The detailed characterization of electrochemically switchable molecular assemblies on silicon electrodes

Abstract

. (2013). The detailed characterization of electrochemically switchable molecular assemblies on silicon electrodes. Physical Chemistry Chemical Physics, 15 (24), 9879-9890.The detailed characterization of electrochemically switchable molecular assemblies on silicon electrodes AbstractIn this paper we explore a multi-step synthetic strategy toward fabrication of monolayer-modified Si(100) electrodes that can be electrochemically switched. The synthetic scheme is modular and benefits from an established intramolecular lactonization scheme of benzoquinone analogs. A redox-tagged pendant group can be released from the surface such as to allow for in situ monitoring of the switch process. We show that this model system can be used to elucidate chemical and structural events for a surface dynamic system that is rapidly gaining popularity. The influence of polarization times, overpotentials and semiconductor doping type on the kinetic of the switch event is also investigated. In both basic and acidic aqueous electrolytes the release of suitable redox-active markers is found to require unexpectedly large cathodic overpotentials. The release event is accompanied by minor oxidation of the electrode surface and the switched constructs can be regenerated by chemical means with no appreciable deterioration of surface quality. 2013 the Owner Societies. The detailed characterization of electrochemically switchable molecular assemblies on silicon electrodes † Simone Ciampi, a Michael James,z b Moinul H. Choudhury, a Nadim A. Darwish a and J. Justin Gooding* aIn this paper we explore a multi-step synthetic strategy toward fabrication of monolayer-modified Si(100) electrodes that can be electrochemically switched. The synthetic scheme is modular and benefits from an established intramolecular lactonization scheme of benzoquinone analogs. A redox-tagged pendant group can be released from the surface such as to allow for in situ monitoring of the switch process. We show that this model system can be used to elucidate chemical and structural events for a surface dynamic system that is rapidly gaining popularity. The influence of polarization times, overpotentials and semiconductor doping type on the kinetic of the switch event is also investigated.In both basic and acidic aqueous electrolytes the release of suitable redox-active markers is found to require unexpectedly large cathodic overpotentials. The release event is accompanied by minor oxidation of the electrode surface and the switched constructs can be regenerated by chemical means with no appreciable deterioration of surface quality.

Trimethyl Lock: A Multifunctional Molecular Tool for Drug Delivery, Cellular Imaging, and Stimuli‐Responsive Materials

“…[226] Subsequentr elease of hydroquinone 69 leaves an anoscale pattern on the modifieds ilica surfacep resenting amino functions. [231,232] The approach is based on the use of at rimethyl lock moiety to develop model surfaces that can be systematically fine-tuned in systems with defined interactions between the cell and the materiala tt he molecular level. [227][228][229][230] In 2012, Gooding and co-workersr eported am odulars trategy to develop very precise surface chemistry that inhibits cell adhesion with the possibility for electrochemical modulation to facilitate mammalian cell adhesion and to create electrochemically switchable surfaces.…”

“…[231,232] This fascinating surface chemistry might find applications in the field of cell-based sensors, electrochemical devices,a nd artificial substrates for cell biology. The authors demonstrate that upon electrochemical reduction of the quinone TML moiety,t he hydrophilic tag is releaseda nd material B is regenerated, which allows adhesion of BAECs.…”

“…[227][228][229][230] In 2012, Gooding and co-workersr eported am odulars trategy to develop very precise surface chemistry that inhibits cell adhesion with the possibility for electrochemical modulation to facilitate mammalian cell adhesion and to create electrochemically switchable surfaces. [231,232] The approach is based on the use of at rimethyl lock moiety to develop model surfaces that can be systematically fine-tuned in systems with defined interactions between the cell and the materiala tt he molecular level. The chemical assembly protocols of these materials are performed on unoxidized silicon waver surfaces.…”

Nucleic-acid recognition interfaces: how the greater ability of RNA duplexes to bend towards the surface influences electrochemical sensor performance

“…The EIS results can be presented as Bode-plots (Fig. 30,31 At an AC frequency that approaches the time constant of the redox reaction, the value of the phase angle decreases and reaches a minimum. 30,31 At an AC frequency that approaches the time constant of the redox reaction, the value of the phase angle decreases and reaches a minimum.…”

“…1) which allow for a rapid visualization of the kinetics data. 27,30,31 As can be seen in Fig. The frequency at which the phase angle minimum occurs can be used to qualitatively differentiate between systems with different electron-transfer kinetics.…”