Self alkanethiol-based

Olsen C, Rowntree PA. (1998) Bond-selective dissociation of alkanethiol based self-assembled monolayers adsorbed on gold substrates, using low-energy electron beams. / Chem Phys 108 3750-3764. 

Despite their popularity for the functionalization of Au surfaces, chemisorbed thiols may have limited stability when exposed to physiological conditions. A number of reports have demonstrated that chemisorbed alkanethiols are readily displaced by surface exchange by other molecules " (including biogenic thiols such as glutathione), and desorb at an appreciable rate under oxidative conditions or in the presence of electrolyte. These pathways compromise the integrity of alkanethiol-based self-assembled monolayers, with less than positive consequences for in vivo applications. 

The I(V) curves displayed in Figure 6.3 are actually for thousands of molecules in the nanopore cofiguration (see Chapter 4). It is important to determine whether these discrete states occur on the individual molecular scale or are simply a group phenomenon. To address this question, several individual molecules were dispersed in an alkanethiol-based SAM (self-assembled monolayer) and tracked via STM over several hours. Figure 6.4 shows a single molecule turn on , off and back on again. Each frame represents three minutes. 

DEVELOPMENT OF A DNA SENSOR BASED ON ALKANETHIOL SELF-ASSEMBLED MONOLAYER-MODIFIED... 

Herbicides, like demestryn, have been determined using a chemosensor based on the MIP film recognition and capacitive transduction [193, 194]. In this determination, photografting polymerization has been demonstrated as an efficient procedure for fabrication of a capacitive chemosensor. This procedure involved immobilization of an initiator on the electrode. In this case, first, an alkanethiol monolayer was self-assembled on the gold electrode. This monolayer was perfectly dielectric. Then, an MIP film was deposited on top of this monolayer by photo-radical polymerization in the acetone solution with benzophenone, 2-acrylamido-2-methyl-1-propane sulphonic acid, /V./V -iriethylenediacrylamide and demestryn used as the initiator, cross-linker, functional monomer and template, respectively. Subsequently, the template was extracted with methanol. The capacitance decreased by 20% upon binding the demestryn analyte by the MIP film. Similarly, a creatine chemosensor was constructed [194],... 

With conventional chips, it is well known that thiolated-DNA can be easily immobilized on gold but does not interact by ordered self-assembly, due to nonspecific interactions between the DNA bases and the gold. Different alkanethiols have been used to improve the hybridization efficiency and the selectivity, followed by immobilization of thiolated-DNA on the substrate [59,61,69]. Hence, this method requires two steps and needs consideration concerning the experimental conditions. However, DNA-conjugated polymer does not only prevent desorption of probe DNA from the surface, because the DNA is covalently bound to the self-assembly polymer, but it also... 

Fig. 4.2 Schematic of alkanethiol monolayer-modified gold-coated AFM tip used for CFM and interactions between exposed functional groups on the contacting surfaces (right chemically modified AFM tip and functionalized surface. Different functionalities, and interactions are indicated by different gray scales and arrows, respectively). For details on the self-assembled monolayer-based tip functionalization, see text (adapted/reproduced with permission from [11])...

Hybridization and one-base mismatch detection was performed by using self-assembled monolayer (SAM) on gold electrodes in the presence of MB indicator first time [61]. 14-mer short oligonucleotides were immobilized onto Au electrode surface by using alkanethiol monolayer coupling at surface. Mercaptopropionic acid (MPA) was used for monolayer production. Voltammetric reduction signal of MB was monitored for hybridization and mismatch detection. 

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