Micro‐Nanostructured Interfaces Fabricated by the Use of Inorganic Block Copolymer Micellar Monolayers as Negative Resist for Electron‐Beam Lithography

Glass, Roman; Arnold, Marco; Blümmel, Jacques; Küller, Alexander; Möller, Martin; Spatz, Joachim P.

doi:10.1002/adfm.200304331

Cited by 162 publications

(129 citation statements)

References 29 publications

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“…The micelles were then loaded with a metal salt (H 2 PtCl 6· 6H 2 O) to produce self-confined and size-selected Pt nanoparticles. The particle size can be tuned by using polymers with different head lengths and/or by changing the metal-salt/polymer head concentration in the solution [24][25][26]. The solution was then mixed with TiO 2 in the form of a powder and placed in a tubular furnace open to the air for calcination.…”

Section: Methodsmentioning

confidence: 99%

Size Dependent Study of MeOH Decomposition Over Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation

et al. 2007

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We present here the size-dependent decomposition of methanol (MeOH) over narrowly distributed Pt nanoparticles supported on nanocrystalline anatase TiO 2 powder. Micelle encapsulation has been used to create Pt catalysts with average particle sizes of ~ 4, 6, and 8 nm. A packed bed mass flow reactor and mass spectrometry were employed to quantify the catalyst's activity and selectivity. Among the catalysts tested the smallest nanoparticles showed the best performance including an onset reaction temperature of ~145 °C. No byproducts such as CO 2 or CH 4 were observed in the test range of 100 to 330 °C.

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Section: Methodsmentioning

confidence: 99%

Size Dependent Study of MeOH Decomposition Over Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation

et al. 2007

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“…[21][22][23][24] Varying the molecular weight of diblock copolymers causes variations in lateral spacing between the gold nanoparticles. Here, we demonstrate that the lateral spacing of gold nanoparticles also depends on the concentration of the micellar dipcoating solution and on the substrate retraction velocity, the latter of which enables the formation of well-defined nanoparticle spacing gradients.…”

Section: Nih Public Accessmentioning

confidence: 99%

Induction of Cell Polarization and Migration by a Gradient of Nanoscale Variations in Adhesive Ligand Spacing

et al. 2008

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Cell interactions with adhesive surfaces play a vital role in the regulation of cell proliferation, viability and differentiation, and affect multiple biological processes. Since cell adhesion depends mainly on the nature and density of the adhesive ligand molecules, spatial molecular patterning, which enables the modulation of adhesion receptor clustering, might affect both the structural and signalling activities of the adhesive interaction. We herein show that cells plated on surfaces that present a molecularly defined spacing gradient of an integrin RGD ligand, can sense small but consistent differences in adhesive ligand spacing of about 1 nm across the cell diameter, which is approximately 61 m when the spacing includes 70 nm. Consequently, these positional cues induce cell polarization, and initiate cell migration and signalling. We propose that differential positional clustering of the integrin transmembrane receptors is used by cells for exploring and interpreting their environment, at high spatial sensitivity.Adhesion of tissue cells to the extracellular matrix depends on the activation of specific transmembrane receptors; e.g. integrins, which leads to the assembly of specialized adhesion sites known as focal adhesions (FA). 1 Activation and spatial organization of integrins are mainly controlled by epitopes containing a RGD (R = arginine, G = glycine, D = aspartate) sequence, that are present on a variety of adhesive extracellular matrix (ECM) proteins. Recent studies indicated that beyond the chemical specificity of the adhesive epitope, 2 many physical features of the adhesive surface, including its topography, 3 rigidity, 4 and precise epitope spacing, 5 are critical for guiding receptor-mediated adhesion formation and signalling. Specifically, it was demonstrated that cyclic RGDfK peptides linked to nanogold particles 6 which were arranged in pattern on substrates and interspaced by 58 or 73 nm, influence cell adhesion, 5 spreading, focal adhesion assembly, and migration 7,8 in very different ways. In these studies, control experiments demonstrated that only the specific functionalization of nanogold particles with cyclic RGD induced integrin clustering and such focal adhesion formation upon interaction with cells such as 3T3-fibroblasts or -* Corresponding author: spatz@mf.mpg.de. + Both authors contributed equally to this work. 19 On the molecular length scale, these methods enable quantification of an average molecular concentration, which gradually varies along the adhesive surface; however, they are too "noisy" to quantify the densities themselves, and density variations capable of inducing cell polarization. NIH Public AccessWe herein demonstrate a novel surface patterning technique for the generation of nanoparticle spacing gradients, which is based on controlled modulation of the selfassembly of diblock copolymer micelles. Due to the self-assembly of macromolecules, large-scale surface areas are easily processed by this technique. After successful biofunctionalization of the nano...

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“…The formation of gradients depends on hexagonal arrays of gold nanoparticles which were fabricated on the basis of block copolymer micellar self-assembly (Spatz et al, 2000Glass et al, 2003aGlass et al, , 2003b. By a modified dip-coating procedure we were able to vary the spacing between individual nanoparticles continuously in the range of several mm 2 on a single substrate with nanometer precision.…”

Section: Introductionmentioning

confidence: 97%

“…The general preparation method to form gold nanodot patterns (regular arrangement of gold nanodots) from diblock copolymer micellar solutions is described elsewhere (Spatz et al, 2000Glass et al, 2003aGlass et al, ,2003bHaupt et al, 2002Haupt et al, , 2003. For this study we used a polystyrene-block-poly[2-vinylpyridine-(HgoldCl 4 )] diblock copolymer (Polymer Source), consisting of a polystyrene block with in average 989 monomers and a poly [2-vinylpyridine] block with in average 385 monomer units.…”

Section: Preparation Of Gradient Surfacesmentioning

confidence: 99%

Cell adhesion and polarisation on molecularly defined spacing gradient surfaces of cyclic RGDfK peptide patches

Hirschfeld-Warneken¹,

Arnold

Cavalcanti-Adam

et al. 2008

European Journal of Cell Biology

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A combination of soluble and extracellular matrix (ECM)-immobilised molecular gradients steer cell migration and location in vivo. Here, gradients of ECM molecules are formed in vitro by the combination of a surface nanopatterning technique called block copolymer nanolithography (BCN) and a biofunctionalisation technique. A modified substrate dip coating process of BCN allows for the formation of precise molecular gradients of cyclic RGDfK peptide patches at interfaces which are presented to cells for testing cell adhesion and polarisation. Surfaces formed by BCN consist of hexagonally ordered gold dot patterns with a gradient in particle spacing. Each dot serves as a chemical anchor for the binding of cyclic RGDfK peptides which are specifically recognised by α v β 3 integrins. Due to steric hindrance only up to one integrin binds to one functionalised gold dot. Applying particle spacing gradients we demonstrate how cell morphology, adhesion area, actin and vinculin distribution as well as polarisation are influenced by the peptide patch spacing gradient. As a consequence, these gradients of adhesive ligands induce cell orientation towards smaller particle spacing when the gradient strength is 15 nm/mm at least. Eventually, this measures a minimal value of ligand patch spacing sensitivity of adhesive cells which is approximately 1 nm across the cell body.

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Micro‐Nanostructured Interfaces Fabricated by the Use of Inorganic Block Copolymer Micellar Monolayers as Negative Resist for Electron‐Beam Lithography

Cited by 162 publications

References 29 publications

Size Dependent Study of MeOH Decomposition Over Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation

Size Dependent Study of MeOH Decomposition Over Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation

Induction of Cell Polarization and Migration by a Gradient of Nanoscale Variations in Adhesive Ligand Spacing

Cell adhesion and polarisation on molecularly defined spacing gradient surfaces of cyclic RGDfK peptide patches

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