Removal of Thiol-SAM on a Gold Surface for Re-Use of an Interdigitated Chain-Shaped Electrode

Abstract

The self-assembled monolayer (SAM) is the most common organic assembly utilized for the formation of the monolayers of alkane-thiolates on gold electrode, resulting in a wide range of applications for the modified SAM on gold in various research areas. This study examined the desorption of a SAM that was developed on the gold surface of an interdigitated chain-shaped electrode (the ICE, a unique electrode design, was fabricated by our group) with the goal of determining the most efficient strategy of SAM removal for the ICE to be re-used. A simple and proficient solution-based cleaning procedure was applied for the removal of a SAM on the gold surface of the ICE by using a sodium borohydride solution within short-term treatment, resulting in efficiency for the recovery of the originally electrochemical characteristic of ICE of 90.3%. The re-use of ICE after the removal process was confirmed by the successful re-deposition of a SAM onto the electrode surface, resulting in the high efficiency percentage of 90.1% for the reusability of ICE with the SAM modification. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used as tools to investigate the changes in the electrode interface at each stage of the SAM removal and the electrode recycling. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy were employed, being powerful spectrum techniques, for the characterization of the bonding structure and chemical state of the bare ICE and the modified ICE at each treatment step. Based on the comprehensive discussion of analytical chemistry from the obtained EIS and CV data in this study, we confirmed and proved the effectiveness of this promising method for the removal of a SAM from the ICE and the re-use of ICE in the field of material deposition, with the aims of saving money, improving experimental handling, and protecting the environment.

Using Nanomaterials for SARS-CoV-2 Sensing via Electrochemical Techniques

“…The designed biosensor could detect virus samples at sub-fM concentrations and select samples using SPE electrodes (e.g., negative controls, H5N1 influenza A virus, and non-imprinted polymers). Nonetheless, the measurement of peak currents in CV does not contribute to the correction of the charging current because it is typically uncertain, such as the rate constant of a coupled homogeneous reaction or the concentration of the electrolyte [ 57 ]. This limitation complicates the interpretation of data.…”

SAM-Support-Based Electrochemical Sensor for Aβ Biomarker Detection of Alzheimer’s Disease

“…Among these, the working electrode is a crucial component, as the main reaction occurs on its surface, and thus it determines the sensitivity, selectivity, and durability of the sensor. Many kinds of working electrodes have been developed to enhance the selectivity and sensitivity of Aβ electrochemical sensors; these include glassy carbon electrode (GCE) [ 53 , 61 ], paper-based carbon electrode [ 62 , 63 ], screen-printed electrode (SPE) [ 64 ], Ni-foam electrode [ 65 ], and interdigitated microelectrode [ 4 , 34 , 57 , 66 , 67 ]. Amongst these, GCE is very popular but not suitable for miniaturized devices, paper-based carbon electrode is inexpensive and disposable, screen-printed and Ni-foam electrodes are easily fabricated, and interdigitated microelectrode is highly sensitive but requires a prohibited machine and trained technician.…”

“…Self-assembled monolayer (SAM) is ordered arrays of organic molecules and has been employed as monolayers on electrode surfaces in liquid or solid phases in many electronic devices, such as electrochemical sensors [ 4 , 34 , 96 ], batteries [ 54 ], solar cells [ 55 ], and organic field effect transistors (OFETs) [ 56 ], through SAM modification [ 57 ]. The working electrodes modified with SAM are depicted in Figure 4 .…”

“…A self-assembled monolayer (SAM) has been applied in chemical sensors, biosensors, batteries, and electronic devices [ 54 , 55 , 56 ]. In electrochemical sensors, SAM is presented as a conjunction layer on the working electrode surface, which is subjected to electrode modification towards improvement in sensor selectivity and sensitivity relying on functionalities for immobilizing and orientating enzymes and antibodies [ 4 , 34 , 57 , 58 , 59 ]. So, an SAM-appropriate design and fabrication can enhance electrochemical sensor performance.…”

In situ reversible tuning of chemical interface damping in mesoporous silica-coated gold nanorods via direct adsorption and removal of thiol

“…Afterward, the thiolated AuNRs@mSiO 2 particles were immersed in NaBH 4 solution for thiol removal from the AuNR surface, yielding bare AuNRs@mSiO 2 (step 2). 40–42 Organothiols can be removed from Au nanoparticle surfaces using NaBH 4 in water because the hydride derived from NaBH 4 has a higher binding affinity to Au nanoparticles than thiols. 40,42 Therefore, through repeated adsorption and desorption of surface thiols, we attempted to tune the interfacial electron transfer (or CID) in single AuNRs@mSiO 2 .…”