Switching the Electrochemical Impedance of Low-Density Self-Assembled Monolayers†

Langmuir ◽  
2007 ◽  
Vol 23 (1) ◽  
pp. 297-304 ◽  
Author(s):  
David K. Peng ◽  
Sandy T. Yu ◽  
David J. Alberts ◽  
Joerg Lahann
Keyword(s):  
Electrochemical Impedance ◽  
Self Assembled Monolayers ◽  
Low Density ◽  
Assembled Monolayers ◽  
Self Assembled

scholarly journals Microfluidic Impedance Biosensor Chips Using Sensing Layers Based on DNA-Based Self-Assembled Monolayers for Label-Free Detection of Proteins

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 80
Author(s):  
Khaled Alsabbagh ◽  
Tim Hornung ◽  
Achim Voigt ◽  
Sahba Sadir ◽  
Taleieh Rajabi ◽  
...  
Keyword(s):  
Troponin I ◽  
Electrochemical Impedance ◽  
Specific Binding ◽  
Self Assembled Monolayers ◽  
Significant Shift ◽  
Label Free ◽  
Label Free Detection ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Biosensor Chip

A microfluidic chip for electrochemical impedance spectroscopy (EIS) is presented as bio-sensor for label-free detection of proteins by using the example of cardiac troponin I. Troponin I is one of the most specific diagnostic serum biomarkers for myocardial infarction. The microfluidic impedance biosensor chip presented here consists of a microscope glass slide serving as base plate, sputtered electrodes, and a polydimethylsiloxane (PDMS) microchannel. Electrode functionalization protocols were developed considering a possible charge transfer through the sensing layer, in addition to analyte-specific binding by corresponding antibodies and reduction of nonspecific protein adsorption to prevent false-positive signals. Reagents tested for self-assembled monolayers (SAMs) on gold electrodes included thiolated hydrocarbons and thiolated oligonucleotides, where SAMs based on the latter showed a better performance. The corresponding antibody was covalently coupled on the SAM using carbodiimide chemistry. Sampling and measurement took only a few minutes. Application of a human serum albumin (HSA) sample, 1000 ng/mL, led to negligible impedance changes, while application of a troponin I sample, 1 ng/mL, led to a significant shift in the Nyquist plot. The results are promising regarding specific detection of clinically relevant concentrations of biomarkers, such as cardiac markers, with the newly developed microfluidic impedance biosensor chip.

Chemical, Electrochemical, and Structural Stability of Low-Density Self-Assembled Monolayers

Langmuir ◽  
2007 ◽  
Vol 23 (20) ◽  
pp. 10184-10189 ◽  
Author(s):  
David K. Peng ◽  
Joerg Lahann
Keyword(s):  
Structural Stability ◽  
Self Assembled Monolayers ◽  
Low Density ◽  
Assembled Monolayers ◽  
Self Assembled

Electrochemical impedance spectroscopy investigations on the L-cysteine-thiolate self-assembled monolayers formed at p-GaAs(100) electrodes

2014 ◽  
Vol 131 ◽  
pp. 42-51 ◽  
Author(s):  
Valentina Lazarescu ◽  
Mirela Enache ◽  
Mihai Anastasescu ◽  
Gianina Dobrescu ◽  
Catalin Negrila ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled

scholarly journals Corrosion Protection of AA7075 Aluminium Alloy by Trimethoxy-Silanes Self-Assembled Monolayers

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Rodrigo S. Neves ◽  
Daiane P. B. Silva ◽  
Artur J. Motheo
Keyword(s):  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Reduction Reaction ◽  
Self Assembled Monolayers ◽  
Organic Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Surface Modified ◽  
Trimethoxy Silane

This study presents electrochemical data concerning the aluminium alloy AA7075 surface modified by self-assembled monolayers (SAMs) of octadecyl-trimethoxy-silane and propyl-trimethoxy-silane. Polarisation curves have shown SAMs blocking effect, as they partially block the oxygen reduction reaction and displace the corrosion potential to positive values. Electrochemical impedance spectroscopy experiments have suggested that the protective effect comes from the oxide layer stabilization by the organic monolayers, which block the corroding species diffusion to the surface. These results show the potential of using methoxy-silanes SAMs as corrosion protective coatings; however, they are also indicative of the superior octadecyl-trimethoxy-silane protective characteristics.

Electrochemical impedance spectroscopy of carboxylic-acid terminal alkanethiol self assembled monolayers on GaAs substrates

2010 ◽  
Vol 55 (28) ◽  
pp. 8758-8765 ◽  
Author(s):  
Lingling Wu ◽  
Fernanda Camacho-Alanis ◽  
Homero Castaneda ◽  
Giovanni Zangari ◽  
Nathan Swami
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Carboxylic Acid ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Self Assembled Monolayers ◽  
Gaas Substrates ◽  
Assembled Monolayers ◽  
Self Assembled

scholarly journals An impedance investigation of corrosion protection of copper by self-assembled monolayers of alkanethiols in aqueous solution

2004 ◽  
Vol 69 (10) ◽  
pp. 791-805 ◽  
Author(s):  
Guiyan Li ◽  
Houyi Ma ◽  
Yongli Jiao ◽  
Shrnhao Chen
Keyword(s):  
Equivalent Circuit ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Copper Substrate ◽  
Self Assembled Monolayers ◽  
Copper Surfaces ◽  
Hydrophobic Barrier ◽  
Assembled Monolayers ◽  
Covered Electrodes ◽  
Self Assembled

Self-assembled monolayers (SAMs) of three n-alkanethiols, 1-octadecanethiol (C18SH), 1-dodecanethiol (C12SH), and 1-hexanethiol (C6SH), were formed on fresh, oxide- free copper surfaces obtained by HNO3 etching. The corrosion protection abilities of the three alkanethiol SAM s were evaluated in 0.2 mol cm-3 NaCl, 0.2 mol cm-3 HCl and 0.2 mol dm?3 H2SO4 solutions using the electrochemical impedance spectroscopy (EIS) method. The SAMs act as a hydrophobic barrier layer, which effectively prevents the copper substrate from contacting corrosive ions, thereby inhibiting corrosion of the copper to a considerable degree. A general equivalent circuit for the SAM-covered electrodes was proposed, bymeans of which the impedance behavior of the electrodes was interpreted and the corresponding electrochemical parameters were acquired. In addition, the quality of the SAMs and development of defects in the SAMs were also been evaluated based on the equivalent circuit. The dependence of the capacitance of the SAMs on the applied potentials was used to determine the stability of the SAMs at the applied potentials.

Mixed Self-Assembled Monolayers Modified Electrode for the Detection of Human Neutrophil Elastase

2014 ◽  
Vol 898 ◽  
pp. 308-311
Author(s):  
Wei Kun Li ◽  
Yu Jun Yang
Keyword(s):  
Neutrophil Elastase ◽  
Human Neutrophil ◽  
Electrochemical Impedance ◽  
Specific Inhibitor ◽  
Differential Pulse ◽  
Self Assembled Monolayers ◽  
Human Neutrophil Elastase ◽  
Redox Potentials ◽  
Assembled Monolayers ◽  
Self Assembled

A novel electrochemical sensor has been developed based on the specificity of the molecular recognition of human neutrophil elastase (HNE) provided by its specific inhibitor, sivelestat. First, the gold surfaces were modified with homogeneously mixed cysteamine and 6-ferrocenyl-1-hexanethiol (FcHT) to generate a mixed self-assembled monolayers (mSAM) modified Au electrode. Then the sivelestat was covalently attached to the mSAM by its carboxylic group to the amino group with the use of activating reagents: 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxy-sulfosuccinimide (NHS). Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) was used to monitor the sensor assembly and the recognition of HNE on surfaces. Upon the selective binding of HNE to the surface bound sivelestat, the redox potentials of the ferrocene moiety of the mSAM shifted positively together with a decrease of the peak current. A clinically relevant range of HNE concentrations was successfully detected in pH 7.4 phosphate buffer.

Photopatterning of Stable, Low-Density, Self-Assembled Monolayers on Gold

Langmuir ◽  
2015 ◽  
Vol 31 (9) ◽  
pp. 2689-2696 ◽  
Author(s):  
Leila Safazadeh ◽  
Brad J. Berron
Keyword(s):  
Self Assembled Monolayers ◽  
Low Density ◽  
Assembled Monolayers ◽  
Self Assembled
Sign in / Sign up

Export Citation Format

Share Document