Self-assembly of thiols

It has been found ]145] that the self-assembly of thiol molecules on Au(lll) from ethanolic solution depends significantly on the electrode potential. Especially at cathodic potentials, chemisorption of thiol molecules and the development of a highly ordered structure are slowed down significantly. 

Moore, A. J., Goldenberg, L. M., Bryce, M. R., etal, New crown annelated tetrathiafulvalenes Synthesis, electrochemistry, self-assembly of thiol derivatives, and metal cation recognition. J. Org. Chem. 2000, 65, 8269-8276. 

The fact that self-assembly of thiols on gold makes it possible to create well-defined surfaces with controlled properties was used extensively to understand the forces controlling orientation of liquid crystals adsorbed at surfaces545 - 549. 

Figure 7.2. (a] DNA film formed by self-assembly of thiol containing ODN onto Au surfaces, (b] DNA film formed by self-assembly followed by a dilution step with an alkylthiol diluents. 

Conversely, DNA is functionally and structurally more stable than proteins it is easier to handle and interacts more favorably with surfaces. This provides a larger window for the choice of substrate, as well as for variations in attachment strategies. Many different schemes have been developed for immobilization of DNA and oligonucleotides on solid surfaces. Some thoroughly studied routes include covalent or electrostatic linking via functional silanized monolayers (see below), self-assembly of thiol-derivatized oligonucleotides on gold surfaces (Steel, 1999), or assembly of LB monolayers at the air-water interface (Okahata, 1996 Ijiro, 1996). 

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