1
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Kim SM, Chang YR, Lee YJ. Single-detector double-beam modulation for high-sensitivity infrared spectroscopy. Sci Rep 2023; 13:18231. [PMID: 37880230 PMCID: PMC10600177 DOI: 10.1038/s41598-023-44740-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 10/11/2023] [Indexed: 10/27/2023] Open
Abstract
Balanced detection based on double beams is widely used to reduce common-mode noises, such as laser intensity fluctuation and irregular wavelength scanning, in absorption spectroscopy. However, employing an additional detector can increase the total system noise due to added non-negligible thermal noise of the detector, particularly with mid-infrared (IR) detectors. Herein, we demonstrate a new optical method based on double-beam modulation (DBM) that uses a single-element detector but keeps the advantage of double-beam balanced detection. The sample and reference path beams were modulated out-of-phase with each other at a high frequency, and their average and difference signals were measured by two lock-in amplifiers and converted into absorbance. DBM was coupled with our previously reported solvent absorption compensation (SAC) method to eliminate the IR absorption contribution of water in aqueous solutions. The DBM-SAC method enabled us to acquire IR absorption spectra of bovine serum albumin solutions down to 0.02 mg/mL. We investigated the noise characteristics of DBM measurements when the wavelength was either fixed or scanned. The results demonstrate that DBM can lower the limit of detection by ten times compared to the non-modulation method.
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Affiliation(s)
- Seong-Min Kim
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Yow-Ren Chang
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Young Jong Lee
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
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2
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Morhart TA, Tu K, Read ST, Rosendahl SM, Wells G, Achenbach S, Burgess IJ. Surface enhanced infrared spectroelectrochemistry using a microband electrode. CAN J CHEM 2021. [DOI: 10.1139/cjc-2021-0183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The successful use of a microband electrode printed on a silicon internal reflection element to perform time resolved infrared spectroscopy is described. Decreasing the critical dimension of the microband electrode to several hundred micrometers provides a sub-microsecond time constant in a Kretschmann configured spectroelectrochemical cell. The high brilliance of synchrotron sourced infrared radiation has been combined with a specially designed horizontal attenuated total reflectance (ATR) microscope to focus the infrared beam on the microband electrode. The first use of a sub-microsecond time constant working electrode for ATR surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) is reported. Measurements show that the advantage afforded by the high brilliance of the synchrotron source is at least partially offset by increased noise from the experimental floor. The test system was the potential induced desorption of an adsorbed monolayer of 4-methoxypyridine (MOP) as measured using step-scan interferometry. Based on diffusion considerations alone, the expected time scale of the process was less than 10 microseconds but was experimentally measured to be three orders of magnitude slower. A defect-mediated dissolution of the condensed film is speculated to be the underlying cause of the unexpected slow kinetics.
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Affiliation(s)
- Tyler A. Morhart
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
- Canadian Light Source, Saskatoon, SK S7N 0X4, Canada
| | - Kaiyang Tu
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
- Canadian Light Source, Saskatoon, SK S7N 0X4, Canada
| | | | | | - Garth Wells
- Canadian Light Source, Saskatoon, SK S7N 0X4, Canada
| | - Sven Achenbach
- Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada
| | - Ian J. Burgess
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
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3
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Ash PA, Kendall-Price SET, Evans RM, Carr SB, Brasnett AR, Morra S, Rowbotham JS, Hidalgo R, Healy AJ, Cinque G, Frogley MD, Armstrong FA, Vincent KA. The crystalline state as a dynamic system: IR microspectroscopy under electrochemical control for a [NiFe] hydrogenase. Chem Sci 2021; 12:12959-12970. [PMID: 34745526 PMCID: PMC8514002 DOI: 10.1039/d1sc01734a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/03/2021] [Indexed: 12/24/2022] Open
Abstract
Controlled formation of catalytically-relevant states within crystals of complex metalloenzymes represents a significant challenge to structure-function studies. Here we show how electrochemical control over single crystals of [NiFe] hydrogenase 1 (Hyd1) from Escherichia coli makes it possible to navigate through the full array of active site states previously observed in solution. Electrochemical control is combined with synchrotron infrared microspectroscopy, which enables us to measure high signal-to-noise IR spectra in situ from a small area of crystal. The output reports on active site speciation via the vibrational stretching band positions of the endogenous CO and CN- ligands at the hydrogenase active site. Variation of pH further demonstrates how equilibria between catalytically-relevant protonation states can be deliberately perturbed in the crystals, generating a map of electrochemical potential and pH conditions which lead to enrichment of specific states. Comparison of in crystallo redox titrations with measurements in solution or of electrode-immobilised Hyd1 confirms the integrity of the proton transfer and redox environment around the active site of the enzyme in crystals. Slowed proton-transfer equilibria in the hydrogenase in crystallo reveals transitions which are only usually observable by ultrafast methods in solution. This study therefore demonstrates the possibilities of electrochemical control over single metalloenzyme crystals in stabilising specific states for further study, and extends mechanistic understanding of proton transfer during the [NiFe] hydrogenase catalytic cycle.
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Affiliation(s)
- Philip A Ash
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
- School of Chemistry, University of Leicester Leicester LE1 7RH UK
- Leicester Institute of Structural and Chemical Biology, University of Leicester LE1 7RH UK
| | - Sophie E T Kendall-Price
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Rhiannon M Evans
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Stephen B Carr
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus Didcot UK
| | - Amelia R Brasnett
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Simone Morra
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Jack S Rowbotham
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Ricardo Hidalgo
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Adam J Healy
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Gianfelice Cinque
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0QX UK
- Department of Engineering Sciences, University of Oxford Parks Road Oxford OX1 3PJ UK
| | - Mark D Frogley
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0QX UK
| | - Fraser A Armstrong
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
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4
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Land H, Senger M, Berggren G, Stripp ST. Current State of [FeFe]-Hydrogenase Research: Biodiversity and Spectroscopic Investigations. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01614] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Henrik Land
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
| | - Moritz Senger
- Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
| | - Sven T. Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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5
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Lozeman JJA, Führer P, Olthuis W, Odijk M. Spectroelectrochemistry, the future of visualizing electrode processes by hyphenating electrochemistry with spectroscopic techniques. Analyst 2020; 145:2482-2509. [DOI: 10.1039/c9an02105a] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reviewing the future of electrochemistry combined with infrared, Raman, and nuclear magnetic resonance spectroscopy as well as mass spectrometry.
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Affiliation(s)
- Jasper J. A. Lozeman
- BIOS Lab-on-a-Chip Group
- MESA+ Institute
- University of Twente
- 7522 NB Enschede
- The Netherlands
| | - Pascal Führer
- BIOS Lab-on-a-Chip Group
- MESA+ Institute
- University of Twente
- 7522 NB Enschede
- The Netherlands
| | - Wouter Olthuis
- BIOS Lab-on-a-Chip Group
- MESA+ Institute
- University of Twente
- 7522 NB Enschede
- The Netherlands
| | - Mathieu Odijk
- BIOS Lab-on-a-Chip Group
- MESA+ Institute
- University of Twente
- 7522 NB Enschede
- The Netherlands
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6
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Ash PA, Kendall-Price SET, Vincent KA. Unifying Activity, Structure, and Spectroscopy of [NiFe] Hydrogenases: Combining Techniques To Clarify Mechanistic Understanding. Acc Chem Res 2019; 52:3120-3131. [PMID: 31675209 DOI: 10.1021/acs.accounts.9b00293] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Achieving a unified understanding of the mechanism of a multicenter redox enzyme such as [NiFe] hydrogenase is complicated by difficulties in reconciling information obtained by using different techniques and on samples in different physical forms. Measurements of the activity of the enzyme, and of factors which perturb activity, are generally carried out using biochemical assays in solution or with electrode-immobilized enzymes using protein film electrochemistry (PFE). Conversely, spectroscopy aimed at reporting on features of the metalloclusters in the enzyme, such as electron paramagnetic resonance (EPR) or X-ray absorption spectroscopy (XAS), is often conducted on frozen samples and is thus difficult to relate to catalytically relevant states as information about turnover and activity has been lost. To complicate matters further, most of our knowledge of the atomic-level structure of metalloenzymes comes from X-ray diffraction studies in the solid, crystalline state, which are again difficult to link to turnover conditions. Taking [NiFe] hydrogenases as our case study, we show here how it is possible to apply infrared (IR) spectroscopic sampling approaches to unite direct spectroscopic study with catalytic turnover. Using a method we have named protein film IR electrochemistry (PFIRE), we reveal the steady-state distribution of intermediates during catalysis and identify catalytic "bottlenecks" introduced by site-directed mutagenesis. We also show that it is possible to study dynamic transitions between active site states of enzymes in single crystals, uniting solid state and solution spectroscopic information. In all of these cases, the spectroscopic data complement and enhance interpretation of purely activity-based measurements by providing direct chemical insight that is otherwise hidden. The [NiFe] hydrogenases possess a bimetallic [NiFe] active site, coordinated by CO and CN- ligands, linked to the protein via bridging and terminal cysteine sulfur ligands, as well as an electron relay chain of iron sulfur clusters. Infrared spectroscopy is ideal for probing hydrogenases because the CO and CN- ligands are strong IR absorbers, but the suite of IR-based approaches we describe here will be equally valuable in studying substrate- or intermediate-bound states of other metalloenzymes where key mechanistic questions remain open, such as nitrogenase, formate dehydrogenase, or carbon monoxide dehydrogenase. We therefore hope that this Account will encourage future studies which unify information from different techniques across bioinorganic chemistry.
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Affiliation(s)
- Philip A. Ash
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | | | - Kylie A. Vincent
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
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7
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Morhart TA, Read S, Wells G, Jacobs M, Rosendahl SM, Achenbach S, Burgess IJ. Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectromicroscopy Using Synchrotron Radiation and Micromachined Silicon Wafers for Microfluidic Applications. APPLIED SPECTROSCOPY 2018; 72:1781-1789. [PMID: 29893584 DOI: 10.1177/0003702818785640] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A custom-designed optical configuration compatible with the use of micromachined multigroove internal reflection elements (μ-groove IREs) for attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy and imaging applications in microfluidic devices is described. The μ-groove IREs consist of several face-angled grooves etched into a single, monolithic silicon chip. The optical configuration permits individual grooves to be addressed by focusing synchrotron sourced IR light through a 150 µm pinhole aperture, restricting the beam spot size to a dimension smaller than that of the groove walls. The effective beam spot diameter at the ATR sampling plane is determined through deconvolution of the measured detector response and found to be 70 µm. The μ-groove IREs are highly compatible with standard photolithographic techniques as demonstrated by printing a 400 µm wide channel in an SU-8 film spin-coated on the IRE surface. Attenuated total reflection FT-IR mapping as a function of sample position across the channel illustrates the potential application of this approach for rapid prototyping of microfluidic devices.
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Affiliation(s)
- Tyler A Morhart
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Stuart Read
- Canadian Light Source, Saskatoon, SK, Canada
| | - Garth Wells
- Canadian Light Source, Saskatoon, SK, Canada
| | | | | | - Sven Achenbach
- Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ian J Burgess
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK, Canada
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8
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Liang Y, Cai R, Hickey DP, Kitt JP, Harris JM, Minteer SD, Korzeniewski C. Infrared Microscopy as a Probe of Composition within a Model Biofuel Cell Electrode Prepared from
Trametes versicolor
Laccase. ChemElectroChem 2018. [DOI: 10.1002/celc.201801178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Ying Liang
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409-1061 USA
| | - Rong Cai
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - David P. Hickey
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - Jay P. Kitt
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - Joel M. Harris
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | | | - Carol Korzeniewski
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409-1061 USA
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
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9
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Luo W, Arhatari B, Gray SR, Xie M. Seeing is believing: Insights from synchrotron infrared mapping for membrane fouling in osmotic membrane bioreactors. WATER RESEARCH 2018; 137:355-361. [PMID: 29574245 DOI: 10.1016/j.watres.2018.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/16/2018] [Accepted: 03/05/2018] [Indexed: 06/08/2023]
Abstract
We employed synchrotron infrared (IR) mapping to resolve forward osmosis (FO) membrane fouling in osmotic membrane bioreactor (OMBR). Synchrotron IR mapping offers a unique perspective to elucidate the fouling mechanisms and associated consequences in OMBR operation. We demonstrated the spatial distribution and relative intensity of carbohydrate and protein longitudinally along of the fouled FO membrane at the conclusion of OMBR operation. Both transmission and attenuated total reflection (ATR) modes were used to map the cross-section and surface of the fouled FO membrane. Micro X-ray computed tomography revealed patchy, "sand-dune" features on the membrane surface at the conclusion of OMBR operation. Synchrotron IR-ATR mapping demonstrated that the development of membrane fouling layer in OMBR operation was initiated by polysaccharide-like carbohydrate, followed by layering with protein-like substance, resulting in a characteristic "sand-dune" three dimensional feature. Synchrotron FTIR mapping shed light on foulant occurrence and accumulation in the draw solution. Strong penetration of protein-like substance into membrane matrix was visualised, resulting the detection of protein adsorption in the region of membrane supporting layer.
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Affiliation(s)
- Wenhai Luo
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
| | - Benedicta Arhatari
- ARC Centre of Excellence for Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe University, Victoria 3086, Australia
| | - Stephen R Gray
- Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria 8001, Australia
| | - Ming Xie
- Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria 8001, Australia.
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10
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Ash PA, Carr SB, Reeve HA, Skorupskaitė A, Rowbotham JS, Shutt R, Frogley MD, Evans RM, Cinque G, Armstrong FA, Vincent KA. Generating single metalloprotein crystals in well-defined redox states: electrochemical control combined with infrared imaging of a NiFe hydrogenase crystal. Chem Commun (Camb) 2018; 53:5858-5861. [PMID: 28504793 PMCID: PMC5708527 DOI: 10.1039/c7cc02591b] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We describe an approach to generating and verifying well-defined redox states in metalloprotein single crystals by combining electrochemical control with synchrotron infrared microspectroscopic imaging. For NiFe hydrogenase 1 from Escherichia coli we demonstrate fully reversible and uniform electrochemical reduction from the oxidised inactive to the fully reduced state, and temporally resolve steps during this reduction.
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Affiliation(s)
- P A Ash
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - S B Carr
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK and Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - H A Reeve
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - A Skorupskaitė
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - J S Rowbotham
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - R Shutt
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - M D Frogley
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, UK
| | - R M Evans
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - G Cinque
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, UK
| | - F A Armstrong
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - K A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
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11
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Ash PA, Hidalgo R, Vincent KA. Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase. J Vis Exp 2017:55858. [PMID: 29286464 PMCID: PMC5755520 DOI: 10.3791/55858] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Understanding the chemistry of redox proteins demands methods that provide precise control over redox centers within the protein. The technique of protein film electrochemistry, in which a protein is immobilized on an electrode surface such that the electrode replaces physiological electron donors or acceptors, has provided functional insight into the redox reactions of a range of different proteins. Full chemical understanding requires electrochemical control to be combined with other techniques that can add additional structural and mechanistic insight. Here we demonstrate a technique, protein film infrared electrochemistry, which combines protein film electrochemistry with infrared spectroscopic sampling of redox proteins. The technique uses a multiple-reflection attenuated total reflectance geometry to probe a redox protein immobilized on a high surface area carbon black electrode. Incorporation of this electrode into a flow cell allows solution pH or solute concentrations to be changed during measurements. This is particularly powerful in addressing redox enzymes, where rapid catalytic turnover can be sustained and controlled at the electrode allowing spectroscopic observation of long-lived intermediate species in the catalytic mechanism. We demonstrate the technique with experiments on E. coli hydrogenase 1 under turnover (H2 oxidation) and non-turnover conditions.
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Affiliation(s)
- Philip A Ash
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory
| | - Ricardo Hidalgo
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory;
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12
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Lardner MJ, Tu K, Barlow BC, Rosendahl SM, Borondics F, Burgess IJ. Quantitative analysis of electrochemical diffusion layers using synchrotron infrared radiation. J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2016.12.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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13
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Xie M, Luo W, Gray SR. Synchrotron Fourier transform infrared mapping: A novel approach for membrane fouling characterization. WATER RESEARCH 2017; 111:375-381. [PMID: 28110141 DOI: 10.1016/j.watres.2017.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 06/06/2023]
Abstract
We described a synchrotron-based infrared (IR) microscopic method to characterize fouling layer induced by organic foulants and colloidal silica in membrane distillation (MD). This technique, utilizing the ultrahigh brightness of synchrotron infrared source, enables spectra with high signal-to-noise ratio that was obtained from micrometer-sized samples. Our results showed that synchrotron IR mapping was able to resolve the foulant spatial distribution in combined fouling in MD. Synchrotron IR mapping showed the spatial distribution of binary foulant (i.e., colloidal silica with alginate, bovine serum albumin (BSA) or humic acid, respectively) of the cross-section of MD membrane fouling layer. The well-resolved synchrotron IR mapping is also able to quantify the foulant distribution along the cross-section of the fouled MD membrane, providing detailed information regarding the transport and accumulation of specific foulant, which is of paramount importance to elucidate fouling mechanisms. Our results demonstrated that the synchrotron IR mapping method was a powerful method and had significant potential for both qualitative and quantitative characterization of membrane fouling layer.
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Affiliation(s)
- Ming Xie
- Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia.
| | - Wenhai Luo
- College of Resource and Environmental Science, China Agricultural University, Beijing, 100193, China
| | - Stephen R Gray
- Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia
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14
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Reeve HA, Ash PA, Park H, Huang A, Posidias M, Tomlinson C, Lenz O, Vincent KA. Enzymes as modular catalysts for redox half-reactions in H2-powered chemical synthesis: from biology to technology. Biochem J 2017; 474:215-230. [PMID: 28062838 PMCID: PMC5298933 DOI: 10.1042/bcj20160513] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/11/2016] [Accepted: 11/15/2016] [Indexed: 11/17/2022]
Abstract
The present study considers the ways in which redox enzyme modules are coupled in living cells for linking reductive and oxidative half-reactions, and then reviews examples in which this concept can be exploited technologically in applications of coupled enzyme pairs. We discuss many examples in which enzymes are interfaced with electronically conductive particles to build up heterogeneous catalytic systems in an approach which could be termed synthetic biochemistry We focus on reactions involving the H+/H2 redox couple catalysed by NiFe hydrogenase moieties in conjunction with other biocatalysed reactions to assemble systems directed towards synthesis of specialised chemicals, chemical building blocks or bio-derived fuel molecules. We review our work in which this approach is applied in designing enzyme-modified particles for H2-driven recycling of the nicotinamide cofactor NADH to provide a clean cofactor source for applications of NADH-dependent enzymes in chemical synthesis, presenting a combination of published and new work on these systems. We also consider related photobiocatalytic approaches for light-driven production of chemicals or H2 as a fuel. We emphasise the techniques available for understanding detailed catalytic properties of the enzymes responsible for individual redox half-reactions, and the importance of a fundamental understanding of the enzyme characteristics in enabling effective applications of redox biocatalysis.
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Affiliation(s)
- Holly A Reeve
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, U.K
| | - Philip A Ash
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, U.K
| | - HyunSeo Park
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, U.K
| | - Ailun Huang
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, U.K
| | - Michalis Posidias
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, U.K
| | - Chloe Tomlinson
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, U.K
| | - Oliver Lenz
- Department of Chemistry, Technische Universität Berlin, Berlin 10623, Germany
| | - Kylie A Vincent
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, U.K.
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15
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Morhart TA, Quirk A, Lardner MJ, May TE, Rosendahl SM, Burgess IJ. Femtomole Infrared Spectroscopy at the Electrified Metal–Solution Interface. Anal Chem 2016; 88:9351-9354. [DOI: 10.1021/acs.analchem.6b02840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tyler A. Morhart
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Amanda Quirk
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Michael J. Lardner
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Tim E. May
- Canadian Light Source, Saskatoon, Saskatchewan S7N 2 V3, Canada
| | | | - Ian J. Burgess
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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