Polarization nano-tomography of tightly focused light landscapes by self-assembled monolayers.

Recently, four-dimensional (4D) functional nano-materials have attracted considerable attention due to their impact in cutting-edge fields such as nano-(opto)electronics, -biotechnology or -biomedicine. Prominent optical functionalizations, representing the fourth dimension, require precisely tailored light fields for its optimal implementation. These fields need to be like-wise 4D, i.

Functionalization and Patterning of Self-Assembled Monolayers and Polymer Brushes Using Microcontact Chemistry.

Because the surface connects a material to its environment, the functionalization, modification, and patterning of surfaces is key to a wide range of materials applied in microelectronics, displays, sensing, microarrays, photovoltaics, catalysis, and other fields. Self-assembled monolayers (SAMs), which can be deposited on a wide range of inorganic materials, are only a few nanometers thick, yet they can radically change the properties of the resulting interface. Alternatively, thin polymer films composed of polymer brushes grown from the surface provide a more robust molecular modification of inorganic materials.

Functionalization of Clinically Approved MRI Contrast Agents for the Delivery of VEGF.

In combining the two clinically approved substances ferumoxytol and VEGF-165 via peptide coupling, we propose a straightforward approach to obtain a potentially ready-to-use theranostic contrast agent for specific cardiovascular diseases. Clinical and preclinical magnetic resonance imaging (MRI) studies have shown that intravenously applied superparamagnetic ferumoxytol nanoparticles accumulate in acute ischemic myocardial tissue. On the other hand, growth factors such as VEGF-165 (vascular endothelial growth factor) play a major role during angiogenesis and vasculogenesis.

N-Heterocyclic Carbene-Modified Au-Pd Alloy Nanoparticles and Their Application as Biomimetic and Heterogeneous Catalysts.

The preparation of water-soluble, N-heterocyclic-carbene-stabilized Au-Pd alloy nanoparticles by a straightforward ligand exchange process is presented. Extensive analysis revealed excellent size retention and stability over years in water. The alloy nanoparticles were applied as biomimetic catalysts for aerobic oxidation of d-glucose, for which monometallic Au and Pd nanoparticles showed no or negligible activity.

Metal vapor synthesis of ultrasmall Pd nanoparticles functionalized with N-heterocyclic carbenes.

The synthesis of N-heterocyclic carbene (NHC)-stabilized palladium nanoparticles (PdNPs) by an entirely new strategy comprising the NHC functionalization of ligand-free PdNPs obtained by metal vapor synthesis is described. Detailed characterization confirms the formation of very small monodisperse PdNPs (2.3 nm) and the presence of the NHC ligand on the Pd surface.

Versatile Micropatterns of N-Heterocyclic Carbenes on Gold Surfaces: Increased Thermal and Pattern Stability with Enhanced Conductivity.

Patterned monolayers of N-heterocyclic carbenes (NHCs) on gold surfaces were obtained by microcontact printing of NHC-CO adducts and NHC(H)[HCO ] salts. The NHC-modified areas showed an increased conductivity compared to unmodified gold surface areas. Furthermore, the remaining surface areas could be modified with a second, azide-functionalized carbene, facilitating further applications and post-printing modifications.

Solid state electrochemiluminescence from homogeneous and patterned monolayers of bifunctional spirobifluorene.

Electrochemiluminescence (ECL) generated by a monolayer of a spirobifluorene derivative covalently bound onto an indium tin oxide (ITO) substrate is reported for the first time. Our approach allows the efficient preparation homogeneous and patterned substrates through micromolding in capillaries (MIMIC), and opens novel scenarios for multicolour ECL applications.

Covalent Immobilization of (-)-Riboflavin on Polymer Functionalized Silica Particles: Application in the Photocatalytic E→Z Isomerization of Polarized Alkenes.

The covalent immobilization of the biomimetic, photo-organocatalyst (-)-riboflavin on silica micro- and nanoparticles via atom transfer radical polymerization (ATRP) is disclosed. Given the effectiveness of (-)-riboflavin as a versatile, environmentally benign photocatalyst, an immobilization strategy based on acrylate-linker modification of the catalyst core and controlled polymerization on initiator pre-functionalized silica particles has been developed. Validation of this approach is demonstrated in the E→Z isomerization of a benchmark cinnamonitrile (Z/E up to 88:12) with 0.

Surface Functionalization with Carboxylic Acids by Photochemical Microcontact Printing and Tetrazole Chemistry.

In this paper, we show that carboxylic acid-functionalized molecules can be patterned by photochemical microcontact printing on tetrazole-terminated self-assembled monolayers. Upon irradiation, tetrazoles eliminate nitrogen to form highly reactive nitrile imines, which can be ligated with several different nucleophiles, carboxylic acids being the most reactive. As a proof of concept, we immobilized trifluoroacetic acid to monitor the reaction with X-ray photoelectron spectroscopy.

Carbohydrate-Responsive Surface Adhesion Based on the Dynamic Covalent Chemistry of Phenylboronic Acid- and Catechol-Containing Polymer Brushes.

A glue, based on dynamic covalent chemistry, with a strong adhesion (2.38 kg cm ), water resistance and carbohydrate responsive reversibility is presented. Using surface initiated atom transfer radical polymerization (SI-ATRP), glass and silicon surfaces were coated with copolymers functionalized with phenylboronic acids and catechols.

On surface O-glycosylation by catalytic microcontact printing.

The generation of carbohydrate patterns on surfaces enables a wide range of analytical and diagnostic applications and efficient methods for carbohydrate immobilization are crucial for this purpose. We report on surface O-glycosylation by catalytic printing as a novel, effective method for the covalent immobilization of carbohydrates in micropatterns. Beside the verification of surface functionalization, the suitability of the generated surface for ligand protein interactions was demonstrated.

Patterning of Nanoclays on Positively Charged Self-Assembled Monolayers via Micromolding in Capillaries.

Nanoclays are nanomaterials with versatile adsorptive properties. This contribution describes the generation of micropatterns of a nanoclay ("laponite") on ammonium-terminated, self-assembled monolayers (SAMs) on glass and silicon. Microstructured immobilization of the laponite was performed using micromolding in capillaries (MIMIC).

Stabilization of High Oxidation State Upconversion Nanoparticles by N-Heterocyclic Carbenes.

The stabilization of high oxidation state nanoparticles by N-heterocyclic carbenes is reported. Such nanoparticles represent an important subset in the field of nanoparticles, with different and more challenging requirements for suitable ligands compared to elemental metal nanoparticles. N-Heterocyclic carbene coated NaYF :Yb,Tm upconversion nanoparticles were synthesized by a ligand-exchange reaction from a well-defined precursor.

Preparation of Functional Alternating Polymer Brushes and Their Orthogonal Surface Modification through Microcontact Printing.

This paper reports microcontact printing (μCP) to immobilize an alkoxyamine initiator (regulator) on glass and silicon substrates and subsequent surface-initiated alternating nitroxide-mediated copolymerization (siNMP) of hexafluoroisopropyl acrylate (HFIPA) and 7-octenylvinyl ether (OVE). The resulting patterned polymer brushes are analyzed by using atomic force microscopy (AFM). In addition, site-specific post-functionalization of the alternating polymer brushes by applying two orthogonal surface reactions is achieved with thiols and amines through μCP.

Supramolecular surface adhesion mediated by azobenzene polymer brushes.

Surface immobilised polymer brushes containing azobenzene units were prepared using a combination of microcontact chemistry and surface-initiated atom transfer radical polymerisation (SI-ATRP). These brushes were investigated using AFM, XPS and UV/vis spectroscopy. It was shown that two surfaces bearing azobenzene brushes can be glued together in the presence of a β-cyclodextrin polymer and hold as much as 700 ± 150 g cm(-2).

Surface patterning with natural and synthetic polymers via an inverse electron demand Diels-Alder reaction employing microcontact chemistry.

Bioorthogonal ligation methods are the focus of current research due to their versatile applications in biotechnology and materials science for post-functionalization and immobilization of biomolecules. Recently, inverse electron demand Diels-Alder (iEDDA) reactions employing 1,2,4,5-tetrazines as electron deficient dienes emerged as powerful tools in this field. We adapted iEDDA in microcontact chemistry (μCC) in order to create enhanced surface functions.