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Zapanta MJ, Chen X, Van de Walle D, Postelmans A, Dewettinck K, Saeys W. Terahertz time-domain transmission spectroscopy of water and hydrogel thin films: Extraction of optical parameters and application to agarose gel characterization. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 320:124563. [PMID: 38861828 DOI: 10.1016/j.saa.2024.124563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/01/2024] [Accepted: 05/28/2024] [Indexed: 06/13/2024]
Abstract
Terahertz time-domain spectroscopy (THz-TDS) is an emerging optical technique that has potential applications in the characterization of (bio)materials. However, the complicated extraction of optical parameters from multi-layered and optically thin samples is a barrier towards its acceptance by applied scientists. Therefore, the aim of this work is to provide a straightforward approach for the extraction of the THz absorption coefficient and index of refraction profiles of aqueous thin films in a window-sample-window configuration, which is ubiquitous in many laboratories (i.e., sample in a cuvette). A numerical approach-based methodology that accounts for multiple layers, Fabry-Pérot effect, and sample thickness is elaborated which involves an optical interference model based on a tri-layer structure and a simple thickness estimation technique. This method was validated on water samples where a good agreement was found with the THz optical parameters of water reported in the literature, while the use of a commercial software resulted in erroneous optical parameters estimates when used without due regard to its limitations. A case study was then performed to demonstrate the ability of the proposed method to characterize agarose hydrogels with varying degree of sulfation. It was demonstrated that THz-TDS can provide insight into the hydration state of the agarose hydrogels, including the relative number of the hydrogen bonds between the hydroxyl moieties of water and the polysaccharide network which is perturbed by the presence of sulfate. The trend in the index of refraction profiles suggested microstructural differences between the agarose hydrogels, which were confirmed by visualizing the agarose network morphology using cryo-SEM imaging.
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Affiliation(s)
- Mark Justine Zapanta
- KU Leuven, Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium
| | - Xuequan Chen
- GBA Branch of Aerospace Information Research Institute, Chinese Academy of Sciences, 510530 Guangzhou, China
| | - Davy Van de Walle
- Ghent University, Department of Food Technology, Safety and Health, Food Structure and Function Research Group, Coupure Links 653, 9000 Ghent, Belgium
| | - Annelies Postelmans
- KU Leuven, Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium
| | - Koen Dewettinck
- Ghent University, Department of Food Technology, Safety and Health, Food Structure and Function Research Group, Coupure Links 653, 9000 Ghent, Belgium
| | - Wouter Saeys
- KU Leuven, Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
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Shi S, Yuan S, Zhou J, Jiang P. Terahertz technology and its applications in head and neck diseases. iScience 2023; 26:107060. [PMID: 37534152 PMCID: PMC10391736 DOI: 10.1016/j.isci.2023.107060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023] Open
Abstract
The terahertz (THz) radiation refers to electromagnetic waves between infrared and millimeter waves. THz technology has shown a significant potential for medical diagnosis and biomedical applications over the past three decades. Therefore, exploring the biological effects of THz waves has become an important new field in life sciences. Specifically, THz radiation has been proved to be able to diagnose and treat several head and neck diseases. In this review, we primarily discuss the biological characteristics of THz waves and clinical applications of THz technology, focusing on the research progress of THz technology in head and neck diseases (brain cancer, hypopharyngeal cancer, oral diseases, thyroid nodules, Alzheimer's disease, eyes diseases, and otitis). The future application perspectives of THz technologies in head and neck diseases are also highlighted and proposed.
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Affiliation(s)
- Shenggan Shi
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Shuqin Yuan
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Jun Zhou
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China
| | - Peidu Jiang
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
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Kawasaki T, Zen H, Ozaki K, Yamada H, Wakamatsu K, Ito S. Application of mid-infrared free-electron laser for structural analysis of biological materials. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:28-35. [PMID: 33399549 DOI: 10.1107/s160057752001406x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/21/2020] [Indexed: 06/12/2023]
Abstract
A mid-infrared free-electron laser (MIR-FEL) is a synchrotron-radiation-based femto- to pico-second pulse laser. It has unique characteristics such as variable wavelengths in the infrared region and an intense pulse energy. So far, MIR-FELs have been utilized to perform multi-photon absorption reactions against various gas molecules and protein aggregates in physical chemistry and biomedical fields. However, the applicability of MIR-FELs for the structural analysis of solid materials is not well recognized in the analytical field. In the current study, an MIR-FEL is applied for the first time to analyse the internal structure of biological materials by using fossilized inks from cephalopods as the model sample. Two kinds of fossilized inks that were collected from different strata were irradiated at the dry state by tuning the oscillation wavelengths of the MIR-FEL to the phosphoryl stretching mode of hydroxyapatite (9.6 µm) and to the carbonyl stretching mode of melanin (5.8 µm), and the subsequent structural changes in those materials were observed by using infrared microscopy and far-infrared spectroscopy. The structural variation of these biological fossils is discussed based on the infrared-absorption spectral changes that were enhanced by the MIR-FEL irradiation, and the potential use of MIR-FELs for the structural evaluation of biomaterials is suggested.
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Affiliation(s)
- Takayasu Kawasaki
- IR Free Electron Laser Research Center, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Heishun Zen
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kento Ozaki
- Photon Production Laboratory Ltd, 576-1 Anamura-cho, Kusatsu, Shiga 525-0012, Japan
| | - Hironari Yamada
- Photon Production Laboratory Ltd, 576-1 Anamura-cho, Kusatsu, Shiga 525-0012, Japan
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Medical Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Medical Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
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4
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Ajito K, Ueno Y, Kim JY, Sumikama T. Capturing the Freeze-Drying Dynamics of NaCl Nanoparticles Using THz Spectroscopy. J Am Chem Soc 2018; 140:13793-13797. [PMID: 30351129 DOI: 10.1021/jacs.8b07828] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sodium chloride (NaCl) aqueous solution becomes NaCl hydrate, NaCl·2H2O, at low temperature, which is different from potassium chloride and is a typical complex model for studying the freeze-drying process in foods and pharmaceuticals. Here, we detected unit-cell-sized NaCl particles in ice as precursor substances of NaCl·2H2O during freezing of NaCl solution by using terahertz (THz) spectroscopy. In the freezing process, Na+ and Cl- ions form two types of metastable unit-cell-sized NaCl particles on the pathway to the well-known NaCl·2H2O crystal production, which are not listed in the phase diagram of freezing of NaCl solution but have absorption peaks in THz spectra. This finding of single unit-cell-sized particles signifies the importance of studying the freeze-drying process in-depth and offers a new possibility for the development of freeze-drying technology for the manufacture of nanometer-sized particles such as ultrafine pharmaceutical powders, which more readily dissolve in water.
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Affiliation(s)
- Katsuhiro Ajito
- NTT Device Technology Laboratories , NTT Corporation , Atsugi 243-0198 , Japan
| | - Yuko Ueno
- NTT Basic Research Laboratories , NTT Corporation , Atsugi 243-0198 , Japan
| | - Jae-Young Kim
- NTT Device Technology Laboratories , NTT Corporation , Atsugi 243-0198 , Japan
| | - Takashi Sumikama
- Institute for Molecular Science , Myodaiji, Okazaki 444-8585 , Japan
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Kalanoor B, Ronen M, Oren Z, Gerber D, Tischler YR. New Method to Study the Vibrational Modes of Biomolecules in the Terahertz Range Based on a Single-Stage Raman Spectrometer. ACS OMEGA 2017; 2:1232-1240. [PMID: 28393138 PMCID: PMC5377281 DOI: 10.1021/acsomega.6b00547] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 03/14/2017] [Indexed: 05/04/2023]
Abstract
The low-frequency vibrational (LFV) modes of biomolecules reflect specific intramolecular and intermolecular thermally induced fluctuations that are driven by external perturbations, such as ligand binding, protein interaction, electron transfer, and enzymatic activity. Large efforts have been invested over the years to develop methods to access the LFV modes due to their importance in the studies of the mechanisms and biological functions of biomolecules. Here, we present a method to measure the LFV modes of biomolecules based on Raman spectroscopy that combines volume holographic filters with a single-stage spectrometer, to obtain high signal-to-noise-ratio spectra in short acquisition times. We show that this method enables LFV mode characterization of biomolecules even in a hydrated environment. The measured spectra exhibit distinct features originating from intra- and/or intermolecular collective motion and lattice modes. The observed modes are highly sensitive to the overall structure, size, long-range order, and configuration of the molecules, as well as to their environment. Thus, the LFV Raman spectrum acts as a fingerprint of the molecular structure and conformational state of a biomolecule. The comprehensive method we present here is widely applicable, thus enabling high-throughput study of LFV modes of biomolecules.
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Affiliation(s)
- Basanth
S. Kalanoor
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Bar-Ilan Institute for Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Maria Ronen
- Mina and Everard Goodman Faculty
of Life Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel
- Bar-Ilan Institute for Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Ziv Oren
- Mina and Everard Goodman Faculty
of Life Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel
- Department
of Biotechnology, Israel Institute of Biological
Research, Nes-Ziona 7410001, Israel
| | - Doron Gerber
- Mina and Everard Goodman Faculty
of Life Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel
- Bar-Ilan Institute for Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
- E-mail: (D.G.)
| | - Yaakov R. Tischler
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Bar-Ilan Institute for Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
- E-mail: (Y.R.T.)
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6
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Png GM, Fischer BM, Appadoo D, Plathe R, Abbott D. Double-layered nitrocellulose membrane sample holding technique for THz and FIR spectroscopic measurements. OPTICS EXPRESS 2015; 23:4997-5013. [PMID: 25836535 DOI: 10.1364/oe.23.004997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In terahertz (THz) and far-infrared (FIR) spectroscopic measurements, weak absorption spectral features due to small quantities of test sample can be masked by undesirable etalon fringe artifacts caused by multiple reflections within a pellet or a rigid sample holder. A double-layered nitrocellulose (NC) membrane structure is proposed in this paper as an alternative holder for small quantities of either dry or wet pure (no added polyethylene powder) samples with significantly reduced etalon artifacts. Utilizing a THz time-domain spectroscopy system and a synchrotron source, we demonstrate the performance of the NC structure across the THz/FIR spectrum, benchmarking against pellets holding similarly small quantities of α-lactose powder either with or without different grades of polyethylene powder. With only pure samples to consider, scattering can be mitigated effectively in NC-derived spectra to reduce their baselines.
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7
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Bye JW, Meliga S, Ferachou D, Cinque G, Zeitler JA, Falconer RJ. Analysis of the Hydration Water around Bovine Serum Albumin Using Terahertz Coherent Synchrotron Radiation. J Phys Chem A 2013; 118:83-8. [DOI: 10.1021/jp407410g] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jordan W. Bye
- Department of Chemical & Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield S1 3JD, England
| | - Stefano Meliga
- Australian Institute
for Bioengineering and Nanotechnology, University of Queensland, St Lucia, Queensland 4072, Australia
| | - Denis Ferachou
- Department of Chemical Engineering & Biotechnology, University of Cambridge, Cambridge CB2 3RA, England
| | | | - J. Axel Zeitler
- Department of Chemical Engineering & Biotechnology, University of Cambridge, Cambridge CB2 3RA, England
| | - Robert J. Falconer
- Department of Chemical & Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield S1 3JD, England
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8
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Xie LH, Dai H, Jin BB, Han Y, Tai Q, Yi MD, Yang T, Wu PH, Huang W. Characterization of Hindered Amine Light Stabilizers in Polymer Matrix Using Terahertz Time-Domain Spectroscopy. MACROMOL CHEM PHYS 2012. [DOI: 10.1002/macp.201100657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Luong TQ, Verma PK, Mitra RK, Havenith M. Do hydration dynamics follow the structural perturbation during thermal denaturation of a protein: a terahertz absorption study. Biophys J 2011; 101:925-33. [PMID: 21843484 DOI: 10.1016/j.bpj.2011.05.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 03/26/2011] [Accepted: 05/03/2011] [Indexed: 01/28/2023] Open
Abstract
We investigate the thermal denaturation of human serum albumin and the associated solvation using terahertz (THz) spectroscopy in aqueous buffer solution. Far- and near-ultraviolet circular dichroism spectroscopy reveal that the protein undergoes a native (N) to extended (E) state transition at temperature ≤55°C with a marginal change in the secondary and tertiary structure. At 70°C, the protein transforms into an unfolded (U) state with significant irreversible disruption of its structures. We measure the concentration- and temperature-dependent THz absorption coefficient (α) of the protein solution using a p-Ge THz difference spectrometer (2.1-2.8 THz frequency range), thereby probing the collective protein-water network dynamics. When the solvated protein is heated up to 55°C and cooled down again, a reversible change in THz absorption is observed. When increasing the temperature up to 70°C, we find a dramatic irreversible change of THz absorption. The increase in THz absorption compared to bulk water is attributed to a blue shift in the spectrum of the solvated protein compared to bulk water. This is supported by measurements of THz absorption coefficients using THz time-domain spectroscopy (0.1-1.2 THz frequency range). We also use picosecond-resolved fluorescence spectroscopy of the tryptophan 214 moiety of human serum albumin. All experimental observations can be explained by a change in the hydration dynamics of the solvated protein due to the additional exposure of hydrophobic residues upon unfolding.
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Affiliation(s)
- Trung Quan Luong
- Department of Physical Chemistry II, Ruhr-University Bochum, Bochum, Germany
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11
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Ding T, Huber T, Middelberg AP, Falconer RJ. Characterization of Low-Frequency Modes in Aqueous Peptides Using Far-Infrared Spectroscopy and Molecular Dynamics Simulation. J Phys Chem A 2011; 115:11559-65. [DOI: 10.1021/jp200553d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tao Ding
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, Australia
| | - Anton P.J. Middelberg
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
| | - Robert J. Falconer
- Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield S1 3JD, England
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12
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Png GM, Fumeaux C, Stringer MR, Miles RE, Abbott D. Terahertz scattering by subwavelength cylindrical arrays. OPTICS EXPRESS 2011; 19:10138-10152. [PMID: 21643272 DOI: 10.1364/oe.19.010138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate the use of a full-wave electromagnetic field simulator to verify terahertz (THz) transmission-mode spectroscopic measurements of periodic arrays containing subwavelength cylindrical scatterers. Many existing THz scattering studies utilize analytical solutions, which were developed for a single scatterer. For multiple scatterers, a scaling factor equal to the number of scatterers is applied, accounting for interference between far-field radiative contributions from those scatterers but not their near-field mutual coupling. Consequently, analytical solutions do not accurately verify measurements. Conversely, results from the full-wave electromagnetic field simulator elucidate our measurements well, and provide an important insight into how the scattering behavior of cylindrical scatterers is influenced by test conditions.
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Affiliation(s)
- Gretel M Png
- School of Electrical and Electronic Engineering, University of Adelaide, SA 5005, Australia.
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13
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Sun Y, Zhang Y, Pickwell-Macpherson E. Investigating antibody interactions with a polar liquid using terahertz pulsed spectroscopy. Biophys J 2011; 100:225-31. [PMID: 21190675 DOI: 10.1016/j.bpj.2010.11.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 11/10/2010] [Accepted: 11/16/2010] [Indexed: 01/17/2023] Open
Abstract
In this article, we use terahertz spectroscopy to study the dielectric properties of the peroxidase-conjugated affinity purified goat anti-cat immunoglobulin G and the fluorescein-conjugated affinity purified goat anti-cat immunoglobulin G when they interact with polar liquids. The influence of protein concentration, as well as presence of glycerol as a cosolvent, is determined by estimation of the effective hydration shell radius of the protein in solution. The dielectric spectra in this study are measured over the frequency range 0.1-1.3 THz and it is found that the dielectric properties are dependent on the type of the charges in the hydrogen-bonded antibodies' networks. Our results indicate that the terahertz dielectric properties of polar liquids are strongly affected by the presence of the antibody and suggest that the dielectric spectrum is particularly powerful in the study of structural and conformational properties of proteins. Therefore, terahertz spectroscopy is a very sensitive approach to investigate structural features of biological systems.
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Affiliation(s)
- Yiwen Sun
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong
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14
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Zakaria HA, Fischer BM, Bradley AP, Jones I, Abbott D, Middelberg APJ, Falconer RJ. Low-frequency spectroscopic analysis of monomeric and fibrillar lysozyme. APPLIED SPECTROSCOPY 2011; 65:260-4. [PMID: 21352645 DOI: 10.1366/10-06162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Terahertz time-domain spectroscopy (THz-TDS) and Fourier transform infrared (FT-IR) spectroscopy were used to generate far-infrared and low-frequency spectral measurements of monomeric lysozyme and lysozyme fibrils. The formation of lysozyme fibrils was verified by the Thioflavin T assay and transmission electron microscopy (TEM). It was evident in the FT-IR spectra that between 150 and 350 cm(-1) the two spectra diverge, with the lysozyme fibrils showing higher absorbance intensity than the monomeric form. The broad absorption phenomenon is likely due to light scattered from the fibrillar architecture of lysozyme fibrils as supported by simulation of Rayleigh light scattering. The lack of discrete phonon-like peaks suggest that far-infrared spectroscopy cannot detect vibrational modes between the highly ordered hydrogen-bonded beta-pleated sheets of the lysozyme subunit.
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Affiliation(s)
- Hidayatul A Zakaria
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
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15
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Ding T, Li R, Zeitler JA, Huber TL, Gladden LF, Middelberg APJ, Falconer RJ. Terahertz and far infrared spectroscopy of alanine-rich peptides having variable ellipticity. OPTICS EXPRESS 2010; 18:27431-44. [PMID: 21197019 DOI: 10.1364/oe.18.027431] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Terahertz spectra of four alanine-rich peptides with known secondary structures were studied by terahertz time domain spectroscopy (THz-TDS) and by Fourier transform infrared spectroscopy (FTIR) using a synchrotron light source and a liquid-helium cooled bolometer. At ambient temperatures the usable bandwidth was restricted to 0.2-1.5 THz by the absorbance of water. The existence of a solvation shell around the peptide in solution was observed and its size estimated to be between 11 and 17 Å. By cooling the peptide solution to 80 K in order to reduce the water absorbance the bandwidth was increased to 0.1-3.0 THz for both THz-TDS and FTIR. Spectra were consistent with monotonic absorbance of the peptide and the existence of a solid amorphous low density solvation shell.
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Affiliation(s)
- Tao Ding
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
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Falconer RJ, Zakaria HA, Fan YY, Bradley AP, Middelberg APJ. Far-infrared spectroscopy of protein higher-order structures. APPLIED SPECTROSCOPY 2010; 64:1259-64. [PMID: 21073795 DOI: 10.1366/000370210793335025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Far-infrared (FIR) spectroscopy in the spectral region of 50-450 cm(-1) was used to study a series of protein higher-order structures constructed using β-lactoglobulin and polyomavirus capsid protein VP1. There were marked differences in the spectra for β-lactoglobulin monomer and dimer and between untreated β-lactoglobulin and heat-induced gels formed at neutral pH. Untreated β-lactoglobulin and heat-induced gels formed at acidic pH exhibited little difference in their spectra. Assembly of the quaternary structure of polyomavirus virus-like particles also caused large changes in the FIR spectra. These findings suggest that FIR spectroscopy may prove useful in studying some protein quaternary and higher-order structures. There was evidence of detection of β-lactoglobulin dimerization, intermolecular disulfide bonding in heat-induced neutral gels, and polyomavirus virus-like particle assembly but no evidence that FIR could detect β-lactoglobulin fibrils with their polymeric structure and hydrogen-bonded intermolecular β-pleated sheeting.
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Affiliation(s)
- Robert J Falconer
- The University of Queensland, NCRIS Biotechnology Products, Australian Institute for Bioengineering and Nanotechnology, Brisbane QLD 4072, Australia.
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