Nanotechnology

Protein Immobilization on Ni(II) Ion Patterns Prepared by Microcontact Printing and Dip-Pen Nanolithography

Abstract

An indirect method of protein patterning by using Ni(II) ion templates for immobilization via a specific metal−protein interaction is described. A nitrilotriacetic acid (NTA)-terminated self-assembled monolayer (SAM) allows oriented binding of histidine-tagged proteins via complexation with late first-row transition metal ions, such as Ni(II). Patterns of nickel(II) ions were prepared on NTA SAM-functionalized glass slides by microcontact printing (μCP) and dip-pen nanolithography (DPN) to obtain micrometer and submicrometer scale patterns. Consecutive dipping of the slides in 6His-protein solutions resulted in the formation of protein patterns, as was subsequently proven by AFM and confocal fluorescence microscopy. This indirect method prevents denaturation of fragile biomolecules caused by direct printing or writing of proteins. Moreover, it yields well-defined patterned monolayers of proteins and, in principle, is indifferent for biomolecules with a high molecular weight. This approach also enabled us to characterize the transfer of Ni(II) ions on fundamental parameters of DPN, such as writing speeds and tip−surface contact times, while writing with the smallest possible ink “molecules” (i.e., metal ions).

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Protein Immobilization on Ni(II) Ion Patterns Prepared by Microcontact Printing and Dip-Pen Nanolithography

Micropatterning of emitting layers by microcontact printing and application to organic light-emitting diodes

Abstract

The microcontact printing (μCP) technique, which is a simple and low damage fabrication technique for thin films, was successfully applied to fabricate patterned emitting layers such as polyfluorene (PF). We fabricated micropatterns by transferring dried and uniform thin films, and observed strong electroluminescence (EL) from the fabricated organic light-emitting diodes (OLEDs) with the patterned emitting layers. The performance of the fabricated device was superior to that of a conventionally fabricated device. This demonstrates the well-controlled interfaces achieved by μCP. Furthermore, we succeeded in fabricating OLEDs with multiple emitting layers. These results show that this technique is promising for application to cost-effective, high luminance and multicolored OLED displays.

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Micropatterning of emitting layers by microcontact printing and application to organic light-emitting diodes

Nanoscale Patterns of Dendrimers Obtained by Soft Lithography Using Elastomeric Stamps Spontaneously Structured by Plasma Treatment

Abstract

It is well established that polydimethylsiloxane (PDMS) stamps submitted to an adequate plasma treatment spontaneously develop an ordered surface roughness. In this work, we show that thin layers made of polyamidoamine (PAMAM) dendrimers can be patterned at the nanoscale using these buckled PDMS stamps. The structures accurately reproduce the self-assembled waves observed on the stamp surface after plasma treatment. We discuss the involved transfer of molecules from the stamp to the surface, which relies on molding rather than on printing. Self-assembled networks of lines made of dendrimers with submicrometric pitch can therefore be produced using this process at very low cost without any advanced lithography method for generating hard molds.

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Nanoscale Patterns of Dendrimers Obtained by Soft Lithography Using Elastomeric Stamps Spontaneously Structured by Plasma Treatment

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