avons évalué la biocompatibilité du matériau afin de vérifier son innocuité pour une application cutanée. Nous avons également démontré les propriétés d'autoguérison électrique du PUD/PEDOT:PSS. ABSTRACT: Monitoring vital signs of prematurely born children is of utmost importance for their health. The measurements of electrophysiological signals require the placement of electrodes on the skin via an adhesive, which can cause damage as premature skin lacks a protective outer layer. Therefore, alternative monitoring methods are needed to increase comfort and reduce the burden on premature infants. This can be achieved with flexible and stretchable electrodes that can adapt to the shape and movements of the child while maintaining signal quality. To date, a few studies on hydrogel-based electrodes with excellent mechanical and electrical properties have been reported. However, their water content makes them prone to degradation from evaporation, and therefore unsuitable for long term monitoring. This study focused on the development and characterization of a dry, printable, stretchable, lightly adhesive, and self-healing material suitable for biomedical electrodes for premature infants. This research leveraged the favorable characteristics of poly(3,4-ethylenedioxithiopene) doped with polystyrene sulfonate (PEDOT:PSS), a conductive material with tunable electrical and mechanical properties depending on the used additives. In this work, we explored the incorporation of polyurethane diol (PUD), polyethylene glycol (PEG), and sorbitol as additives to PEDOT:PSS to develop an optimized printable mixture. As these combinations significantly enhance both the mechanical and electrical properties of PEDOT:PSS, we evaluated these properties on an electromechanical tester. We also quantified their adhesion on different substrates to evaluate their suitability for epidermal electrodes. Moreover, to verify the material’s safety for skin application, we assessed its biocompatibility. In addition, we demonstrated the full electrical self-healing properties of PUD/PEDOT:PSS. The potential biomedical application of this material was further demonstrated through the fabrication of a printed epidermal electrode on a stretchable silicone substrate. The resulting electrodes displayed skin-electrode impedance comparable to that of a commercially available alternative and successfully captured physiological signals, including electrocardiogram (ECG) and electromyogram (EMG) signals

La création d'un site internet sur le dysfonctionnement cranio-mandibulaire (Première partie)

LILLE2-UFR Odontologie (593502202) / SudocLILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF