The structure of poly( l -lysine) (PLL)/hyaluronan (HA) polyelectrolyte multilayers formed by electrostatic self-assembly is studied using confocal laser scanning microscopy, quartz crystal microbalance, and optical waveguide lightmode spectroscopy. These films exhibit an exponential growth regime where the thickness increases exponentially with number deposited layers, leading to micrometer thick films. Previously such a was suggested result from “in” “out” diffusion PLL chains through film...

The formation of a new kind biocompatible film based on poly(l-lysine) and hyaluronic acid (PLL/HA) by alternate deposition PLL HA was investigated. Optical waveguide lightmode spectroscopy, streaming potential measurements, atomic force microscopy, quartz crystal microbalance (QCM) were used to analyze the different aspects buildup process such as deposited mass after each polyelectrolyte adsorption, overall surface charge film, its morphology. As for "conventional" multilayer systems,...

The formation of polysaccharide films based on the alternate deposition chitosan (CHI) and hyaluronan (HA) was investigated by several techniques. multilayer buildup takes place in two stages: during first stage, surface is covered isolated islets that grow coalesce as construction goes on. After steps, a continuous film formed second stage process place. whole characterized an exponential increase mass thickness with number steps. This growth mechanism related to ability polycation diffuse...

We report here on the structural characterization of polyelectrolytes multilayer films formed by poly(l-glutamic acid) and poly(l-lysine) (PGA/PLL). The growth this system is compared to that poly(styrenesulfonate)/poly(allylamine hydrochloride) (PSS/PAH) multilayers means in situ atomic force microscopy (AFM) optical waveguide lightmode spectroscopy (OWLS). In contrary (PSS/PAH)i are growing linearly with number deposited layer pairs i, data evidenced (PGA/PLL)i characterized an exponential...

Poly(L-lysine)/hyaluronan (PLL/HA) films were chemically cross-linked with a water soluble carbodiimide (EDC) in combination N-hydroxysulfo-succinimide (NHS) to induce amide formation. Fourier transform infrared spectroscopy confirms the conversion of carboxylate and ammonium groups into bonds. Quartz crystal microbalance-dissipation reveals that cross linking reaction is accompanied by change viscoelastic properties leading more rigid films. After cross-linking reaction, both positively...

Two forms of RNA Polymerase IV (PolIVa/PolIVb) have been implicated in RNA-directed DNA methylation (RdDM) Arabidopsis . Prevailing models imply a distinct function for PolIVb by association Argonaute4 (AGO4) with the C-terminal domain (CTD) its largest subunit NRPD1b. Here we show that extended CTD NRPD1b-type proteins exhibits conserved Argonaute-binding capacity through WG/GW-rich region functionally distinguishes Pol IVb from IVa, and is essential RdDM. Site-specific mutagenesis...

Controlling the bulk and surface properties of materials is a real challenge for bioengineers working in fields biomaterials, tissue engineering biophysics. The layer-by-layer (LbL) deposition method, introduced 20 years ago, consists alternate adsorption polyelectrolytes that self-organize on material's surface, leading to formation polyelectrolyte multilayer (PEM) films.1 Because its simplicity versatility, procedure has led considerable developments biological applications within past 5...

Additive manufacturing (AM) allows the fabrication of customized bone scaffolds in terms shape, pore size, material type and mechanical properties. Combined with possibility to obtain a precise 3D image defects using computed tomography or magnetic resonance imaging, it is now possible manufacture implants for patient-specific regeneration. This paper reviews state-of-the-art different materials AM techniques used 3D-printed field tissue engineering. Their advantages drawbacks are...

Mechanical properties of model and natural gels have recently been demonstrated to play an important role in various cellular processes such as adhesion, proliferation, differentiation, besides events triggered by chemical ligands. Understanding the biomaterial/cell interface is particularly many tissue engineering applications implant surgery. One final goals would be control precisely at biomaterial surface guide regeneration. In this work, we investigate substrate mechanical effect on...

Two types of polyelectrolyte multilayer films have been reported in the literature. These are (i) whose mass and thickness increase linearly as number deposited bilayers increases (ii) that grow exponentially. We present a model for buildup exponentially growing allows discussion behavior them unified manner. This is based on diffusion both out whole film part chains at least one polyelectrolytes constituting multilayer. In short, brought into contact with solution able to diffuse film....

Beside chemical properties and topographical features, mechanical of gels have been recently demonstrated to play an important role in various cellular processes, including cell attachment, proliferation, differentiation. In this work, we used multilayer films made poly(L-lysine)/Hyaluronan (PLL/HA) controlled stiffness investigate the effects thin on skeletal muscle cells (C2C12 cells) Prior differentiation, need adhere proliferate growth medium. Stiff (E(0) > 320 kPa) promoted formation...

The short-term interactions of chondrosarcoma cells with polyelectrolyte multilayer films built up by the alternate adsorption poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA) was studied in presence absence serum. their interaction serum proteins were first characterized means optical waveguide lightmode spectroscopy, quartz crystal microbalance, zeta potential measurements. In a serum-containing medium, detachment forces measured micropipet technique about eight times smaller on...

Efficient delivery of growth or survival factors to cells is one the most important long-term challenges current cell-based tissue engineering strategies. The extracellular matrix acts as a reservoir for number through interactions with its components. In matrix, are protected against circulating proteases and locally concentrated. Thus, localized long-lasting matrix-bound recombinant human bone morphogenetic protein 2 (rhBMP-2) from biomaterial surface would mimic in vivo conditions...

Mechanical properties of polyelectrolyte multilayer films were studied by nanoindentation using the atomic force microscope (AFM). Force−distance measurements colloidal probe tips systematically obtained for supported poly(l-lysine) and hyaluronan that are suited to bio-application. Both native covalently cross-linked as a function increasing layer number, which increases film thickness. The effective Young's modulus perpendicular film, E⊥, was determined be thickness, cross-linking, sample...

ABSTRACT Infection of implanted materials by bacteria constitutes one the most serious complications following prosthetic surgery. In present study, we developed a new strategy based on insertion an antimicrobial peptide (defensin from Anopheles gambiae mosquitoes) into polyelectrolyte multilayer films built alternate deposition polyanions and polycations. Quartz crystal microbalance streaming potential measurements were used to follow step construction embedding defensin within films....

In a marine environment, specific proteins are secreted by mussels and used as bioglue to stick surface. These mussel present an unusual amino acid 3,4‐dihydroxyphenylalanine (known DOPA). The outstanding adhesive properties of these materials in the sea harsh conditions have been attributed presence catechol groups DOPA. Inspired structure composition proteins, dopamine‐modified hyaluronic (HA‐DN) prepared carbodiimide chemistry is form thin surface‐adherent dopamine films. This conjugate...