Plasma surface modification of polymers for sensor applications

Polymeric sensors play an increasingly important role in monitoring the environment we live in, providing relevant information for a host of applications. Among them, significant efforts have been made to fabricate polymeric sensors useful for healthcare-related application fields, such as the sensitive detection of biomolecules and cellular interfacing. Within the well-established field of biomedical polymeric sensors, surface modification and/or functionalization using plasma is just emerging as a technology to improve selectivity and sensitivity in the biodetection process. Treatments based on plasma irradiation of polymer surfaces, which have been traditionally applied for cleaning, etching, activating or cross-linking, are currently being used to induce the formation of electrocatalytic species able to promote the oxidation of, for example, bioanalytes and/or gas molecules harmful for human health. Here, we summarize the main advances in the utilization of plasma technologies for the fabrication of polymeric sensors for advanced biomedical applications (e.g. humidity, temperature, pH, neurotransmitter, and glucose sensors).Peer ReviewedPostprint (author's final draft

Poly(ionic liquid)s for Magnetic, Ionic, and Electrical Stimuli-Responsive Applications

Poly(ionic liquid)s (PILs) are a fascinating subclass of strong polyelectrolytes formed from polymerizable ionic liquids. As a result of their unique properties and counterion exchangeability, PILs can exhibit conformation structure or material property changes in response to external stimuli such as changes in pH/ionic environment, magnetic fields, and electric potentials. In Chapter 1, a comprehensive review of PILs design as well as their stimuli-responsive behavior is provided. Additional motivation for each dissertation chapter is also discussed. In Chapter 2, magnetically responsive PILs (MPILs) are developed from complexing paramagnetic salts with a random PIL copolymer containing a metal-coordinating co-monomer, acrylamide. A systematic spectroscopic investigation (FTIR, UV-Vis, Raman, XPS) was performed to analyze the influence of the acrylamide comonomer on the paramagnetic transition metal complex and its binding to the polymers. A preliminary investigation into its room temperature magnetic properties through AC susceptometry and magnetic attraction to handheld magnets is also provided. In Chapter 3, self-assembly of these random copolymers is induced through complexation with the surfactant sodium dodecyl sulfate to form magnetically responsive polyelectrolyte-surfactant micellular solutions and films. Micellular self-assembly is examined as a function of surfactant concentration through DLS and ZP measurements for both a cobalt-based MPIL and the corresponding non-magnetic PIL copolymer. Cryogenic transmission electron microscopy and FTIR characterizations provide additional insight into the self-assemble structure. Applied magnetic stimuli responsive is investigated of both the solution structures and drop-cast films, with and without the presence of weak (~0.6 T) magnetic fields, through optical microscopy, AFM, and GISAXS. Chapter 4 completes the investigation of select MPIL copolymers and their polyelectrolyte-surfactant complexes through a thorough vibrating sample magnetometry study as a function of magnetic field strength and temperature. Additional FTIR, DLS, ZP, SEM, and DSC characterizations provide insight into the observed magnetic behavior. In Chapter 5, an all-polyelectrolyte block copolymer comprised of a poly(ionic liquid) block and a weak tertiary amine polyelectrolyte block is synthesized and characterized through a Cu(0) mediated atom transfer radical polymerization. NMR and FTIR spectroscopies confirm the synthesis and provide insight into intermolecular interactions, specifically electrostatics and hydrogen bonding, of the novel block copolymer in dry and solution states. DLS measurements indicate the block copolymer exhibits an expanded network like structure in pure dimethyl sulfoxide solution that collapses on addition to potassium nitrate (KNO3) salt, demonstrating salt responsive behavior. Self-assembly of the block copolymer as a drop-cast film was analyzed with a new technique to PIL systems, namely, a hybrid AFM-IR characterization. The films exhibited different morphology depending on film thickness. Chapter 6 examines the electrical stimuli responsive nature of the block copolymer and its corresponding homopolymer in ionic electro active polymer actuator composites. Ionic liquid was combined with the homo- and block copolymer PILs to decrease glass transition temperature and increase ion conductivity. Key parameters for ionic actuation were investigated, including glass transition temperature (DSC), thermal stability (TGA), ion conductivity (EIS), chemical interactions (FTIR), Young’s modulus (AFM force curves), film morphology (AFM), and actuation behavior to small, applied voltage

Poly(ionic liquid)s for Magnetic, Ionic, and Electrical Stimuli-Responsive Applications

Poly(ionic liquid)s (PILs) are a fascinating subclass of strong polyelectrolytes formed from polymerizable ionic liquids. As a result of their unique properties and counterion exchangeability, PILs can exhibit conformation structure or material property changes in response to external stimuli such as changes in pH/ionic environment, magnetic fields, and electric potentials. In Chapter 1, a comprehensive review of PILs design as well as their stimuli-responsive behavior is provided. Additional motivation for each dissertation chapter is also discussed. In Chapter 2, magnetically responsive PILs (MPILs) are developed from complexing paramagnetic salts with a random PIL copolymer containing a metal-coordinating co-monomer, acrylamide. A systematic spectroscopic investigation (FTIR, UV-Vis, Raman, XPS) was performed to analyze the influence of the acrylamide comonomer on the paramagnetic transition metal complex and its binding to the polymers. A preliminary investigation into its room temperature magnetic properties through AC susceptometry and magnetic attraction to handheld magnets is also provided. In Chapter 3, self-assembly of these random copolymers is induced through complexation with the surfactant sodium dodecyl sulfate to form magnetically responsive polyelectrolyte-surfactant micellular solutions and films. Micellular self-assembly is examined as a function of surfactant concentration through DLS and ZP measurements for both a cobalt-based MPIL and the corresponding non-magnetic PIL copolymer. Cryogenic transmission electron microscopy and FTIR characterizations provide additional insight into the self-assemble structure. Applied magnetic stimuli responsive is investigated of both the solution structures and drop-cast films, with and without the presence of weak (~0.6 T) magnetic fields, through optical microscopy, AFM, and GISAXS. Chapter 4 completes the investigation of select MPIL copolymers and their polyelectrolyte-surfactant complexes through a thorough vibrating sample magnetometry study as a function of magnetic field strength and temperature. Additional FTIR, DLS, ZP, SEM, and DSC characterizations provide insight into the observed magnetic behavior. In Chapter 5, an all-polyelectrolyte block copolymer comprised of a poly(ionic liquid) block and a weak tertiary amine polyelectrolyte block is synthesized and characterized through a Cu(0) mediated atom transfer radical polymerization. NMR and FTIR spectroscopies confirm the synthesis and provide insight into intermolecular interactions, specifically electrostatics and hydrogen bonding, of the novel block copolymer in dry and solution states. DLS measurements indicate the block copolymer exhibits an expanded network like structure in pure dimethyl sulfoxide solution that collapses on addition to potassium nitrate (KNO3) salt, demonstrating salt responsive behavior. Self-assembly of the block copolymer as a drop-cast film was analyzed with a new technique to PIL systems, namely, a hybrid AFM-IR characterization. The films exhibited different morphology depending on film thickness. Chapter 6 examines the electrical stimuli responsive nature of the block copolymer and its corresponding homopolymer in ionic electro active polymer actuator composites. Ionic liquid was combined with the homo- and block copolymer PILs to decrease glass transition temperature and increase ion conductivity. Key parameters for ionic actuation were investigated, including glass transition temperature (DSC), thermal stability (TGA), ion conductivity (EIS), chemical interactions (FTIR), Young’s modulus (AFM force curves), film morphology (AFM), and actuation behavior to small, applied voltage

New insights into the solid–liquid interface exploiting neutron reflectivity

We outline recent progress exploiting neutron reflectivity for structural and compositional investigations of the solid-liquid interface. There has been extensive activity in this area, with key areas of development: (i) an increased range of accessible substrates (e.g. metals and minerals), (ii) novel liquid phases, and (iii) strong themes in electrochemistry (e.g. batteries), corrosion, polymers and increasing application of extreme conditions

Novel Semi-Interpenetrated Polymer Networks of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)/Poly (Vinyl Alcohol) with Incorporated Conductive Polypyrrole Nanoparticles

[EN] This paper reports the preparation and characterization of semi-interpenetrating polymer networks (semi-IPN) of poly(3-hydroxybutirate-co-3-hydroxyvalerate), PHBV, and poly (vinyl alcohol), PVA, with conductive polypirrole (PPy) nanoparticles. Stable hybrid semi-IPN (PHBV/PVA 30/70 ratio) hydrogels were produced by solvent casting, dissolving each polymer in chloroform and 1-methyl-2-pyrrolidone respectively, and subsequent glutaraldehyde crosslinking of the PVA chains. The microstructure and physical properties of this novel polymeric system were analysed, including thermal behaviour and degradation, water sorption, wettability and electrical conductivity. The conductivity of these advanced networks rose significantly at higher PPy nanoparticles content. Fourier transform infrared spectroscopy (FTIR) and calorimetry characterization indicated good miscibility and compatibility between all the constituents, with no phase separation and strong interactions between phases. A single glass transition was observed between those of pure PHBV and PVA, although PVA was dominant in its contribution to the glass transition process. Incorporating PPy nanoparticles significantly reduced the hydrogel swelling, even at low concentrations, indicating molecular interactions between the PPy nanoparticles and the hydrogel matrix. The PHBV/PVA semi-IPN showed higher thermal stability than the neat polymers and PHBV/PVA blend, which also remained in the tertiary systems.This research was funded by the Spanish Ministry of Science, Innovation and Universities, grant number RTI2018-097862-B-C21, including the FEDER financial support, (awarded to R.S.i.S. and J.M.-M.) and by the Fundacion Universidad Catolica de Valencia San Vicente Martir, grant No 2019-231-003UCV (awarded to A.S.-A.). CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.Aparicio-Collado, JL.; Novoa, JJ.; Molina Mateo, J.; Torregrosa Cabanilles, C.; Serrano-Aroca, Á.; Sabater I Serra, R. (2021). Novel Semi-Interpenetrated Polymer Networks of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)/Poly (Vinyl Alcohol) with Incorporated Conductive Polypyrrole Nanoparticles. Polymers. 13(1):1-21. https://doi.org/10.3390/polym13010057S12113

Dynamic modeling and characterization of magnetic hybrid films of polyvinyl butyral/iron oxide nanoparticles (PVB/Fe₂O₃) devoted to microactuators.

This thesis was accomplished in a dual-degree modality between the consolidated group of Synthesis and Characterization of Materials ꟷFacultad de Ingeniería Mecánica y Eléctrica (FIME), Universidad Autónoma de Nuevo León (UANL), México, and the research group of Methodologies for Automatic Control and for Design of Mechatronic Systems (MACS), department of Automatic Control and Micro-Mechatronic Systems ꟷ FEMTO-ST institute, Université Bourgogne Franche-Comté (UBFC), France

Développement de substrats macromoléculaires utilisés pour des études de microscopie électrochimique à balayage

Le but de ce mémoire est de développer des substrats biologiques pour le Bio-SECM. Cette nouvelle méthode analytique est en émergence et elle est intéressante puisqu'elle permet des études électrochimiques appliquées aux systèmes biologiques, comme des cellules cancéreuses. Pour se faire, les cellules biologiques doivent être immobilisées sur des plastiques biocompatibles fonctionnalisés de façon à ce que les cellules soient disposées en ligne droite. En effet, si les cellules ont toujours la même disposition, la localisation par l'électrode est plus facile et rapide. Il s'agit donc d'un projet multidisciplinaire réunissant la biologie (culture cellulaire), la toxicologie et la chimie de surface. Afin de s'assurer de l'adhésion cellulaire, les surfaces de 2 plastiques, le Zeonor® 1060R et le polystyrène, sont modifiées par un traitement au plasma d'oxygène. Ceci permet l'ajout de groupements fonctionnels polaires contenant au moins un atome d'oxygène ce qui charge la surface et la rend hydrophile. Afin de vérifier si le traitement est efficace, des mesures d'AFM, de XPS et d'angles de contact sont effectuées. Ensuite, pour s'assurer de la biocompatibilité des surfaces, la vérification de l'état cellulaire est faite par microscopie à fluorescence en \ud utilisant 3 fluorophores: l'Alexa fluor 488 couplé à l'Annexin V (début d'apoptose), le Hoechst 33258 (apoptose avancée) et l'iodure de propidium (nécrose). Enfin, l'adhésion de cellules alignées est faite grâce à des méthodes de lithographie, soit la photolithographie et la lithographie molle. Ces procédés permettent d'obtenir un moule de PDMS contenant des canaux microfluidiques dans lesquels les cellules sont injectées. Les principaux résultats montrent que les deux plastiques peuvent devenir hydrophiles suite au traitement au plasma puisqu'ils présentent des groupements carboxyliques et hydroxyliques à leur surface. Aussi, ils sont biocompatibles et même si la division cellulaire semble plus efficace sur le polystyrène, le Zeonor permet de former des lignes de cellules pouvant servir aux analyses électrochimiques. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Cellules, Lithographie, Biocompatibilité, Fluorescence, Électrochimie

Taxonomy for engineered living materials

Engineered living materials (ELMs) are the most relevant contemporary revolution in materials science and engineering. These ELMs aim to outperform current examples of "smart", active or multifunctional materials, enabling countless industrial and societal applications. The "living" materials facilitate unique properties, including autonomy, intelligent responses, self-repair, and even self-replication. Within this dawning field, most reviews and documents have divided ELMs into biological ELMs, which are solely made of cells, and hybrid living materials, which consist of abiotic chassis and living cells. Considering that the most relevant feature of living material is that they are made of (or include) living cell colonies and microorganisms, we consider that ELMs should be classified and presented differently, more related to life taxonomies than materials science disciplines. Towards solving the current need for the classification of ELMs, this study presents the first complete proposal of taxonomy for these ELMs. Here, life taxonomies and materials classifications are hybridized hierarchically. Once the proposed taxonomy is explained, its applicability is illustrated by classifying several examples of biological ELMs and hybrid living materials, and its utility for guiding research in this field is analyzed. Finally, possible modifications and improvements are discussed, and a call for collaboration is launched for progressing in this complex and multidisciplinary field

HYDROGEL: RESPONSIVE STRUCTURES FOR DRUG DELIVERY

Hydrogels are water-swollen 3D networks made of polymers, proteins, small molecules, or colloids. They are porous in structure and entrap/encapsulate large amounts of therapeutic agents and biopharmaceuticals. Their unique properties like biocompatibility, biodegradability, sensitivity to various stimuli, and the ability to be easily conjugated with hydrophilic and hydrophobic drugs with a controlled-release profile make hydrogels a smart drug delivery system. Smart hydrogel systems with various chemically and structurally responsive moieties exhibit responsiveness to external stimuli including temperature, pH, ionic concentration, light, magnetic fields, electrical fields, and chemical and biological stimuli with selected triggers includes polymers with multiple responsive properties have also been developed elegantly combining two or more stimuli-responsive mechanisms. This article emphasized the types, features, and various stimuli systems that produce responsive delivery of drugs

Electrostimulated release of neutral drugs from polythiophene nanoparticles: smart regulation of drug-polymer interactions

Poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles are loaded with curcumin and piperine by in situ emulsion polymerization using dodecyl benzene sulfonic acid both as a stabilizer and a doping agent. The loaded drugs affect the morphology, size, and colloidal stability of the nanoparticles. Furthermore, kinetics studies of nonstimulated drug release have evidenced that polymer···drug interactions are stronger for curcumin than for piperine. This observation suggests that drug delivery systems based on combination of the former drug with PEDOT are much appropriated to show an externally tailored release profile. This is demonstrated by comparing the release profiles obtained in presence and absence of electrical stimulus. Results indicate that controlled and time-programmed release of curcumin is achieved in a physiological medium by applying a negative voltage of -1.25 V to loaded PEDOT nanoparticles.Peer ReviewedPostprint (author's final draft