The Role of Liquid Ink Transport in the Direct Placement of Quantum Dot Emitters onto Sub-Micrometer Antennas by Dip-Pen Nanolithography.

Dip-pen nanolithography (DPN) is used to precisely position core/thick-shell ("giant") quantum dots (gQDs; ≥10 nm in diameter) exclusively on top of silicon nanodisk antennas (≈500 nm diameter pillars with a height of ≈200 nm), resulting in periodic arrays of hybrid nanostructures and demonstrating a facile integration strategy toward next-generation quantum light sources. A three-step reading-inking-writing approach is employed, where atomic force microscopy (AFM) images of the pre-patterned substrate topography are used as maps to direct accurate placement of nanocrystals. The DPN "ink" comprises gQDs suspended in a non-aqueous carrier solvent, o-dichlorobenzene.

Miniaturization of multiplexed planar recombinant antibody arrays for serum protein profiling.

Background: Antibody-based microarrays are a developing tool for high-throughput proteomics in health and disease. However, in order to enable global proteome profiling, novel miniaturized high-density antibody array formats must be developed.

Results: In this proof-of-concept study, we have designed a miniaturized planar recombinant (single-chain Fragment variable).

Nanografting for surface physical chemistry.

This article reveals the enabling aspects of nanografting (an atomic force microscopy-based lithography technique) in surface physical chemistry. First, we characterize self-assembled monolayers and multilayers using nanografting to place unknown molecules into a matrix with known structure or vice versa. The availability of an internal standard in situ allows the unknown structures to be imaged and quantified.

Molecular-level approach to inhibit degradations of alkanethiol self-assembled monolayers in aqueous media.

A molecular-level approach is developed to prevent or inhibit the degradation processes of alkanethiol self-assembled monolayers (SAMs). Previous studies revealed two degradation pathways: direct desorption and oxidation-desorption. By use of scanning tunneling microscopy (STM) and atomic force microscopy (AFM), in situ and time-dependent imaging reveals and confirms that degradations of alkanethiol SAMs on gold mainly initiate at defect sites, such as domain boundaries and vacancy islands, and then propagate into the ordered domains.

Positioning protein molecules on surfaces: a nanoengineering approach to supramolecular chemistry.

We discuss a nanoengineering approach for supramolecular chemistry and self assembly. The collective properties and biofunctionalities of molecular ensembles depend not only on individual molecular building blocks but also on organization at the molecular or nanoscopic level. Complementary to "bottom-up" approaches, which construct supramolecular ensembles by the design and synthesis of functionalized small molecular units or large molecular motifs, nanofabrication explores whether individual units, such as small molecular ligands, or large molecules, such as proteins, can be positioned with nanometer precision.