Organic Electronics

Molecular Self-Assembly - High Technology Webcast and Tutorial Webinar

   Introduction
   From Molecules to Monolayers: Self-Assembly and Analysis, Molecule by Molecule Webinar
   Basics of Molecular Self-Assembly
   Innovative Materials for Molecular Self-Assembly

Introduction

Molecular self-assembly (MSA) is the assembly of molecules without guidance or management from an outside source. Self-assembly can occur spontaneously in nature, for example, in cells with the self-assembly of the lipid bilayer membrane. It is usually accompanied by an increase in internal organization of the system. Many biological systems use self-assembly to assemble various molecules and structures. Imitating these strategies and creating novel molecules with the ability to self-assemble into supramolecular assemblies is an important technique in nanotechnology.

In self-assembly, the desired end structure is ‘encoded’ in the shape and properties of the molecules that are used, as compared to traditional techniques, such as lithography, where the desired final structure must be carved out from a larger block of matter. Self-assembly is thus referred to as a ‘bottom-up’ manufacturing technique, as compared to lithography being a ‘top-down’ technique. On a molecular scale, the accurate and controlled application of intermolecular forces can lead to new and previously unachievable nanostructures. This is why molecular self-assembly (MSA) is a highly topical and promising field of research in nanotechnology today.

From Molecules to Monolayers: Self-Assembly and Analysis, Molecule by Molecule Webinar

To provide examples of where self-assembly is utilized for high technology applications, Aldrich Materials Science, in collaboration with Materials Today, bring you the recording of a live Webcast that was held on Tuesday, November 17, 2009. The distinguished speakers include:

Professor Paul Weiss

Director of California NanoSystems Institute
Professor - Chemistry and Biochemistry - University of California, Los Angeles

"Self and Directed Assembly of Single Molecule Environments"

Professor Milan Mrksich

Investigator – Howard Hughes Medical Institute - Chicago, IL
Professor - Chemistry - University of Chicago, IL

"Using Self-Assembled Monolayers and Mass Spectrometry for BioChip Applications"

BROADCAST LIVE FROM CNSI / UCLA
We place single molecules and larger groups into precisely controlled environments on surfaces. The monolayer matrices and the inserted molecules can be designed so as to interact directly, to give stability or other properties to supramolecular assemblies. New families of molecules are being developed to yield even greater control and are enabling determination of the key design parameters of both the molecules and assemblies. This in turn is enabling controlled chemical patterning from the sub-nanometer to the centimeter scales. At the same time, a suite of tools is being developed to give unprecedented information on the structures and properties of these assemblies.

BROADCAST LIVE FROM NORTHWESTERN UNIVERSITY
Biochips are prepared by applying an array of proteins, peptides, carbohydrates or other molecules to a flat substrate. They are used to profile enzyme specificities, profile cellular lysates for enzymatic activities, perform high-throughput screening, and other applications. Yet, challenges in immobilizing biomolecules in a functional state and in developing label-based formats to assay biochemical chemical activities still limit the use of these tools. This talk will describe an approach for using mass spectrometry to analyze biochips—including enzyme-mediated reactions of immobilized biomolecules and protein-protein interactions. The method is based on self-assembled monolayers of alkanethiolates on gold that present proteins and small molecules with control over the densities, patterns and orientations of these species. The chips are compatible with matrix-assisted laser desorption ionization mass spectrometry and therefore do not require fluorescent or radioisotopic labels for analysis. This technique, termed SAMDI MS, can efficiently monitor a broad class of enzyme activities—including kinase, protease, methyltransferase and carbohydrate-directed modifications—and can detect proteins having molecular weights up to 100 kD. The talk will describe examples that use peptide arrays to characterize enzyme function.

 

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Basics of Molecular Self-Assembly

The development of self and directed assembly techniques is key for the fabrication of molecularly precise structures for applications ranging from biocompatible and/or bioactive systems to microelectronics.

These applications now demand patterned surface structures with ever-smaller features down to the sub-100 nm scale; however, traditional lithographic techniques such as photolithography cannot reproducibly fabricate such structures with molecular-scale organization. By employing a library of molecules with a spectrum of intermolecular-interaction strengths in conjunction with a variety of thin-film-processing techniques, it is becoming possible to fabricate nanometer-sized surface features with molecular precision.

The basics of the self-assembly process are illustrated in the tutorial webinar brought to you by Sigma-Aldrich in association with Asemblon™.





For Self-Assembled Monolayers (SAMs), synthetic chemistry is used only to construct the basic building blocks (that is, the constituent molecules), and weaker intermolecular bonds such as Van der Waals bonds are involved in arranging and binding the blocks together into a structure. This weak bonding makes solution, and hence reversible, processing of SAMs (and in general, MSA) possible. Thus, solution processing and manufacturing of SAMs offer the enviable goal of mass production with the possibility of error correction at any stage of assembly. It is well recognized that this method could prove to be the most cost-effective way for the semiconductor electronics industry to produce functional nanodevices such as nanowires, nanotransistors, and nanosensors in large numbers.

For more information on Molecular Self-Assembly and the associated materials that Aldrich Materials Science offers to enable this technology, please visit our Material Matters™ page to view issues on Molecular Self-Assembly (Vol 1. No. 2), Nanoscale Surface Modifications (Vol 3. No.2) and much more.

Your questions, comments and suggestions are always welcome by contacting us at: matsci@sial.com.