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.

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.

Human Neutrophil Elastase Induces MUC5AC Overexpression in Chronic Rhinosinusitis Through miR-146a

2019 ◽  
Vol 34 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Danqing Yan ◽  
Yu Ye ◽  
Jian Zhang ◽  
Junmei Zhao ◽  
Jieqing Yu ◽  
...  
Keyword(s):  
Chronic Rhinosinusitis ◽  
Neutrophil Elastase ◽  
Human Neutrophil ◽  
Target Gene ◽  
Primary Cultures ◽  
Specific Inhibitor ◽  
Luciferase Reporter ◽  
Human Neutrophil Elastase ◽  
Luciferase Reporter Gene ◽  
Human Nasal Epithelial Cells

Background The pathogenesis of chronic rhinosinusitis (CRS) is not yet clear. microRNAs are widely involved in a number of physiological and pathological processes, of which microRNA-146a (miR-146a) plays an important role in innate immunity, inflammatory response, and other pathophysiological processes. Mucins (MUCs) are important components of secreted mucus, of which MUC5AC is the major MUC secreted in the normal airway. Objective This study was performed to examine human neutrophil elastase (HNE)-induced MUC5AC overexpression in CRS via miR-146a. Methods miR-146a, HNE, epidermal growth factor receptor (EGFR), and MUC5AC expression in the sinonasal mucosa were determined using quantitative real-time polymerase chain reaction (qRT-PCR). EGFR, phosphorylated EGFR (pEGFR), and MUC5AC expression were determined in primary cultures of human nasal epithelial cells (HNECs). We examined the expression of miR-146a, MUC5AC, EGFR, and pEGFR by transfecting HNECs with miR-146a mimics and negative control (NC). Moreover, dual-luciferase reporter gene assays were used to validate EGFR as an hsa-miR-146a target gene. Results miR-146a was significantly downregulated, and HNE, EGFR, and MUC5AC were upregulated in CRS patients both with and without nasal polyps. In the in vitro cell experiment, MUC5AC was significantly downregulated after use of an EGFR-specific inhibitor (AG1478). Upon addition of miR-146a inhibitor, miR-146a was downregulated, while MUC5AC was upregulated. MUC5AC was suppressed in normal primary HNECs by miR-146a mimic and pEGFR was downregulated. The results of dual-luciferase reporter assays showed that the luciferase activities were markedly inhibited in the pGL3-EGFR-3′ UTR+miR-146a mimic group compared with the pGL3+ miR-146a mimic group, suggesting that EGFR is a target gene for miR-146a. Conclusion In HNE-induced CRS, miR-146a downregulates the expression of MUC5AC by inhibiting the activation of EGFR, and EGFR is a target gene of miR-146a.

Neutrophil elastase stimulates tracheal submucosal gland secretion that is inhibited by ICI 200,355

1992 ◽  
Vol 262 (1) ◽  
pp. L86-L91 ◽  
Author(s):  
A. Schuster ◽  
I. Ueki ◽  
J. A. Nadel
Keyword(s):  
Morphometric Analysis ◽  
Therapeutic Intervention ◽  
Neutrophil Elastase ◽  
Human Neutrophil ◽  
Specific Inhibitor ◽  
Gland Secretion ◽  
Maximal Response ◽  
Human Neutrophil Elastase ◽  
Human Tissues ◽  
Submucosal Gland

To investigate whether human neutrophil elastase (HNE) stimulates airway submucosal gland secretion, we studied the effect of purified HNE on secretion of 35S-labeled macromolecules from isolated tracheal tissues from ferrets, dogs, and humans. HNE stimulated secretion in a concentration-dependent fashion, the secretory response being most pronounced in ferret tissues with a maximal response of 1,498 +/- 384% above baseline at 10(-5) M. In dog tissues, maximal secretory responses (509 +/- 169%) to HNE were much greater than to bethanechol (80 +/- 26%). Human tissues obtained several hours postmortem still responded to HNE (179 +/- 48% at 10(-5) M) significantly more than to the combination of isoproterenol, phenylephrine, and bethanechol (23 +/- 10%). Morphometric analysis of canine tracheal tissues showed degranulation of submucosal gland cells after HNE. A specific inhibitor of HNE (ICI 200,355) potently inhibited secretory responses in a concentration-dependent fashion. We suggest that HNE in airways of patients may cause hypersecretion and that treatment with ICI 200,355 may provide a strategy for therapeutic intervention.

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.

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.

scholarly journals Effects of human neutrophil elastase (HNE) on neutrophil function in vitro and in inflamed microvessels

Blood ◽  
1993 ◽  
Vol 82 (7) ◽  
pp. 2188-2195 ◽  
Author(s):  
RC Woodman ◽  
PH Reinhardt ◽  
S Kanwar ◽  
FL Johnston ◽  
P Kubes
Keyword(s):  
Neutrophil Elastase ◽  
Human Neutrophil ◽  
Neutrophil Migration ◽  
Specific Inhibitor ◽  
Neutrophil Infiltration ◽  
Cathepsin G ◽  
Neutrophil Adhesion ◽  
Human Neutrophil Elastase

Abstract The primary objective of this study was to test the hypothesis that human neutrophil elastase (HNE) affects neutrophil infiltration (adhesion and emigration) into inflamed vessels. To determine whether HNE contributes to neutrophil adhesion in vivo, intravital microscopy was used to study neutrophil-endothelial cell interactions in single inflamed postcapillary venules. Superfusion of platelet-activating factor (PAF) (100 nmol/L) onto the mesentery caused an increase in neutrophil-neutrophil interactions, neutrophil adhesion to postcapillary venules, and cellular emigration out of the vasculature. Both L658 758 (an elastase-specific inhibitor), and Eglin C (an elastase and cathepsin G inhibitor) significantly attenuated all of these parameters in vivo. To further characterize the mechanism(s) involved, various in vitro parameters were assessed. HNE, but not trypsin, caused a dose-dependent (0.01 to 1.0 microgram/mL) increase in the expression of the beta subunit (CD18) of the CD11/CD18 adhesive glycoprotein complex on neutrophils. An HNE-dependent increase in CD11b expression was also observed; however, HNE did not affect the expression of other neutrophil adhesion molecules (L-selectin), superoxide production, or degranulation. PAF-enhanced CD18 expression on neutrophils and neutrophil migration were both abolished by L658 758 but PAF-induced neutrophil adhesion to endothelial monolayers was not affected by the antiproteinase. The in vitro data suggest that the antiproteinases do not directly prevent neutrophil adhesion in vivo but may be important in other CD18-dependent events such as neutrophil- neutrophil interaction or neutrophil infiltration (chemotaxis). These results translate into an important, rate-limiting role for elastase in the process of leukocyte infiltration and accumulation in inflamed microvessels.

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