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Time-of-flight secondary ion mass spectrometry (ToF-SIMS) can be used to image biological samples with nanometer-scale resolution, albeit with the drawback that it often cannot detect large molecular signals. One way to increase secondary ion molecular yield is to chemicallymodify the surface in the so-calledmatrix-enhanced SIMS(ME-SIMS) approach, which is based on embedding analyte molecules in low-weight organic matrices. In this study, a solvent-free sample preparation technique was employed using sublimation/deposition for coating a mouse brain section with a thin layer of a 2,5-dihydroxybenzoic acid (DHB) matrix. Using this preparation technique, signal enhancements of up to a factor of 18 could be detected. Itwas found that thematrix layer thickness plays an important role in the efficiency of yield enhancement. Also, a complex influence of the matrix layer on various signals was observed. [ABSTRACT FROM AUTHOR]

Vesicles are dynamic supramolecularstructures with a bilayer membraneconsisting of lipids or syntheticamphiphiles enclosing an aqueous compartment. Lipid vesicles haveoften been considered as mimics for biological cells. In this paper,we present a novel strategy for the preparation of three-dimensionalmultilayered structures in which vesicles containing amphiphilic β-cyclodextrinare interconnected by proteins using cyclodextrin guests as bifunctionallinker molecules. We compared two pairs of adhesion molecules forthe immobilization of vesicles: mannose–concanavalin A andbiotin–streptavidin. Microcontact printing and thiol–eneclick chemistry were used to prepare suitable substrates for the vesicles.Successful immobilization of intact vesicles through the mannose–concanavalinA and biotin–streptavidin motifs was verified by fluorescencemicroscopy imaging and dynamic light scattering, while the vesicleadlayer was characterized by quartz crystal microbalance with dissipationmonitoring. In the case of the biotin–streptavidin motif, upto six layers of intact vesicles could be immobilized in a layer-by-layerfashion using supramolecular interactions. The construction of vesiclemultilayers guided by noncovalent vesicle–vesicle junctionscan be taken as a minimal model for artificial biological tissue. [ABSTRACT FROM AUTHOR]

The preparation of well-defined molecular monolayersand theirpatterning on the microscale and nanoscale are key aspects of surfacescience and chemical nanotechnology. In this article, we describethe modification of amine-functionalized surfaces using a new typeof contact printing based on chemically patterned, flat PDMS stamps.The stamps have discrete areas with surface-bond tetrafluorophenol(TFP) groups, which allow the attachment of carboxylic acids in thepresence of coupling agents such as diisopropylcarbodiimide (DIC).The generated active esters can be reacted by placing the stamps incontact with amine-functionalized surfaces. The process leads to thetransfer of acyl residues from the stamp to the substrate and thereforeto a covalent attachment. Patterning occurs because of the fact thatreaction and transfer take place only in areas with TFP groups presenton the stamp surface. Different types of amine-decorated surfaceswere successfully modified, and the transfer was visualized by fluorescencemicroscopy. To the best of our knowledge, the covalent transfer printing(CTP) of an immobilized molecular monolayer from one surface to anothersurface is unprecedented. [ABSTRACT FROM AUTHOR]

Triazolinedione (TAD) click reactions were combined with microcontact chemistry to print, erase, and reprint polymer brushes on surfaces. By patterning substrates with a TAD-tagged atom-transfer radical polymerization initiator (ATRP-TAD) and subsequent surface initiated ATRP, it was possible to graft micropatterned polymer brushes from both alkene- and indole-functionalized substrates. As a result of the dynamic nature of the Alder-ene adduct of TAD and indole at elevated temperatures, the polymer pattern could be erased while the regenerated indole substrate could be reused to print new patterns. To demonstrate the robustness of the methodology, the write-erase cycle was repeated four times., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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. μCC is a straightforward soft-lithography technique which enables fast and large area patterning with high pattern resolutions. In this work, tetrazine functionalized surfaces were reacted with carbohydrates conjugated with norbornene or cyclooctyne acting as strained electron rich dienophiles employing μCC. It was possible to create monofunctional as well as bifunctional substrates which were specifically addressable by proteins. Furthermore we structured glass supported alkene terminated self-assembled monolayers with a tetrazine conjugated atom transfer radical polymerization (ATRP) initiator enabling surface grafted polymerizations of poly(methylacrylate) brushes. The success of the surface initiated iEDDA via μCC as well as the functionalization with natural and synthetic polymers was verified via fluorescence and optical microscopy, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), atomic force microscopy (AFM) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR).

Patchy surfaces: An azide-terminated self-assembled monolayer was patterned with the peptide sequence (EIAALEK)(3) by using microcontact printing. This sequence forms stable coiled-coil heterodimers with the complementary peptide (KIAALKE)(3). By introducing this peptide to the surface of phospholipid liposomes and cyclodextrin vesicles, liposomes and vesicles can be immobilized at the patterned surface., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)