Comparison of the Structure of Polyelectrolyte Multilayer Films Exhibiting a Linear and an Exponential Growth Regime: An in Situ Atomic Force Microscopy Study

Lavalle, Ph.; Gergely, Csilla; Cuisinier, Frédéric; Decher, Gero; Schaaf, Pierre; Voegel, Jean‐Claude; Picart, Catherine

doi:10.1021/ma0119833

Cited by 495 publications

(615 citation statements)

References 27 publications

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“…Fig. S1 shows the exponential increase in thickness and mass with layer number, as expected for exponentially growing PLL/PGA multilayer films (41). The deposition of BMP 2 and TGFβ 1 on the underlying PLL layers results in an increase in both thickness and mass, which indicates the successful embedding of the negatively charged proteins within the film architecture.…”

Section: Resultssupporting

confidence: 56%

Active multilayered capsules for in vivo bone formation

Facca

Cortez

Mendoza-Palomares

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

117

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Interest in the development of new sources of transplantable materials for the treatment of injury or disease has led to the convergence of tissue engineering with stem cell technology. Bone and joint disorders are expected to benefit from this new technology because of the low self-regenerating capacity of bone matrix secreting cells. Herein, the differentiation of stem cells to bone cells using active multilayered capsules is presented. The capsules are composed of poly-L-glutamic acid and poly-L-lysine with active growth factors embedded into the multilayered film. The bone induction from these active capsules incubated with embryonic stem cells was demonstrated in vitro. Herein, we report the unique demonstration of a multilayered capsule-based delivery system for inducing bone formation in vivo. This strategy is an alternative approach for in vivo bone formation. Strategies using simple chemistry to control complex biological processes would be particularly powerful, as they make production of therapeutic materials simpler and more easily controlled.

show abstract

Section: Resultssupporting

confidence: 56%

Active multilayered capsules for in vivo bone formation

Facca

Cortez

Mendoza-Palomares

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

117

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“…the material adsorbed on the electrode increases more than linearly with the number of deposited layers. This nonlinear or exponential growth of the film was also observed previously in the formation of PLL/PGA films on other substrates [13,18,19] and in films comprising PLL or PGA, for example, PLL/hyaluronic acid [20] and PGA/poly(allylamine hydrochloride) [21] multilayer films. Previous studies on polyelectrolyte LbL multilayer films have demonstrated that the growth of the multilayer film is entropy driven and an endothermic complexation process of PLL/PGA corresponds to the exponential growth of the film [22].…”

Section: Pll/pga Multilayer Film Assemblysupporting

confidence: 82%

Biocompatible polypeptide microcapsules via templating mesoporous silica spheres

Yu¹,

Gentle²,

Lu³

2009

Journal of Colloid and Interface Science

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We reported the stepwise formation of biocompatible poly(L-lysine)/poly(Lglutamic acid) (PLL/PGA) multilayer films on mesoporous silica (MS) spheres via layer-by-layer (LbL) self-assembly technique. In-situ QCM revealed the nonlinear (exponential) growth of PLL/PGA multilayer films at both pH 5.5 and pH 7.0 conditions. ξ-potential measurements of the multilayer coated particles indicated that the multilayer surface is being charge-overcompensated in each adsorption step, thereby facilitating adsorption of the next oppositely charged polypeptide onto the MS spheres. Hollow polypeptide capsules could be obtained by subsequently removing silica cores. By using enzyme-preloaded MS spheres as capsule templates, a general approach was developed for encapsulating enzymes in biocompatible microcapsules with high loading and retained bioactivity. The loading amount for several enzymes with different sizes and their bioactivity after encapsulation were also reported.

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“…These positively charged substrates were used for polyelectrolyte deposition beginning with a polyanion (PSS in the present case). 25 LbL assembly of PSS/PAH on functionalized glass or SIF substrates was carried out manually. The substrates were immersed in a PSS solution for 20 min, followed by a wash in water for 5 min, and immersed again in the PAH solution for 20 min, followed a wash for 5 min.…”

Section: Methodsmentioning

confidence: 99%

“…[15][16][17][18][19] A detail understanding of the MEF and its distance dependence nature is vital for its potential application in biomedical sensing. [20][21][22] Layer-by-layer (LbL) assembly [23][24][25][26][27][28][29][30][31][32][33][34][35][36] is based on the sequential adsorption of polycations and polyanions from dilute aqueous solution onto a solid substrate as a consequence of the electrostatic interaction and complex formation between oppositely charged polyelectrolytes. Starting from a functionalized solid substrate, it is possible to adsorb a variety of charged species ranging from polyelectrolytes, nanoparticles, and ionic dyes to many biological agents such as viruses, proteins, and DNA.…”

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

2007

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In the past several years we have demonstrated the metal-enhanced fluorescence (MEF) and the significant changes in the photophysical properties of fluorophores in the presence of metallic nanostructures and nanoparticles. MEF is largely dependent on several factors, such as chemical nature, size, shape of the nanostructure, and its distance from the interrogating fluorophore. Herein, we elucidate the potential of layer-by-layer (LbL) assembly to understand the distance dependence nature of MEF from sulforhodamine B (SRB) assembled on the plasmonic nanostructured surfaces [in the form of Silver Islands films (SIFs)]. The varied proximity of fluorophores from the SIF surfaces was controlled by constructing different numbers of alternate layers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH). An anionic laser dye SRB could be electrostatically attached to the positively charged PAH layer. Orientation of the SRB probe molecule adsorbed in PSS/PAH-layered assembly was determined by polarized absorption spectroscopy. The observed tilt angle of the probe transition dipole moment with respect to the surface normal was 40°. Our results show that MEF is indeed distance-dependent. Accordingly, we observed a maximum of a ~6-fold increase in the fluorescence intensity from a monolayer of the SRB at a distance of ~9 nm from the metal-nanostructured surface, with the enhancement decreasing down to ~1.5-fold at about a 30 nm separation distance. Consistently, the minimum lifetimes were about 4-fold shorter than those on glass slides without silver, with the lifetimes being about nearly the same for 15 layers of the PSS/PAH assembly. The intensity-time decays were analyzed with a lifetime distribution model to underpin the distance effect on the metal-fluorophore interaction in the nanometric range. The present study provides improved understanding of the interaction between plasmonic nanostructures and fluorophores and, more importantly, their distance dependence nature, where we used a robust, easy, and inexpensive alternate electrostatic LbL assembly as a bottom-up nanofabrication technique to control the probe distance from the surface.

show abstract

Comparison of the Structure of Polyelectrolyte Multilayer Films Exhibiting a Linear and an Exponential Growth Regime: An in Situ Atomic Force Microscopy Study

Cited by 495 publications

References 27 publications

Active multilayered capsules for in vivo bone formation

Active multilayered capsules for in vivo bone formation

Biocompatible polypeptide microcapsules via templating mesoporous silica spheres

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

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