Polyelectrolyte multilayers for enhancing cell adhesion and potential applications in tissue engineering

Polyelectrolyte multilayers (PEMs) assembled by de Layer by Layer (LbL) technique offer multiplepossibilities for surface engineering as an alternative to covalent chemistry. PEMs have recently attractedattention as a mean to engineer scaffolds and implants to make their interface with tissue more amenablefor cell adhesion, migration and differentiation. In this review we will present the state of the art on theuse of polyelectrolyte multilayers for enhancing cell adhesion. In particular, we will show the differentapproaches followed in our group combining synthetic and bio polymers, and the use of thermalannealing.Fil: Muzzio, Nicolás Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Pasquale, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Moya, Sergio Eduardo. CIC biomaGUNE. Soft Matter Nanotechnology group; Españ

Polyelectrolyte multilayers for enhancing cell adhesion and potential applications in tissue engineering

Polyelectrolyte multilayers (PEMs) assembled by de Layer by Layer (LbL) technique offer multiplepossibilities for surface engineering as an alternative to covalent chemistry. PEMs have recently attractedattention as a mean to engineer scaffolds and implants to make their interface with tissue more amenablefor cell adhesion, migration and differentiation. In this review we will present the state of the art on theuse of polyelectrolyte multilayers for enhancing cell adhesion. In particular, we will show the differentapproaches followed in our group combining synthetic and bio polymers, and the use of thermalannealing.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

An efficient dynamical model of reluctance actuators with flux fringing and magnetic hysteresis

This paper presents an efficient and accurate dynamical model of reluctance actuators, suitable for prediction and control applications. It is a hybrid lumped-parameter state-space model that takes into account the mechanical and electromagnetic dynamics, including eddy currents, flux fringing, magnetic hysteresis and saturation. Special emphasis is placed on the hysteresis model, which is based on the Jiles–Atherton theory. The novel parts of the model – the gap reluctance expression and the modified Jiles–Atherton hysteresis model – are identified, showing that the simulated results fit very well the experimental data. Furthermore, its potential application for control is exemplified with a feedback strategy, in which the design of the controller and observer are based on the proposed dynamical model

Nonlinear Bounded State Estimation for Sensorless Control of an Electromagnetic Device

This paper presents a novel nonlinear state observer with discrete-time measurements for estimating the plunger position of linear travel solenoid valves. The observer is an unscented Kalman filter (UKF) for nonlinear systems that iteratively calculates an estimated mean and covariance of the state. It is based on a basic lumped parameter model, which contributes to the computational efficiency of the observer and facilitates its implementation. The magnetic reluctance is modeled taking into account the magnetic saturation and is partly defined by data obtained from finite element analysis (FEA). Boundary constraints are added to the estimated position to prevent it from surpassing its physical limits. Different tests performed with simulated and experimental data show that the estimations are accurate and robust to noise and model inaccuracies. Besides, although the observer has been developed for a specific device, the method can be easily extended to other electromechanical systems in which the position needs to be estimated

Tailored polyelectrolyte thin film multilayers to modulate cell adhesion

The layer-by-layer assembly of polyelectrolyte multilayers (PEMs) from natural or synthetic polyelectrolytes constitutes a very versatile and simple strategy to modify surfaces and modulate cell behavior. PEMs assembled from natural polyelectrolytes are very appealing for biological and medical applications due to their high biocompatibility. However, PEMs from natural polyelectrolytes display poor cell adhesion as they are soft materials with an elasticity modulus of a few kilopascal. In this report, the authors present results on the modulation of cell adhesion of different immortalized cell lines by PEMs. Two strategies are employed to vary cell adhesion: (1) a heterogeneous polyelectrolyte multilayer is assembled employing a rigid bottom block including a synthetic polyelectrolyte with a soft upper block of natural polyelectrolytes and (2) polyelectrolyte multilayers from natural polyelectrolytes are thermally annealed after assembly. The physicochemical characteristics of the PEMs change upon thermal treatment. Depending on the composition of the polyelectrolyte multilayer, cell adhesion may be enhanced or reduced. Based on the impact on PEM properties and cell adhesion caused by thermal annealing, a temperature gradient is applied to a PEM of poly-L-lysine/alginate to induce a spatial variation of PEM properties, resulting in a gradient in cell adhesion. The strategies shown here can be employed as simple alternatives to tailor PEM properties by means of fully biocompatible procedures.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Concepts for Designing Tailored Thin Film Surfaces with Potential Biological Applications

The tailoring of surfaces with nanostructured thin films, where interfacial properties can be controlled at the nanoscale, offers multiple possibilities for biological applications. The design of thin films with appropriate properties to induce desired biological responses at cell level requires the convergence of research from physics, chemistry, material science, biology, and medicine. Here, we will discuss the main surface properties that determine the behavior of isolated cells, cell colonies, and tissues interacting with a material. Surface roughness, morphological features, stiffness, wettability, chemical nature, and protein-surface interaction characteristics, as well as spatiotemporal heterogeneities, are expected to contribute to the desired biological performance of a material. A brief review in relation to thin films for biological applications will be presented. We will focus on examples in which basic rather simple processes play a key role in determining the triggering of a particular biological cell phenotype

Bimetallic ag-au nanoparticles inside mesoporous titania thin films: Synthesis by photoreduction and galvanic replacement, and catalytic activity

In this work, the synthesis and catalytic activity of bimetallic Ag–Au nanoparticles (NPs) supported in TiO2 mesoporous thin films (MTFs) are presented. The composite materials were obtained through a two-step procedure, performed at room conditions. In the first step, Ag NPs were grown inside the MTFs by photoreduction. Then, a galvanic replacement reaction with Au was carried out, yielding the bimetallic NPs. The composites were characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray reflectometry (XRR), which show that the alloyed Ag–Au NPs are present inside the mesopores. Moreover, Ag and Au composition relationship can be controlled by adjusting the reaction times of the photoreduction and galvanic replacement reactions, respectively. Pores remain accessible after NPs synthesis, a feature that ensures their possible applications in any device that requires the contact between the NPs and the medium. Catalytic activity of the composites towards 4-nitrophenol reduction by sodium borohydride was evaluated. Although all the bimetallic systems exhibit improved catalytic properties in comparison with the monometallic Ag composite, the sample with lower Au/Ag relationship is the most effective. For the first time, to the best of our knowledge, bimetallic Au–Ag NPs are encapsulated inside mesoporous TiO2 films, paving the way towards a wide variety of applications.Fil: Coneo Rodríguez, Rusbel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Troiani, Horacio Esteban. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Dispositivos y Sensores; ArgentinaFil: Moya, Sergio Eduardo. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina. CIC biomaGUNE; EspañaFil: Bruno, Mariano Martín. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Angelome, Paula Cecilia. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; Argentin

Enhanced antiadhesive properties of chitosan/hyaluronic acid polyelectrolyte multilayers driven by thermal annealing : Low adherence for mammalian cells and selective decrease in adhesion for Gram-positive bacteria

The development of antifouling coatings with restricted cell and bacteria adherence is fundamental for many biomedical applications. A strategy for the fabrication of antifouling coatings based on the layer-by-layer assembly and thermal annealing is presented. Polyelectrolyte multilayers (PEMs) assembled from chitosan and hyaluronic acid were thermally annealed in an oven at 37 °C for 72 h. The effect of annealing on the PEM properties and topography was studied by atomic force microscopy, ζ-potential, circular dichroism and contact angle measurements. Cell adherence on PEMs before and after annealing was evaluated by measuring the cell spreading area and aspect ratio for the A549 epithelial, BHK kidney fibroblast, C2C12 myoblast and MC-3T3-E1 osteoblast cell lines. Chitosan/hyaluronic acid PEMs show a low cell adherence that decreases with the thermal annealing, as observed from the reduction in the average cell spreading area and more rounded cell morphology. The adhesion of S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria strains was quantified by optical microscopy, counting the number of colony-forming units and measuring the light scattering of bacteria suspension after detachment from the PEM surface. A 20% decrease in bacteria adhesion was selectively observed in the S. aureus strain after annealing. The changes in mammalian cell and bacteria adhesion correlate with the changes in topography of the chitosan/hyaluronic PEMs from a rough fibrillar 3D structure to a smoother and planar surface after thermal annealing.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Tailored polyelectrolyte thin film multilayers to modulate cell adhesion

The layer-by-layer assembly of polyelectrolyte multilayers (PEMs) from natural or synthetic polyelectrolytes constitutes a very versatile and simple strategy to modify surfaces and modulate cell behavior. PEMs assembled from natural polyelectrolytes are very appealing for biological and medical applications due to their high biocompatibility. However, PEMs from natural polyelectrolytes display poor cell adhesion as they are soft materials with an elasticity modulus of a few kilopascal. In this report, the authors present results on the modulation of cell adhesion of different immortalized cell lines by PEMs. Two strategies are employed to vary cell adhesion: (1) a heterogeneous polyelectrolyte multilayer is assembled employing a rigid bottom block including a synthetic polyelectrolyte with a soft upper block of natural polyelectrolytes and (2) polyelectrolyte multilayers from natural polyelectrolytes are thermally annealed after assembly. The physicochemical characteristics of the PEMs change upon thermal treatment. Depending on the composition of the polyelectrolyte multilayer, cell adhesion may be enhanced or reduced. Based on the impact on PEM properties and cell adhesion caused by thermal annealing, a temperature gradient is applied to a PEM of poly-L-lysine/alginate to induce a spatial variation of PEM properties, resulting in a gradient in cell adhesion. The strategies shown here can be employed as simple alternatives to tailor PEM properties by means of fully biocompatible procedures.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

A New Biphasic Dicalcium Silicate Bone Cement Implant

This is the peer reviewed versión of the following article: "A New Biphasic Dicalcium Silicate Bone Cement Implant ", which has been published in final form at [doi:10.3390/ma10070758],. This article May be used for non-comercial pipotes in accordance with Wiley Terms an Conditions for Use of Self-Archived Versions.Odontologí