Covalent Immobilization of Urease on Poly(Pyrrole-3-carboxylic Acid): Electrochemical Impedance and Mott Schottky Study

2016 ◽  
Vol 163 (8) ◽  
pp. B435-B444 ◽  
Author(s):  
Tolga Karazehir ◽  
Murat Ates ◽  
A. Sezai Sarac
Keyword(s):  
Carboxylic Acid ◽  
Electrochemical Impedance ◽  
Covalent Immobilization

Surface Immobilization of Synthetic Proteins Via Plasma Polymer Interlayers

1998 ◽  
Vol 544 ◽  
Author(s):  
Hans J Griesser ◽  
Keith M McLean ◽  
Gerrit J Beumer ◽  
Xiaoyi Gong ◽  
Peter Kingshot ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Cell Attachment ◽  
Plasma Layer ◽  
Polymeric Materials ◽  
Covalent Immobilization ◽  
Biologically Active ◽  
Plasma Polymer ◽  
Rf Plasma ◽  
Bulk Materials ◽  
Synthetic Proteins

AbstractCoatings of biologically active molecules on synthetic ”bulk“materials are of much interest for biomedical applications since they can in principle elicit specific, predictable. controlled responses of the host environment to an implanted device. However, issues such as shelf life. storage conditions, biological safety, and enzymatic attack in the biological environment must be considered; synthetic proteins may offer advantages. In this study we investigated the covalent immobilization onto polymeric materials of synthetic proteins which possess some properties that mimic those of the natural protein collagen, particularly the ability to form triple helical structures, and thus may provide similar bio-responses while avoiding enzymatic degradation. In order to perform immobilization of these collagen-like molecules (CLMs) under mild reaction conditions, the bulk materials are first equipped with suitable surface groups using rf plasma methods. Plasma polymer interlayers offer advantages as versatile reactive platforms for the immobilization of proteins and other biologically active molecules. Application of a thin plasma polymer coating from an aldehyde monomer is particularly suitable as it enables direct immobilization of CLMs by reaction with their terminal amine groups, using reductive amination chemistry. An alternative route is via plasma polymer layers that contain carboxylic acid groups and using carbodiimnide chemistry. A third route makes use of alkylamme plasma polymer interlayers, which are less process sensitive than aldehyde and acid plasma coatings. A layer of poly-carboxylic acid compounds such as carboxylic acid terminated PAMAM-starburst dendrimers or carboxymethylated dextran is then attached by carbodiimide chemistry onto the amine plasma layer. Amine-terminated CLMs can then be immobilized onto the poly-carboxylic acid layer. Surface analytical methods have been used to characterize the immobilization steps and to assess the surface coverage. Initial cell attachment and growth assays indicate that the biological performance of the CLMs depends on their amino acid sequence.

scholarly journals Molecularly Imprinted Polyscopoletin for the Electrochemical Detection of the Chronic Disease Marker Lysozyme

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Tiziano Di Giulio ◽  
Elisabetta Mazzotta ◽  
Cosimino Malitesta
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Mammalian Species ◽  
Covalent Immobilization ◽  
Amino Groups ◽  
Molecularly Imprinted ◽  
Disease Marker ◽  
Sensing Material ◽  
Enzymatic Marker ◽  
L 62

Herein we report the electropolymerization of a scopoletin based molecularly imprinted polymer (MIP) for the detection of lysozyme (Lyz), an enzymatic marker of several diseases in mammalian species. Two different approaches have been used for the imprinting of lysozyme based, respectively, on the use of a monomer-template mixture and on the covalent immobilization of the enzyme prior to polymer synthesis. In the latter case, a multi-step protocol has been exploited with preliminary functionalization of gold electrode with amino groups, via 4-aminothiophenol, followed by reaction with glutaraldehyde, to provide a suitable linker for lysozyme. Each step of surface electrode modification has been followed by cyclic voltammetry and electrochemical impedance spectroscopy, which has been also employed to test the electrochemical responses of the developed MIP. The sensors show good selectivity to Lyz and detect the enzyme at concentrations up to 292 mg/L (20 μM), but with different performances, depending on the used imprinting approach. An imprinting factor equal to 7.1 and 2.5 and a limit of detection of 0.9 mg/L (62 nM) and 2.1 mg/L (141 nM) have been estimated for MIPs prepared with and without enzyme immobilization, respectively. Competitive rebinding experiment results show that this sensing material is selective for Lyz determination. Tests were performed using synthetic saliva to evaluate the potential application of the sensors in real matrices for clinical purposes.

scholarly journals Electrochemical Detection Platform Based on RGO Functionalized with Diazonium Salt for DNA Hybridization

Biosensors ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 39
Author(s):  
Elena A. Chiticaru ◽  
Luisa Pilan ◽  
Mariana Ioniţă
Keyword(s):  
Charge Transfer ◽  
Dna Hybridization ◽  
Electrochemical Impedance ◽  
Diazonium Salt ◽  
Modified Electrodes ◽  
Covalent Immobilization ◽  
Fabrication Process ◽  
Label Free ◽  
Modified Dna ◽  
Electron Transfer Properties

In this paper, we propose an improved electrochemical platform based on graphene for the detection of DNA hybridization. Commercial screen-printed carbon electrodes (SPCEs) were used for this purpose due to their ease of functionalization and miniaturization opportunities. SPCEs were modified with reduced graphene oxide (RGO), offering a suitable surface for further functionalization. Therefore, aryl-carboxyl groups were integrated onto RGO-modified electrodes by electrochemical reduction of the corresponding diazonium salt to provide enough reaction sites for the covalent immobilization of amino-modified DNA probes. Our final goal was to determine the optimum conditions needed to fabricate a simple, label-free RGO-based electrochemical platform to detect the hybridization between two complementary single-stranded DNA molecules. Each modification step in the fabrication process was monitored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using [Fe(CN)6]3−/4− as a redox reporter. Although, the diazonium electrografted layer displayed the expected blocking effect of the charge transfer, the next steps in the modification procedure resulted in enhanced electron transfer properties of the electrode interface. We suggest that the improvement in the charge transfer after the DNA hybridization process could be exploited as a prospective sensing feature. The morphological and structural characterization of the modified electrodes performed by scanning electron microscopy (SEM) and Raman spectroscopy, respectively, were used to validate different modification steps in the platform fabrication process.

scholarly journals Study of New Thiazole Based Pyridine Derivatives as Potential Corrosion Inhibitors for Mild Steel: Theoretical and Experimental Approach

2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
T. K. Chaitra ◽  
K. N. Mohana ◽  
H. C. Tandon
Keyword(s):  
Carboxylic Acid ◽  
Mild Steel ◽  
Experimental Approach ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Pyridine Derivatives ◽  
Ionisation Potential ◽  
Transfer Resistance ◽  
Inhibition Performance

Three new thiazole based pyridine derivatives 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-2-ylmethylene-hydrazide (2-MTPH), 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-3-ylmethylene-hydrazide (3-MTPH), and 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-4-ylmethylene-hydrazide (4-MTPH) were synthesized and characterized. Corrosion inhibition performance of the prepared compounds on mild steel in 0.5 M HCl was studied using gravimetric, potentiodynamic polarisation, and electrochemical impedance techniques. Inhibition efficiency has direct relation with concentration and inverse relation with temperature. Thermodynamic parameters for dissolution and adsorption process were evaluated. Polarisation study reveals that compounds act as both anodic and cathodic inhibitors with emphasis on the former. Impedance study shows that decrease in charge transfer resistance is responsible for effective protection of steel surface by inhibitors. The film formed on the mild steel was investigated using FTIR, SEM, and EDX spectroscopy. Quantum chemical parameters likeEHOMO,ELUMO,ΔE, hardness, softness, and ionisation potential were calculated. Higher value ofEHOMOand lower value ofΔEindicate the better inhibition efficiency of the compounds. Lower ionisation potential of inhibitors indicates higher reactivity and lower chemical stability.

scholarly journals Impedimetric and Plasmonic Sensing of Collagen I Using a Half-Antibody-Supported, Au-Modified, Self-Assembled Monolayer System

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 227
Author(s):  
Marcin Gwiazda ◽  
Sheetal K. Bhardwaj ◽  
Ewa Kijeńska-Gawrońska ◽  
Wojciech Swieszkowski ◽  
Unni Sivasankaran ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Covalent Immobilization ◽  
Electrochemical Immunosensor ◽  
Collagen I ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type I ◽  
Self Assembled Monolayer ◽  
Self Assembled

This research presents an electrochemical immunosensor for collagen I detection using a self-assembled monolayer (SAM) of gold nanoparticles (AuNPs) and covalently immobilized half-reduced monoclonal antibody as a receptor; this allowed for the validation of the collagen I concentration through two different independent methods: electrochemically by Electrochemical Impedance Spectroscopy (EIS), and optically by Surface Plasmon Resonance (SPR). The high unique advantage of the proposed sensor is based on the performance of the stable covalent immobilization of the AuNPs and enzymatically reduced half-IgG collagen I antibodies, which ensured their appropriate orientation onto the sensor’s surface, good stability, and sensitivity properties. The detection of collagen type I was performed in a concentration range from 1 to 5 pg/mL. Moreover, SPR was utilized to confirm the immobilization of the monoclonal half-antibodies and sensing of collagen I versus time. Furthermore, EIS experiments revealed a limit of detection (LOD) of 0.38 pg/mL. The selectivity of the performed immunosensor was confirmed by negligible responses for BSA. The performed approach of the immunosensor is a novel, innovative attempt that enables the detection of collagen I with very high sensitivity in the range of pg/mL, which is significantly lower than the commonly used enzyme-linked immunosorbent assay (ELISA).

Covalent immobilization of dysprosium-based metal–organic chains on silicon-based polymer brush surfaces

2017 ◽  
Vol 41 (15) ◽  
pp. 7007-7011
Author(s):  
Ana Belén Ruiz-Muelle ◽  
Antonio Rodríguez-Diéguez ◽  
Rafael Contreras-Cáceres ◽  
Ignacio Fernández
Keyword(s):  
Carboxylic Acid ◽  
Acrylic Acid ◽  
Polymer Brushes ◽  
Polymer Brush ◽  
Covalent Immobilization ◽  
Sodium Ions ◽  
Metal Organic ◽  
Silicon Based ◽  
Poly Acrylic Acid

We report on a process for immobilizing metal–organic chains constructed of dysprosium and sodium ions based on 5-aminopyridine-2-carboxylic acid, onto silicon-based surfaces coated with poly(acrylic acid) (PAA) polymer brushes.

Electrochemical Impedance Study of GaAs Surface Charge Modulation through the Deprotonation of Carboxylic Acid Monolayers

Langmuir ◽  
2011 ◽  
Vol 27 (18) ◽  
pp. 11273-11277 ◽  
Author(s):  
Fernanda Camacho-Alanis ◽  
Homero Castaneda ◽  
Giovanni Zangari ◽  
Nathan S. Swami
Keyword(s):  
Carboxylic Acid ◽  
Surface Charge ◽  
Electrochemical Impedance ◽  
Gaas Surface ◽  
Impedance Study ◽  
Charge Modulation
Sign in / Sign up

Export Citation Format

Share Document