Gold-thiolate interaction

Covalent attachment of enzymes to surfaces is often intuitively perceived as being more reliable than direct adsorption, but multisite physical interactions can in fact yield a comparably strong and stable union, as demonstrated by several biological examples. The biotin/streptavidin interaction requires a force of about 0.3 nN to be severed [Lee et al., 2007], and protein/protein interactions typically require 0.1 nN to break, but values over 1 nN have also been reported [Weisel et al., 2003]. These forces are comparable to those required to mpture weaker chemical bonds such as the gold-thiolate bond (1 nN for an alkanethiol, and even only 0.3 nN for a 1,3-aUcanedithiol [Langry et al., 2005]) and the poly(His)-Ni(NTA) bond (0.24 nN, [Levy and Maaloum, 2005]). 

Figure 4.11 Schematic of S-layer stabilized solid supported lipid membranes, (a) S-layer directly recrystallized on gold, with a lipid bilayer on top. (b) Same as (a), with an additional S-layer recrystallized on top of the lipid bilayer, (c) Thiolated SCWPs directly bound to gold and interacting with an S-layer, with a lipid bilayer on top. (d) Same as (c).

Kruger, D., Fuchs, H., Rousseau, R., Marx, D. and Parinello, M. (2001) Interaction of short-chain alkane thiols and thiolates with small gold clusters Adsorption structures and energetics. Journal of Chemical Physics, 115, 4776-4786. 

Figure 22 Some thiolate gold(I) complexes with several secondary interactions.

---