Chemistry

Modification of Surfaces by Chemical Transfer Printing Using Chemically Patterned Stamps

Abstract

The preparation of well-defined molecular monolayers and their patterning on the microscale and nanoscale are key aspects of surface science and chemical nanotechnology. In this article, we describe the modification of amine-functionalized surfaces using a new type of 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 the presence of coupling agents such as diisopropylcarbodiimide (DIC). The generated active esters can be reacted by placing the stamps in contact with amine-functionalized surfaces. The process leads to the transfer of acyl residues from the stamp to the substrate and therefore to a covalent attachment. Patterning occurs because of the fact that reaction and transfer take place only in areas with TFP groups present on the stamp surface. Different types of amine-decorated surfaces were successfully modified, and the transfer was visualized by fluorescence microscopy. To the best of our knowledge, the covalent transfer printing (CTP) of an immobilized molecular monolayer from one surface to another surface is unprecedented.

Link

Modification of Surfaces by Chemical Transfer Printing Using Chemically Patterned Stamps

Covalent microcontact printing of biomolecules

Abstract

Soft lithography offers great potential for the fabrication of 2D and 3D patterned structures using a variety of materials and patterns. It complements and extends conventional fabrication methods. This thesis is particularly focus on microcontact printing (μCP) as a method to create biological patterns on surfaces and also as a tool used in “in-situ” synthesis. Microcontact printing has unique features that make this technique very attractive: (i) it is simple to introduce in any laboratory, (ii) it is biocompatible, (iii) it can fabricate features below 100 nm, (iv) it is applicable to broad range of materials, (v) it is efficient and not expensive. The important feature is that stamp which is used for printing is flexible and can seal conformally to the surface tolerating the nanoscale roughness. In this thesis the focus is on the application of soft lithography in the fabrication of microsystems useful in studying interactions between biomolecules and cells.

Link

Covalent microcontact printing of biomolecules

Microcontact Printing for Creation of Patterned Lipid Bilayers on Tetraethylene Glycol Self-Assembled Monolayers

Abstract

Supported lipid bilayers (SLBs) formed on many different substrates have been widely used in the study of lipid bilayers. However, most SLBs suffer from inhomogeneities due to interactions between the lipid bilayer and the substrate. In order to avoid this problem, we have used microcontact printing to create patterned SLBs on top of ethylene-glycol-terminated self-assembled monolayers (SAMs). Glycol-terminated SAMs have previously been shown to resist absorbance of biomolecules including lipid vesicles. In our system, patterned lipid bilayer regions are separated by lipid monolayers, which form over the patterned hexadecanethiol portions of the surface. Furthermore, we demonstrate that α-hemolysin, a large transmembrane protein, inserts preferentially into the lipid bilayer regions of the substrate.

Link

Microcontact Printing for Creation of Patterned Lipid Bilayers on Tetraethylene Glycol Self-Assembled Monolayers

Page 1 of 15