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Fritz PA, Boom RM, Schroën C. Electrochemically driven adsorptive separation techniques: From ions to proteins and cells in liquid streams. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118754] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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2
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Jin Z, He Q, Luo H, Pan Y, Sun C, Cai Z. The oxidation of cysteine-containing peptides caused by perfluoroalkane sulfonyl fluorides. JOURNAL OF HAZARDOUS MATERIALS 2020; 385:121564. [PMID: 31757724 DOI: 10.1016/j.jhazmat.2019.121564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/06/2019] [Accepted: 10/28/2019] [Indexed: 06/10/2023]
Abstract
Perfluorooctane sulfonyl fluoride (PFOSF) is the precursor of many fluorochemicals that are ubiquitous in the environment. However, its distribution and toxicology are rarely studied. In this work, the oxidability of PFOSF was found. PFOSF can accelerate oxidation of glutathione (GSH) to its oxidized form GSSG, and itself is reduced to a sulfinic acid. The yielded sulfinic acid was prepared and identified with high resolution mass spectrometry and NMR. Similar redox reactions were observed for PFOSF's short chain alternatives. The reduction potentials of perfluoroalkane sulfonyl fluorides (PFASFs) were determined to be -2.13 V vs. SCE with cyclic voltammetry, further demonstrating their oxidability. The peptide mixtures of GSH plus another cysteine-containing peptide were also oxidized by PFASFs to GSSG and an asymmetric disulfide GS-S-PEP. A single short-sequence PEP-SH could be oxidized to the symmetric disulfide PEP-S-S-PEP as the final product. In vitro experiments were carried out by adding PFASFs into rat liver S9 fractions. The turnover ratio of PFASFs were calculated to be about 4-10% by quantification of sulfinic acid with LC-MS/MS. Our work illustrates one of the potential metabolic pathways of PFASFs and demonstrates the oxidation of PEP-SHs by PFASFs, thus providing a preliminary exploration in the toxicology of these fluorochemicals.
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Affiliation(s)
- Zhe Jin
- College of Pharmaceutical Sciences, Zhejiang University, Zhejiang 310058, China; Department of Chemistry, Zhejiang University, Zhejiang 310027, China
| | - Quan He
- Department of Chemistry, Zhejiang University, Zhejiang 310027, China
| | - Haiwei Luo
- College of Pharmaceutical Sciences, Zhejiang University, Zhejiang 310058, China
| | - Yuanjiang Pan
- Department of Chemistry, Zhejiang University, Zhejiang 310027, China
| | - Cuirong Sun
- College of Pharmaceutical Sciences, Zhejiang University, Zhejiang 310058, China.
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong 999077, China.
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Yan C, Huang X, Chen J, Guo H, Shao H. Study on Preferential Solvation of Water by Electrochemical Method. ELECTROANAL 2019. [DOI: 10.1002/elan.201900243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Chunxia Yan
- Beijing Key Laboratory of Photoelectronic and Electrophotonic Conversion Materials, Key Laboratory of Cluster Science (Ministry of Education), School of Chemistry and Chemical EngineeringBeijing Institute of Technology Beijing 102488 P.R. China
| | - Ximing Huang
- Beijing Key Laboratory of Photoelectronic and Electrophotonic Conversion Materials, Key Laboratory of Cluster Science (Ministry of Education), School of Chemistry and Chemical EngineeringBeijing Institute of Technology Beijing 102488 P.R. China
| | - Jingchao Chen
- Beijing Key Laboratory of Photoelectronic and Electrophotonic Conversion Materials, Key Laboratory of Cluster Science (Ministry of Education), School of Chemistry and Chemical EngineeringBeijing Institute of Technology Beijing 102488 P.R. China
| | - Haixia Guo
- Beijing Key Laboratory of Photoelectronic and Electrophotonic Conversion Materials, Key Laboratory of Cluster Science (Ministry of Education), School of Chemistry and Chemical EngineeringBeijing Institute of Technology Beijing 102488 P.R. China
| | - Huibo Shao
- Beijing Key Laboratory of Photoelectronic and Electrophotonic Conversion Materials, Key Laboratory of Cluster Science (Ministry of Education), School of Chemistry and Chemical EngineeringBeijing Institute of Technology Beijing 102488 P.R. China
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Pounsamy M, Somasundaram S, Palanivel S, Balasubramani R, Chang SW, Nguyen DD, Ganesan S. A novel protease-immobilized carbon catalyst for the effective fragmentation of proteins in high-TDS wastewater generated in tanneries: Spectral and electrochemical studies. ENVIRONMENTAL RESEARCH 2019; 172:408-419. [PMID: 30826663 DOI: 10.1016/j.envres.2019.01.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/18/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
The aim of this study was to degrade proteins in high-total dissolved solids (TDS)-containing wastewater produced during the soaking process in tanneries (tannery-TDS wastewater) using a halotolerant protease-assisted nanoporous carbon catalyst (STPNPAC). A halotolerant protease was obtained from the halophile, Lysinibacillus macroides, using animal fleshing as the substrate. The protease was immobilized using ethylene diamine (EDA)/glutaraldehyde functionalized nanoporous activated carbon (EGNPAC). The optimum conditions for the immobilization of protease were determined as time (120 min), pH (6), protease concentration (575-600 U/g), EGNPAC size, salinity, and temperature (30 °C). The immobilization was confirmed by FTIR, TGA-DSC, SEM, and XRD analyses. The adsorption kinetics was consistent with a pseudo first order rate constant of 1.43 × 10-2 min-1. The thermodynamic parameters (ΔG, ΔH, and ΔS) confirmed the effective immobilization of the protease onto EGNPAC. STPNAPC was found to efficiently degrade the proteins in tannery-TDS wastewater, with a complete fragmentation time of 90 min at pH 6 and 30 °C. Accordingly, the protein fragmentation was confirmed by UV-visible and UV-fluorescence spectroscopy, ESI-mass spectrometric analysis and circular dichroic studies. The formation of protein hydrolysates was confirmed by cyclic voltammetry and electrical impedance studies. BOD5: COD value, 0.426 of treated tannery-TDS wastewater may favor sequential biological treatment processes.
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Affiliation(s)
- Maharaja Pounsamy
- Advanced Materials Laboratory, Council of Scientific & Industrial Research (CSIR) Central Leather Research Institute (CLRI), Adyar, Chennai 600 020, Tamilnadu, India; Environmental Science and Engineering Division, Council of Scientific & Industrial Research (CSIR) Central Leather Research Institute (CLRI), Adyar, Chennai 600 020, Tamilnadu, India
| | - Swarnalatha Somasundaram
- Environmental Science and Engineering Division, Council of Scientific & Industrial Research (CSIR) Central Leather Research Institute (CLRI), Adyar, Chennai 600 020, Tamilnadu, India
| | - Saravanan Palanivel
- Leather Process Technology Laboratory, Council of Scientific & Industrial Research (CSIR) Central Leather Research Institute (CLRI), Adyar, Chennai 600 020, Tamilnadu, India
| | - Ravindran Balasubramani
- Department of Environmental Energy and Engineering, Kyonggi University Youngtong-Gu, Suwon, Gyeonggi-Do 16227, South Korea.
| | - Soon Woong Chang
- Department of Environmental Energy and Engineering, Kyonggi University Youngtong-Gu, Suwon, Gyeonggi-Do 16227, South Korea
| | - Dinh Duc Nguyen
- Department of Environmental Energy and Engineering, Kyonggi University Youngtong-Gu, Suwon, Gyeonggi-Do 16227, South Korea; Institute of Research and Development, Duy Tan University, Da Nang, Vietnam
| | - Sekaran Ganesan
- Environmental Science and Engineering Division, Council of Scientific & Industrial Research (CSIR) Central Leather Research Institute (CLRI), Adyar, Chennai 600 020, Tamilnadu, India.
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Samanman S, Thammakhet C, Kanatharana P, Buranachai C, Thavarungkul P. Novel template-assisted fabrication of porous gold nanowire arrays using a conductive-layer-free anodic alumina oxide membrane. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.04.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sarakbi A, Aydogmus Z, Dago A, Mertens D, Dewert JY, Kauffmann JM. Determination of aminothiols by liquid chromatography with amperometric detection at a silver electrode: application to white wines. Anal Chim Acta 2013; 786:22-8. [PMID: 23790287 DOI: 10.1016/j.aca.2013.04.070] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/26/2013] [Accepted: 04/29/2013] [Indexed: 11/19/2022]
Abstract
Liquid chromatography coupled to a silver electrode based flow-through amperometric detector (LC-EC-Ag) was developed for the determination of aminothiols in white wines. The C18 reversed phase LC system operated in the isocratic mode at 0.7 mL min(-1) and used an acidic mobile phase composed of formic acid, EDTA, sodium nitrate, sodium hydroxide, and methanol 1% (v/v) at pH 4.5. The working electrode operated at 0.08 V vs Ag/AgCl, 3M KCl and its manual cleaning was realized once a month by smoothing on a polishing cloth. The analyzed aminothiols were resolved and eluted within 4 min, and all standard curves were linear in the range 2×10(-7)-2×10(-5) M. The analyzed wine samples needed no preparation other than dilution with the mobile phase. The concentration of cysteine (CYS), homocysteine (HCYS), glutathione (GSH) and N-acetylcysteine (NAC) in bottled white wines, determined by the method of standard addition, was found to be in the low μM range (0.2-2 mg L(-1)) depending on the wine type and its age.
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Affiliation(s)
- Ahmad Sarakbi
- Université Libre de Bruxelles, Faculty of Pharmacy, Brussels, Belgium
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Drug–GSH interaction on GSH–Au modified electrodes: A cyclic voltammetry and electrochemical impedance spectroscopy study. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.07.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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George S, Lee HK. Direct Electrochemistry and Electrocatalysis of Hemoglobin in Nafion/Carbon Nanochip Film on Glassy Carbon Electrode. J Phys Chem B 2009; 113:15445-54. [DOI: 10.1021/jp905690a] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sini George
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Hian Kee Lee
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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McEwen GD, Chen F, Zhou A. Immobilization, hybridization, and oxidation of synthetic DNA on gold surface: electron transfer investigated by electrochemistry and scanning tunneling microscopy. Anal Chim Acta 2009; 643:26-37. [PMID: 19446060 PMCID: PMC2754797 DOI: 10.1016/j.aca.2009.03.050] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 03/31/2009] [Accepted: 03/31/2009] [Indexed: 11/20/2022]
Abstract
Fundamental understanding of interfacial electron transfer (ET) among electrolyte/DNA/solid-surface will facilitate the design for electrical detection of DNA molecules. In this report, the electron transfer characteristics of synthetic DNA (sequence from pathogenic Cryptosporidium parvum) self-assembled on a gold surface was electrochemically studied. The effects of immobilization order on the interface ET related parameters such as diffusion coefficient (D0), surface coverage (thetaR), and monolayer thickness (d(i)) were determined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). DNA surface density (Gamma(DNA)) was determined by the integration of the charge of the electro-oxidation current peaks during the initial cyclic voltammetry scans. It was found that the DNA surface densities at different modifications followed the order: Gamma(DNA) (dsS-DNA/Au) > Gamma(DNA) (MCH/dsS-DNA/Au) > Gamma(DNA) (dsS-DNA/MCH/Au). It was also revealed that the electro-oxidation of the DNA modified gold surface would involve the oxidation of nucleotides (guanine and adenine) with a 5.51 electron transfer mechanism and the oxidative desorption of DNA and MCH molecules by a 3 electron transfer mechanism. STM topography and current image analysis indicated that the surface conductivity after each surface modification followed the order: dsS-DNA/Au < MCH/dsS-DNA/Au < oxidized MCH/dsS-DNA/Au < Hoechst/oxidized MCH/dsS-DNA/Au. The results from this study suggested a combination of variations in immobilization order may provide an alternative approach for the optimization of DNA hybridization and the further development for electrical detection of DNA.
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Affiliation(s)
- Gerald D. McEwen
- Biological Engineering Program, Department of Biological and Irrigation Engineering, Utah State University, Logan, Utah 84322-4105 USA
| | - Fan Chen
- Biological Engineering Program, Department of Biological and Irrigation Engineering, Utah State University, Logan, Utah 84322-4105 USA
| | - Anhong Zhou
- Biological Engineering Program, Department of Biological and Irrigation Engineering, Utah State University, Logan, Utah 84322-4105 USA
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10
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Application of electrochemical properties of ordered mesoporous carbon to the determination of glutathione and cysteine. Anal Biochem 2009; 386:79-84. [DOI: 10.1016/j.ab.2008.11.041] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 11/21/2008] [Accepted: 11/26/2008] [Indexed: 11/22/2022]
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11
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Yang J, Pang F, Zhang R, Xu Y, He P, Fang Y. Electrochemistry and Electrocatalysis of Hemoglobin on 1-Pyrenebutanoic Acid Succinimidyl Ester/Multiwalled Carbon Nanotube and Au Nanoparticle Modified Electrode. ELECTROANAL 2008. [DOI: 10.1002/elan.200804298] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Potucek RK, Sumar A, Vanýsek P, Birss VI. Data correction technique for using common electrochemical apparatus for the measurement of crystal impedance. Electrochim Acta 2007. [DOI: 10.1016/j.electacta.2007.06.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Bieri M, Gautier C, Bürgi T. Probing chiral interfaces by infrared spectroscopic methods. Phys Chem Chem Phys 2007; 9:671-85. [PMID: 17268678 DOI: 10.1039/b609930k] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biological homochirality on earth and its tremendous consequences for pharmaceutical science and technology has led to an ever increasing interest in the selective production, the resolution and the detection of enantiomers of a chiral compound. Chiral surfaces and interfaces that can distinguish between enantiomers play a key role in this respect as enantioselective catalysts as well as for separation purposes. Despite the impressive progress in these areas in the last decade, molecular-level understanding of the interactions that are at the origin of enantiodiscrimination are lagging behind due to the lack of powerful experimental techniques to spot these interactions selectively with high sensitivity. In this article, techniques based on infrared spectroscopy are highlighted that are able to selectively target the chiral properties of interfaces. In particular, these methods are the combination of Attenuated Total Reflection InfraRed (ATR-IR) with Modulation Excitation Spectroscopy (MES) to probe enantiodiscriminating interactions at chiral solid-liquid interfaces and Vibrational Circular Dichroism (VCD), which is used to probe the structure of chirally-modified metal nanoparticles. The former technique aims at suppressing signals arising from non-selective interactions, which may completely hide the signals of interest due to enantiodiscriminating interactions. Recently, this method was successfully applied to investigate enantiodiscrimination at self-assembled monolayers of chiral thiols on gold surfaces. The nanometer size analogues of the latter--gold nanoparticles protected by a monolayer of a chiral thiol--are amenable to VCD spectroscopy. It is shown that this technique yields detailed structural information on the adsorption mode and the conformation of the adsorbed thiol. This may also turn out to be useful to clarify how chirality can be bestowed onto the metal core itself and the nature of the chirality of the latter, which is manifested in the metal-based circular dichroism activity of these nanoparticles.
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Affiliation(s)
- Marco Bieri
- Université de Neuchâtel, Institut de Microtechnique, Laboratoire de Chimie Physique des Surfaces, Rue Emile-Argand 11, 2009, Neuchâtel, Switzerland
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Herzog G, Arrigan DWM. Electrochemical strategies for the label-free detection of amino acids, peptides and proteins. Analyst 2007; 132:615-32. [PMID: 17592579 DOI: 10.1039/b701472d] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrochemical methods for the detection of amino acids, peptides, and proteins in a variety of media are reviewed. Label-free strategies in which the detection is based on the inherent electrochemical properties of the analyte are discussed. Various processes such as direct or mediated (in solution or immobilised) redox processes and interfacial ion transfers have been employed for the electrochemical detection and determination of the target analytes. The various methods covered encompass voltammetry at uncoated and modified electrodes and at immiscible liquid-liquid interfaces, potentiometry at polymer membrane electrodes and electrochemical impedance spectroscopy. The determination of the target analytes in complex biological matrices is discussed. The various approaches highlighted here illustrate the rich capabilities of electrochemical methods as simple, low-cost, sensitive tools for the determination of these important biological analytes at trace and ultra-trace levels.
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Affiliation(s)
- Grégoire Herzog
- Tyndall National Institute, Lee Maltings, University College, Cork, Ireland
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Tang H, Chen J, Nie L, Yao S, Kuang Y. Electrochemical oxidation of glutathione at well-aligned carbon nanotube array electrode. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2005.08.038] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bieri M, Bürgi T. Adsorption Kinetics, Orientation, and Self-Assembling of N-Acetyl-l-cysteine on Gold: A Combined ATR-IR, PM-IRRAS, and QCM Study. J Phys Chem B 2005; 109:22476-85. [PMID: 16853928 DOI: 10.1021/jp052409m] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The adsorption of N-acetyl-L-cysteine from ethanol solution on gold has been studied by in situ attenuated total reflection infrared (ATR-IR) spectroscopy, polarization modulation infrared reflection absorption spectroscopy, and a quartz crystal microbalance. After an initial fast adsorption, in situ ATR-IR revealed two considerably slower processes, besides further adsorption. The appearance of carboxylate bands and the partial disappearance of the carboxylic acid bands demonstrated that part of the molecules on the surface underwent deprotonation. In addition, the C=O stretching vibration of the carboxylic acid group shifted to lower and the amide II band to higher wavenumbers, indicating hydrogen-bonding interactions within the adsorbate layer. Based on the initial ATR-IR spectrum, which did not reveal deprotonation, the orientation of the molecule within the adsorbate layer was determined. For this, density functional theory was used to calculate the transition dipole moment vectors of the vibrational modes of N-acetyl-l-cysteine. The projections of the latter onto the z-axis of the fixed surface coordinate system were used to determine relative band intensities for different orientations of the molecule. The analysis revealed that the amide group is tilted with respect to and points away from the surface, whereas the carboxylic acid is in proximity to the surface, which is also supported by a shift of the C-O-H bending mode. This position of the acid group favors its deprotonation assisted by the gold surface and easily enables intermolecular interactions. Periodic acid stimuli revealed reversible protonation/deprotonation of part of the adsorbed molecules. However, only non-hydrogen-bonded carboxylic acid groups showed a response toward the acid stimuli.
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Affiliation(s)
- Marco Bieri
- Institut de Chimie, Université de Neuchâtel, Rue Emile-Argand 11, 2007- Neuchâtel, Switzerland
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Bieri M, Bürgi T. L-glutathione chemisorption on gold and acid/base induced structural changes: a PM-IRRAS and time-resolved in situ ATR-IR spectroscopic study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:1354-63. [PMID: 15697281 DOI: 10.1021/la047735s] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Adsorption of the tripeptide L-glutathione (gamma-glu-cys-gly) on gold surfaces was investigated by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) and attenuated total reflection (ATR) infrared spectroscopy. PM-IRRAS was used to study ex situ the adsorbate layer prepared from aqueous solutions at different pH, whereas ATR-IR was applied to study in situ adsorption from ethanol in the presence and absence of acid and base. ATR-IR was furthermore combined with modulation spectroscopy in order to investigate the reversible changes within the adsorbate layer induced by acid and base stimuli, respectively. The molecule is firmly anchored on the gold surface via the thiol group of the cys part. However, the ATR-IR spectra in ethanol indicate a further interaction with the gold surface via the carboxylic acid group of the gly part of the molecule, which deprotonates upon adsorption. Hydrochloric acid readily protonates the two acid groups of the adsorbed molecule. During subsequent ethanol flow the acid groups deprotonate again, a process which proceeds in two distinct steps: a fast step associated with the deprotonation of the acid in the glu part of the molecule and a considerably slower step associated with deprotonation of the acid in the gly moiety. The latter process is assisted by the interaction of the corresponding acid group with the surface. The spectra furthermore indicate a rearrangement of the hydrogen bonding network within the adsorbate layer upon deprotonation. Depending on the protonation state during adsorption of l-glutathione, the response toward identical protonation-deprotonation stimuli is significantly different. This is explained by the ionic state-dependent shape of the molecule, as supported by density functional theory calculations. The different shapes of the individual molecules during layer formation thus influence the structure of the adsorbate layer.
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Affiliation(s)
- Marco Bieri
- Institut de Chimie, Faculté des Sciences, Université de Neuchâtel, Rue Emile-Argand 11, 2007 Neuchâtel, Switzerland
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Kleijn JM, Barten D, Stuart MAC. Adsorption of charged macromolecules at a gold electrode. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:9703-9713. [PMID: 15491205 DOI: 10.1021/la049656m] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Using an optical reflectometer with impinging-jet system, the adsorption from aqueous solution onto gold of three charged macromolecules has been studied: the strong linear-chain polyelectrolyte polyvinyl pyridine (PVP(+)), the fifth-generation poly(propylene imine) dendrimer DAB-64, which has a pH-dependent charge and a relatively fixed shape, and the protein lysozyme, of which both the charge and the structure-stability are dependent on solution composition. Experimental conditions that have been varied include the adsorbate concentration, electrolyte concentration, pH, and externally applied potential across the gold/solution interface. Making use of the earlier established dependency of the double layer potential of the gold substrate on solution conditions and externally applied potential, the results of measurements as a function of pH and as a function of external potential control are compared. The total set of results enables us to draw conclusions with respect to the relative importance of electrostatic interactions for the adsorption process. PVP(+) adsorption follows the electric potential of the gold/solution interface and is further determined by a rather strong nonelectrostatic affinity between segments and surface. The adsorption behavior of DAB-64 is not quite understood, but electrostatic interactions with the gold surface seem to play a minor role. For lysozyme, surface-induced conformational changes dominate the adsorption process. The extent of spreading of the molecules decreases with increasing polarity of the surface, resulting in a minimum in adsorbed amount around the point of zero potential of the gold.
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Affiliation(s)
- J Mieke Kleijn
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University, P.O. Box 8038, 6700 EK Wageningen, The Netherlands.
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Diniz FB, Ueta RR, Pedrosa AMDC, Areias MDC, Pereira VRA, Silva ED, da Silva JG, Ferreira AGP, Gomes YM. Impedimetric evaluation for diagnosis of Chagas’ disease: antigen–antibody interactions on metallic eletrodes. Biosens Bioelectron 2003; 19:79-84. [PMID: 14568706 DOI: 10.1016/s0956-5663(03)00213-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A polypeptide chain formed by recombinant antigens, cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA) (CF-Chimera) of Trypanosoma cruzi, was adsorbed on gold and platinum electrodes and investigated by electrochemical impedance spectroscopy on phosphate buffer saline solutions (PBS) containing a redox couple. It was found that the adsorption is strongly sensitive to the oxide layer on the electrode surface. In the majority of the experiments the antigens retained their activity as observed through their interaction with sera from chronic chagasic patients. The results expressed in terms of the charge transfer resistance across the interface, indicate the viability of using the impedance methodology for the development of a biosensor for serological diagnosis of Chagas' disease.
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Affiliation(s)
- Flamarion B Diniz
- Laboratório de Eletroquímica, Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife, PE, Brazil.
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Study on the influence of anionic and cationic surfactant on Au-colloid modified electrode function by cyclic voltammetry and electrochemical impedance techniques. Electrochim Acta 2003. [DOI: 10.1016/s0013-4686(03)00423-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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