Direct Route to Well-Defined, Chemically Diverse Electrode Arrays

Abstract

The selective placement of molecules of interest at specific locations on surfaces is a keystone for the bridge between interfacial science and technology. One approach to this problem is the use of electrochemistry to direct interfacial reactions that immobilize species from solution onto surfaces. In this study, sets of individually functionalized gold electrodes were formed by the selective formation of monolayers from four different alkyl thiosulfates. Analysis of the arrays using spatially resolved X-ray photoelectron spectroscopy (XPS) revealed each type of functionality exclusively on the electrode to which it was directed. The wetting behavior of these surfaces was also consistent with homogeneous monolayers placed selectively on each electrode. The flexibility of this method provides the ability to produce a wide variety of chemical patterns at interfaces of interest for a range of technological applications.

Switching On/Off the Chemisorption of Thioctic-Based Self-Assembled Monolayers on Gold by Applying a Moderate Cathodic/Anodic Potential

“…It is interesting to note that after each SAM desorption at +0.5 V, the signal of ferrocene completely vanished, indicating that the gold electrode could be completely cleaned from the SAM, in situ, and then reused for a new deposition. This is a very appealing property that may be useful for electrically addressing the patterning of SAMs [51][52][53][54] and for electrochemically modifying individually addressable electrodes in an interdigitated array, 15,9,[55][56][57][58] under "soft" conditions. Concerning the exact mechanisms of the chemisorption/desorption reactions and the influence of the electrical potential on these reactions, only speculative explanations can be proposed at the moment.…”

Chip-Scale Electrochemical Differentiation of SAM-Coated Gold Features Using a Probe Array

“…However, if distances between the features to be differentiated is sufficiently large (several millimeters or more), it is enough if only the active potential is controlled. 11 Here, we have a large number of features distributed over the whole area of the die (6.5 × 3.8 mm 2 ) and it is important to see what the resistances through the electrolyte are in this case.…”

“…1,2 The other involved toposelective electrochemistry 3,4 which is applicable to any micron-scale structure that can be electrically isolated; this approach would be clearly preferable over the "guide" method if it were scalable. The selective electrochemistry approach is based on reductive desorption of a SAM [4][5][6][7][8][9][10][11] and was demonstrated on electrically isolated arms of a single plasmonic gold interferometer. 3 Alternative techniques for "microspotting", such as contact microprinting 12 and dip-pen lithography, 13 may also be viable for this purpose but require specialized, dedicated equipment and/or processes.…”

DNA self-assembly-driven positioning of molecular components on nanopatterned surfaces

“…This can be repeated sequentially to pattern different DNA anchors across the surface. This technique has been demonstrated for monolayer patterning [17], DNA [15,18] and peptide binding [19] as well as cell capture and release [20], and potentially allows the wiring of individual molecular constructs in a site-directed fashion.…”