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Poonprasartporn A, Xiao J, Chan KLA. A study of WZB117 as a competitive inhibitor of glucose transporter in high glucose treated PANC-1 cells by live-cell FTIR spectroscopy. Talanta 2024; 266:125031. [PMID: 37549570 DOI: 10.1016/j.talanta.2023.125031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 08/09/2023]
Affiliation(s)
- Anchisa Poonprasartporn
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences, King's College London, SE1 9NH, United Kingdom.
| | - Jin Xiao
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences, King's College London, SE1 9NH, United Kingdom
| | - K L Andrew Chan
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences, King's College London, SE1 9NH, United Kingdom.
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2
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Zhang W, Metzger H, Vlatakis S, Claxton A, Carbajal MA, Fung LF, Mason J, Chan KLA, Pouliopoulos AN, Fleck RA, Prentice P, Thanou M. Characterising the chemical and physical properties of phase-change nanodroplets. Ultrason Sonochem 2023; 97:106445. [PMID: 37257208 PMCID: PMC10241977 DOI: 10.1016/j.ultsonch.2023.106445] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/04/2023] [Accepted: 05/15/2023] [Indexed: 06/02/2023]
Abstract
Phase-change nanodroplets have attracted increasing interest in recent years as ultrasound theranostic nanoparticles. They are smaller compared to microbubbles and they may distribute better in tissues (e.g. in tumours). They are composed of a stabilising shell and a perfluorocarbon core. Nanodroplets can vaporise into echogenic microbubbles forming cavitation nuclei when exposed to ultrasound. Their perfluorocarbon core phase-change is responsible for the acoustic droplet vaporisation. However, methods to quantify the perfluorocarbon core in nanodroplets are lacking. This is an important feature that can help explain nanodroplet phase change characteristics. In this study, we fabricated nanodroplets using lipids shell and perfluorocarbons. To assess the amount of perfluorocarbon in the core we used two methods, 19F NMR and FTIR. To assess the cavitation after vaporisation we used an ultrasound transducer (1.1 MHz) and a high-speed camera. The 19F NMR based method showed that the fluorine signal correlated accurately with the perfluorocarbon concentration. Using this correlation, we were able to quantify the perfluorocarbon core of nanodroplets. This method was used to assess the content of the perfluorocarbon of the nanodroplets in solutions over time. It was found that perfluoropentane nanodroplets lost their content faster and at higher ratio compared to perfluorohexane nanodroplets. The high-speed imaging indicates that the nanodroplets generate cavitation comparable to that from commercial contrast agent microbubbles. Nanodroplet characterisation should include perfluorocarbon concentration assessment as critical information for their development.
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Affiliation(s)
- Weiqi Zhang
- Institute of Cancer & Pharmaceutical Sciences, King's College London, United Kingdom
| | - Hilde Metzger
- School of Engineering, University of Glasgow, United Kingdom
| | - Stavros Vlatakis
- Institute of Cancer & Pharmaceutical Sciences, King's College London, United Kingdom
| | - Amelia Claxton
- Institute of Cancer & Pharmaceutical Sciences, King's College London, United Kingdom
| | | | - Leong Fan Fung
- Department of Surgical & Interventional Engineering, King's College London, United Kingdom
| | - James Mason
- Institute of Cancer & Pharmaceutical Sciences, King's College London, United Kingdom
| | - K L Andrew Chan
- Institute of Cancer & Pharmaceutical Sciences, King's College London, United Kingdom
| | | | - Roland A Fleck
- Centre for Ultrastructural Imaging, King's College London, United Kingdom
| | - Paul Prentice
- School of Engineering, University of Glasgow, United Kingdom
| | - Maya Thanou
- Institute of Cancer & Pharmaceutical Sciences, King's College London, United Kingdom.
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3
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Terakosolphan W, Altharawi A, Poonprasartporn A, Harvey RD, Forbes B, Chan KLA. In vitro Fourier transform infrared spectroscopic study of the effect of glycerol on the uptake of beclomethasone dipropionate in living respiratory cells. Int J Pharm 2021; 609:121118. [PMID: 34560211 DOI: 10.1016/j.ijpharm.2021.121118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 12/01/2022]
Abstract
The quantification of drug in living cells is of increasing interest in pharmaceutical research because of its importance in understanding drug efficacy and toxicity. Label-free in situ measurement methods are advantageous for their ability to obtain chemical and time profiles without the need of labelling or extraction steps. We have previously shown that Fourier transform infrared (FTIR) spectroscopy has the potential to quantify drug in situ within living cells at micromolar level when a simple solution of drug was added to the medium. The purpose of this study was to demonstrate that the approach can evaluate more complex systems such as the effect of membrane modification by a formulation on drug uptakes. The inhaled corticosteroid, beclomethasone dipropionate (BDP), in Calu-3 respiratory epithelial cells in the absence and presence of glycerol, an excipient in some inhaled medicines was used as the model system. The FTIR method was first validated for limit of detection (LOD) and quantification (LOQ) according to published guidelines and the LOQ was found to be ∼ 20 μM, good enough to quantify BDP in the living cell. The uptake of BDP by living Calu-3 cells was found to be reduced in the presence of glycerol as expected due to the stiffening of the cell membrane by the presence of glycerol in the formulation. This study demonstrates the valuable analytical capability of live-cell FTIR to study the effect of formulation on drug transport in lungs and to evaluate drug availability to intracellular targets. We conclude that FTIR has potential to contribute widely at the frontier of live-cell studies.
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Affiliation(s)
- Wachirun Terakosolphan
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
| | - Ali Altharawi
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom; Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | | | - Richard D Harvey
- Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Althanstraße 14 (UZA II), 1090 Wien, Austria
| | - Ben Forbes
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
| | - K L Andrew Chan
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom.
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4
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Poonprasartporn A, Chan KLA. Live-cell ATR-FTIR spectroscopy as a novel bioanalytical tool for cell glucose metabolism research. Biochim Biophys Acta Mol Cell Res 2021; 1868:119024. [PMID: 33831457 DOI: 10.1016/j.bbamcr.2021.119024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/19/2021] [Accepted: 03/26/2021] [Indexed: 12/17/2022]
Abstract
Current novel drug developments for the treatment of diabetes require multiple bioanalytical assays to interrogate the cellular metabolism, which are costly, laborious and time-consuming. Fourier-transform infrared (FTIR) spectroscopy is a nondestructive, label-free, sensitive and low-cost technique that is recently found to be suitable for studying living cells. The aim of this study is to demonstrate that live-cell FTIR can be applied to study the differences in glucose metabolism in cells in normal culturing medium and cells treated in high glucose (a diabetes model) in order to highlight the potential of the technique in diabetes research. Live HepG2 cells were treated in normal glucose (3.8 mM; control) or high glucose (25 mM) medium and were measured directly using the FTIR approach. Principal component analysis was used to highlight any possible correlated changes 24, 48 and 72 h after treatments. FTIR spectra of live cell treated in normal and high glucose medium have shown significant differences (p < 0.05) for all treatment time. The control cells have seen an increased in the absorbance at 1088, 1240 and 1400 cm-1, which are associated with phosphate stretching mode vibrations from phosphorylated proteins and DNA back bone; and symmetric stretching mode vibration of COO- from fatty acids, amino acids, lipids and carbohydrate metabolites. However, the high glucose treated cells have shown a different changes in the 1000-1200 cm-1 region, which is linked to the glycogen and ATP:ADP ratio. In conclusion, live-cell FTIR can be a low-cost method for the studies of metabolic changes in cells.
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Affiliation(s)
- Anchisa Poonprasartporn
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences, King's College London, SE1 9NH, United Kingdom
| | - K L Andrew Chan
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences, King's College London, SE1 9NH, United Kingdom.
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5
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Wright SL, Ulke J, Font A, Chan KLA, Kelly FJ. Atmospheric microplastic deposition in an urban environment and an evaluation of transport. Environ Int 2020; 136:105411. [PMID: 31889555 PMCID: PMC7013824 DOI: 10.1016/j.envint.2019.105411] [Citation(s) in RCA: 340] [Impact Index Per Article: 85.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/15/2019] [Accepted: 12/10/2019] [Indexed: 05/19/2023]
Abstract
Microplastics are a global environmental issue contaminating aquatic and terrestrial environments. They have been reported in atmospheric deposition, and indoor and outdoor air, raising concern for public health due to the potential for exposure. Moreover, the atmosphere presents a new vehicle for microplastics to enter the wider environment, yet our knowledge of the quantities, characteristics and pathways of airborne microplastics is sparse. Here we show microplastics in atmospheric deposition in a major population centre, central London. Microplastics were found in all samples, with deposition rates ranging from 575 to 1008 microplastics/m2/d. They were found in various shapes, of which fibrous microplastics accounted for the great majority (92%). Across all samples, 15 different petrochemical-based polymers were identified. Bivariate polar plots indicated dependency on wind, with different source areas for fibrous and non-fibrous airborne microplastics. This is the first evidence of airborne microplastics in London and confirms the need to include airborne pathways when consolidating microplastic impacts on the wider environment and human health.
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Affiliation(s)
- S L Wright
- MRC Centre for Environment and Health, Analytical, Environmental and Forensic Sciences, King's College London, London, United Kingdom; Environmental Research Group, Analytical, Environmental and Forensic Sciences, King's College London, London, United Kingdom.
| | - J Ulke
- MRC Centre for Environment and Health, Analytical, Environmental and Forensic Sciences, King's College London, London, United Kingdom
| | - A Font
- MRC Centre for Environment and Health, Analytical, Environmental and Forensic Sciences, King's College London, London, United Kingdom; Environmental Research Group, Analytical, Environmental and Forensic Sciences, King's College London, London, United Kingdom
| | - K L A Chan
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences, King's College London, London, United Kingdom
| | - F J Kelly
- MRC Centre for Environment and Health, Analytical, Environmental and Forensic Sciences, King's College London, London, United Kingdom; Environmental Research Group, Analytical, Environmental and Forensic Sciences, King's College London, London, United Kingdom
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6
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Phelan J, Altharawi A, Chan KLA. Tracking glycosylation in live cells using FTIR spectroscopy. Talanta 2020; 211:120737. [PMID: 32070609 DOI: 10.1016/j.talanta.2020.120737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/09/2020] [Accepted: 01/11/2020] [Indexed: 12/13/2022]
Abstract
This is the first demonstration of the study of glycan protein turnover in living cells by FTIR with commercially available tetraacetylated N-Azidoacetyl-D-Mannosamine (Ac4ManNAz) label. The FTIR analysis has shown to be able to monitor the metabolism of glycans in living cells in real time. The method is simple, quantitative and requires equipment that are available in many laboratories. It can be used in a wide range of applications such as the study of glycosylation and cell-signalling.
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Affiliation(s)
- Joshua Phelan
- Institute of Pharmaceutical Science, King's College London, SE1 9NH, UK; Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, USA
| | - Ali Altharawi
- Institute of Pharmaceutical Science, King's College London, SE1 9NH, UK
| | - K L Andrew Chan
- Institute of Pharmaceutical Science, King's College London, SE1 9NH, UK.
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7
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Abstract
Fourier transform infrared spectroscopy (FTIR) has been shown to be a promising tool for identifying the mode of action of drugs.
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Affiliation(s)
- Ali Altharawi
- School of Cancer and Pharmaceutical Science
- King's College London
- UK
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8
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Chan KLA, Fale PLV, Atharawi A, Wehbe K, Cinque G. Subcellular mapping of living cells via synchrotron microFTIR and ZnS hemispheres. Anal Bioanal Chem 2018; 410:6477-6487. [PMID: 30032447 PMCID: PMC6132686 DOI: 10.1007/s00216-018-1245-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/25/2018] [Accepted: 07/04/2018] [Indexed: 11/13/2022]
Abstract
FTIR imaging is a label-free, non-destructive method valuably exploited in the study of the biological process in living cells. However, the long wavelength/low spatial resolution and the strong absorbance of water are still key constrains in the application of IR microscopy ex vivo. In this work, a new retrofit approach based on the use of ZnS hemispheres is introduced to significantly improve the spatial resolution on live cell FTIR imaging. By means of two high refractive index domes sandwiching the sample, a lateral resolution close to 2.2 μm at 6 μm wavelength has been achieved, i.e. below the theoretical diffraction limit in air and more than twice the improvement (to ~λ/2.7) from our previous attempt using CaF2 lenses. The ZnS domes also allowed an extended spectral range to 950 cm−1, in contrast to the cut-off at 1050 cm−1 using CaF2. In combination with synchrotron radiation source, microFTIR provides an improved signal-to-noise ratio through the circa 12 μm thin layer of medium, thus allowing detailed distribution of lipids, protein and nucleic acid in the surround of the nucleus of single living cells. Endoplasmic reticula were clearly shown based on the lipid ν(CH) and ν(C=O) bands, while the DNA was imaged based on the ν(PO2−) band highlighting the nucleus region. This work has also included a demonstration of drug (doxorubicin) in cell measurement to highlight the potential of this approach. Graphical abstract ![]()
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Affiliation(s)
- K L Andrew Chan
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Science, King's College London, London, SE1 9NH, UK.
| | - Pedro L V Fale
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Science, King's College London, London, SE1 9NH, UK.,Center of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Ali Atharawi
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Science, King's College London, London, SE1 9NH, UK
| | - Katia Wehbe
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Gianfelice Cinque
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
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Abstract
FTIR spectroscopic imaging is a label-free, non-destructive and chemically specific technique that can be utilised to study a wide range of biomedical applications such as imaging of biopsy tissues, fixed cells and live cells, including cancer cells. In particular, the use of FTIR imaging in attenuated total reflection (ATR) mode has attracted much attention because of the small, but well controlled, depth of penetration and corresponding path length of infrared light into the sample. This has enabled the study of samples containing large amounts of water, as well as achieving an increased spatial resolution provided by the high refractive index of the micro-ATR element. This review is focused on discussing the recent developments in FTIR spectroscopic imaging, particularly in ATR sampling mode, and its applications in the biomedical science field as well as discussing the future opportunities possible as the imaging technology continues to advance.
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Affiliation(s)
- K L Andrew Chan
- Institute of Pharmaceutical Science, King's College London, SE1 9NH, UK
| | - Sergei G Kazarian
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
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10
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Fale PL, Altharawi A, Chan KLA. In situ Fourier transform infrared analysis of live cells' response to doxorubicin. Biochim Biophys Acta 2015; 1853:2640-8. [PMID: 26231933 DOI: 10.1016/j.bbamcr.2015.07.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/08/2015] [Accepted: 07/26/2015] [Indexed: 11/15/2022]
Abstract
The study of the response of cancer cells to chemotherapy drugs is of high importance due to the specificity of some drugs to certain types of cancer and the resistance of some specific cancer types to chemotherapy drugs. Our aim was to develop and apply the label-free and non-destructive Fourier transform infrared (FTIR) method to determine the sensitivity of three different cancer cell-lines to a common anti-cancer drug doxorubicin at different concentrations and to demonstrate that information about the mechanism of resistance to the chemotherapy drug can be extracted from spectral data. HeLa, PC3, and Caco-2 cells were seeded and grown on an attenuated total reflection (ATR) crystal, doxorubicin was applied at the clinically significant concentration of 0.1-20 μM, and spectra of the cells were collected hourly over 20 h. Analysis of the amide bands was correlated with cell viability, which had been cross validated with MTT assays, allowing to determine that the three cell lines had significantly different resistance to doxorubicin. The difference spectra and principal component analysis (PCA) highlighted the subtle chemical changes in the living cells under treatment. Spectral regions assigned to nucleic acids (mainly 1085 cm(-1)) and carbohydrates (mainly 1024 cm(-1)) showed changes that could be related to the mode of action of the drug and the mechanism of resistance of the cell lines to doxorubicin. This is a cost-effective method that does not require bioassay reagents but allows label-free, non-destructive and in situ analysis of chemical changes in live cells, using standard FTIR equipment adapted to ATR measurements.
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Affiliation(s)
- Pedro L Fale
- Institute of Pharmaceutical Science, King's College London, SE1 9NH, UK
| | - Ali Altharawi
- Institute of Pharmaceutical Science, King's College London, SE1 9NH, UK
| | - K L Andrew Chan
- Institute of Pharmaceutical Science, King's College London, SE1 9NH, UK.
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Chan KLA, Fale PLV. Label-Free in Situ Quantification of Drug in Living Cells at Micromolar Levels Using Infrared Spectroscopy. Anal Chem 2014; 86:11673-9. [DOI: 10.1021/ac503915c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- K. L. Andrew Chan
- Institute
of Pharmaceutical
Science, King's College London, London SE1 9NH, U.K
| | - Pedro L. V. Fale
- Institute
of Pharmaceutical
Science, King's College London, London SE1 9NH, U.K
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12
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Abstract
The label-free, non-destructive chemical analysis offered by FTIR spectroscopic imaging is a very attractive and potentially powerful tool for studies of live biological cells. FTIR imaging of live cells is a challenging task, due to the fact that cells are cultured in an aqueous environment. While the synchrotron facility has proven to be a valuable tool for FTIR microspectroscopic studies of single live cells, we have demonstrated that high quality infrared spectra of single live cells using an ordinary Globar source can also be obtained by adding a pair of lenses to a common transmission liquid cell. The lenses, when placed on the transmission cell window, form pseudo hemispheres which removes the refraction of light and hence improve the imaging and spectral quality of the obtained data. This study demonstrates that infrared spectra of single live cells can be obtained without the focus shifting effect at different wavenumbers, caused by the chromatic aberration. Spectra of the single cells have confirmed that the measured spectral region remains in focus across the whole range, while spectra of the single cells measured without the lenses have shown some erroneous features as a result of the shift of focus. It has also been demonstrated that the addition of lenses can be applied to the imaging of cells in microfabricated devices. We have shown that it was not possible to obtain a focused image of an isolated cell in a droplet of DPBS in oil unless the lenses are applied. The use of the approach described herein allows for well focused images of single cells in DPBS droplets to be obtained.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, SW7 2AZ, London, UK
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Chan KLA, Kazarian SG. Correcting the Effect of Refraction and Dispersion of Light in FT-IR Spectroscopic Imaging in Transmission through Thick Infrared Windows. Anal Chem 2012; 85:1029-36. [DOI: 10.1021/ac302846d] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. L. Andrew Chan
- Department of Chemical
Engineering, Imperial College London, SW7 2AZ, United Kingdom
| | - Sergei G. Kazarian
- Department of Chemical
Engineering, Imperial College London, SW7 2AZ, United Kingdom
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Abstract
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Rapid, in situ, and label-free chemical analysis in microfluidic
devices is highly desirable. FT-IR spectroscopic imaging has previously
been shown to be a powerful tool to visualize the distribution of
different chemicals in flows in a microfluidic device at near video
rate imaging speed without tracers or dyes. This paper demonstrates
the possibility of using this imaging technology to capture the chemical
information of all reactants and products at different points in time
and space in a two-phase system. Differences in the rates of chemical
reactions in laminar flow and segmented flow systems are also compared.
Neutralization of benzoic acid in decanol with disodium phosphate
in water has been used as the model reaction. Quantitative information,
such as concentration profiles of reactant and products, can be extracted
from the imaging data. The same feed flow rate was used in both the
laminar flow and segmented flow systems. The laminar flow pattern
was achieved using a plain wide T-junction, whereas the segmented
flow was achieved by introducing a narrowed section and a nozzle at
the T-junction. The results show that the reaction rate is limited
by diffusion and is much slower with the laminar flow pattern, whereas
the reaction is completed more quickly in the segmented flow due to
better mixing.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, UK
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16
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Glassford S, Chan KLA, Byrne B, Kazarian SG. Chemical imaging of protein adsorption and crystallization on a wettability gradient surface. Langmuir 2012; 28:3174-3179. [PMID: 22260648 DOI: 10.1021/la204524w] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The use of self-assembled monolayers is an established method to study the effect of surface properties on proteins and other biological materials. The generation of a monolayer with a gradient of chemical properties allows for the study of multiple surface properties simultaneously in a high throughput manner. Typically, in order to detect the presence of proteins or biological material on a surface, the use of additional dyes or tags is required. Here we present a novel method of studying the effect of gradient surface properties on protein adsorption and crystallization in situ through the use of ATR-FTIR spectroscopic imaging, which removes the need for additional labeling. We describe the successful application of this technique to the measurement of the growth of a gradient monolayer of octyltrichlorosilane across the surface of a silicon ATR element. ATR-FTIR imaging was also used to study the adsorption of lysozyme, as a model protein, onto the modified surface. The sensitivity of measurements obtained with a focal plane array (FPA) detector were improved though the use of pixel averaging which allowed small absorption bands to be detected with minimal effect on the spatial resolution along the gradient. Study of the effect of surface hydrophobicity on both adsorption of lysozyme to the element and lysozyme crystallization revealed that more lysozyme adsorbed to the hydrophobic side of the ATR element and more lysozyme crystals formed in the same region. These findings strongly suggest a correlation exists between surface protein adsorption and protein crystallization. This method could be applied to the study of other proteins and whole cells.
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Affiliation(s)
- Stefanie Glassford
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
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Qian H, Kalinka G, Chan KLA, Kazarian SG, Greenhalgh ES, Bismarck A, Shaffer MSP. Mapping local microstructure and mechanical performance around carbon nanotube grafted silica fibres: methodologies for hierarchical composites. Nanoscale 2011; 3:4759-4767. [PMID: 21979874 DOI: 10.1039/c1nr10497g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The introduction of carbon nanotubes (CNTs) modifies bulk polymer properties, depending on intrinsic quality, dispersion, alignment, interfacial chemistry and mechanical properties of the nanofiller. These effects can be exploited to enhance the matrices of conventional microscale fibre-reinforced polymer composites, by using primary reinforcing fibres grafted with CNTs. This paper presents a methodology that combines atomic force microscopy, polarised Raman spectroscopy, and nanoindentation techniques, to study the distribution, alignment and orientation of CNTs in the vicinity of epoxy-embedded micrometre-scale silica fibres, as well as, the resulting local mechanical properties of the matrix. Raman maps of key features in the CNT spectra clearly show the CNT distribution and orientation, including a 'parted' morphology associated with long grafted CNTs. The hardness and indentation modulus of the epoxy matrix were improved locally by 28% and 24%, respectively, due to the reinforcing effects of CNTs. Moreover, a slower stress relaxation was observed in the epoxy region containing CNTs, which may be due to restricted molecular mobility of the matrix. The proposed methodology is likely to be relevant to further studies of nanocomposites and hierarchical composites.
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Affiliation(s)
- Hui Qian
- The Composites Centre, Imperial College London, London, SW7 2AZ, UK
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18
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Abstract
Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, SW7 2AZ, UK
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19
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Affiliation(s)
- K. L. Andrew Chan
- Department of Chemical Engineering and ‡Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - X. Niu
- Department of Chemical Engineering and ‡Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - A. J. deMello
- Department of Chemical Engineering and ‡Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - S. G. Kazarian
- Department of Chemical Engineering and ‡Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
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Zhang Q, Andrew Chan KL, Zhang G, Gillece T, Senak L, Moore DJ, Mendelsohn R, Flach CR. Raman microspectroscopic and dynamic vapor sorption characterization of hydration in collagen and dermal tissue. Biopolymers 2011; 95:607-15. [DOI: 10.1002/bip.21618] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/23/2011] [Accepted: 02/23/2011] [Indexed: 11/08/2022]
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21
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Frosch T, Chan KLA, Wong HC, Cabral JT, Kazarian SG. Nondestructive three-dimensional analysis of layered polymer structures with chemical imaging. Langmuir 2010; 26:19027-19032. [PMID: 21090660 DOI: 10.1021/la103683h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Three-dimensional (3D) chemical information was obtained by means of a combination of two-dimensional attenuated total reflection Fourier transform infrared (ATR-FT-IR) imaging with a focal plane array detector and variable angle depth profiling. Since the penetration depth of the evanescent wave in ATR spectroscopy is not limited by diffraction, it was possible to resolve thin sandwiched polymer layers nondestructively within a stack of polymer layers. Chemical images were obtained from layers of different thickness of the laminate by moving a custom-made aperture to specific positions on the condenser lens of the ATR accessory. Sequences of absorption images detect the successive appearance of thin, buried layers of polybutylmethacrylate (d(PBMA) = 400 nm) and polycarbonate (d(TMPC) = 300 nm) in different depths of the stack of polymer layers. The depth resolution of variable-angle ATR-FT-IR imaging is sufficiently high to detect surface roughness at the interface between different polymer layers. Two different stacks of polymers with reordered sandwich-layers were imaged simultaneously, demonstrating the potential of variable angle ATR-FT-IR for 3D-imaging of a sample with xyz-heterogeneity, which can be a powerful analytical technique for materials science and biomedical research.
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Affiliation(s)
- Torsten Frosch
- Department of Chemical Engineering, Imperial College London, SW7 2AZ, United Kingdom
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22
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Chan KLA, Kazarian SG. Finding a needle in a chemical haystack: tip-enhanced Raman scattering for studying carbon nanotubes mixtures. Nanotechnology 2010; 21:445704. [PMID: 20935357 DOI: 10.1088/0957-4484/21/44/445704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Tip-enhanced Raman scattering (TERS) has emerged as a powerful analytical tool for measuring chemical images with nanometre spatial resolution. In this paper, the application of TERS to study differentiation of single-walled carbon nanotubes (SWCNTs) with 14 nm spatial resolution is demonstrated by the measurement of a mixture of two different types of SWCNTs as the model sample. The results demonstrate that TERS is a viable tool for the detection and localization of different SWCNTs and amorphous carbon in mixed SWCNTs based on the spectral differences in the radial breathing mode and the D bands.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, London, UK
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23
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Porto IM, Saiani RA, Chan KLA, Kazarian SG, Gerlach RF, Bachmann L. Organic and inorganic content of fluorotic rat incisors measured by FTIR spectroscopy. Spectrochim Acta A Mol Biomol Spectrosc 2010; 77:59-63. [PMID: 20547096 DOI: 10.1016/j.saa.2010.04.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 04/15/2010] [Accepted: 04/27/2010] [Indexed: 05/29/2023]
Abstract
Details on how fluoride interferes in enamel mineralization are still controversial. Therefore, this study aimed at analyzing the organic contents of fluorosis-affected teeth using Fourier Transformation Infrared spectroscopy. To this end, 10 male Wistar rats were divided into two groups: one received 45 ppm fluoride in distilled water for 60 days; the other received distilled water only. Then, the lower incisors were removed and prepared for analysis by two FTIR techniques namely, transmission and micro-ATR. For the first technique, the enamel was powdered, whereas in the second case one fluorotic incisor was cut longitudinally for micro-ATR. Using transmission and powdered samples, FTIR showed a higher C-H content in the fluorotic enamel compared with control enamel (p<0.05, n=4 in the flurotic, and n=5 in the control group). Results from the micro-ATR-FTIR spectroscopic analysis on one longitudinally cut incisor carried out at six points reveal a higher C-H bond content at the surface of the enamel, with values decreasing toward the dentine-enamel junction, and reaching the lowest values at the subsuperficial enamel. These results agree with the morphological data, which indicate that in the rat incisor the fluorotic lesion is superficial, rather than subsuperficial, as in the case of human enamel. The results also suggest that the increased C-H bond content may extend toward the more basal enamel (intraosseous), indicating that fluorotic enamel may intrinsically contain more protein. Finally, particularly when coupled to ATR, FTIR is a suitable tool to study the rat incisor enamel, which is a largely used model of normal and abnormal amelogenesis. Further studies along this line may definitely answer some questions regarding protein content in fluorotic enamel as well as their origin.
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Affiliation(s)
- Isabel Maria Porto
- Department of Morphology, Dental School of Piracicaba, University of Campinas, Piracicaba, Avenida Limeira, 901, 13414-903 Piracicaba, SP, Brazil.
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Chayen NE, Govada L, Chan KLA, Bill RM, Kazarian SG. Attenuated total reflection-FT-IR spectroscopic imaging of protein crystallization. Acta Crystallogr A 2010. [DOI: 10.1107/s0108767310093244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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25
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Chan KLA, Niu X, de Mello AJ, Kazarian SG. Rapid prototyping of microfluidic devices for integrating with FT-IR spectroscopic imaging. Lab Chip 2010; 10:2170-2174. [PMID: 20532270 DOI: 10.1039/c004246c] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A versatile approach for the rapid prototyping of microfluidic devices suitable for use with FT-IR spectroscopic imaging is introduced. Device manufacture is based on the direct printing of paraffin onto the surface of an infrared transparent substrate, followed by encapsulation. Key features of this approach are low running costs, rapid production times, simplicity of design modifications and suitability for integration with FT-IR spectroscopic measurements. In the current experiments, the minimum width of channel walls was found to be approximately 120 mum and approximately 200 when a 25 mum and 12 mum spacer is used, respectively. Water and poly(ethylene glycol) are used as model fluids in a laminar flow regime, and are imaged in both transmission and attenuated total reflection (ATR) modes. It is established that adoption of transmission mode measurements yields superior sensitivity whilst the ATR mode is more suitable for quantitative analysis using strong spectral absorption bands. Results indicate that devices manufactured using this approach are suitable for use with in situ FT-IR spectroscopic imaging.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, SW7 2AZ, United Kingdom
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26
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Kazarian SG, Chan KLA. Micro- and macro-attenuated total reflection Fourier transform infrared spectroscopic imaging. Plenary Lecture at the 5th International Conference on Advanced Vibrational Spectroscopy, 2009, Melbourne, Australia. Appl Spectrosc 2010; 64:135A-152A. [PMID: 20482963 DOI: 10.1366/000370210791211673] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fourier transform infrared (FT-IR) spectroscopic imaging has become a very powerful method in chemical analysis. In this review paper we describe a variety of opportunities for obtaining FT-IR images using the attenuated total reflection (ATR) approach and provide an overview of fundamental aspects, accessories, and applications in both micro- and macro-ATR imaging modes. The advantages and versatility of both ATR imaging modes are discussed and the spatial resolution of micro-ATR imaging is demonstrated. Micro-ATR imaging has opened up many new areas of study that were previously precluded by inadequate spatial resolution (polymer blends, pharmaceutical tablets, cross-sections of blood vessels or hair, surface of skin, single live cells, cancerous tissues). Recent applications of ATR imaging in polymer research, biomedical and forensic sciences, objects of cultural heritage, and other complex materials are outlined. The latest advances include obtaining spatially resolved chemical images from different depths within a sample, and surface-enhanced images for macro-ATR imaging have also been presented. Macro-ATR imaging is a valuable approach for high-throughput analysis of materials under controlled environments. Opportunities exist for chemical imaging of dynamic aqueous systems, such as dissolution, diffusion, microfluidics, or imaging of dynamic processes in live cells.
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Affiliation(s)
- Sergei G Kazarian
- Department of Chemical Engineering, Imperial College London, SW7 2AZ, London, England
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27
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Abstract
Elucidating the chemical composition of microfluidic flows is crucial in both understanding and optimising reactive processes within small-volume environments. Herein we report the implementation of a novel detection methodology based on Attenuated Total Reflection (ATR)-Fourier Transform Infra-Red (FTIR) spectroscopic imaging using an infrared focal plane array detector for microfluidic applications. The method is based on the combination of an inverted prism-shape ATR crystal with a poly(dimethylsiloxane)-based microfluidic mixing device. To demonstrate the efficacy of this approach, we report the direct measurement and imaging of the mixing of two liquids of different viscosities and the imaging and mixing of H2O and D2O with consecutive H/D isotope exchange. This chemically specific imaging approach allows direct analysis of fluid composition as a function of spatial position without the use of added labels or dyes, and can be used to study many processes in microfluidics ranging from reactions to separations.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
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28
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Abstract
Infrared (IR) spectroscopy has been successfully applied to study the permeation of substances through human skin in a high-throughput manner. The sample of skin was placed on the measuring surface of an attenuated total reflection (ATR) crystal and was divided into several areas. These areas were separated using a specially designed grid created on the surface of the skin and each area was subjected to a different combination of permeant and enhancer. ATR Fourier transform infrared (FT-IR) imaging was applied to measure the permeation of 12 liquid samples through a piece of skin smaller than 5 cm(2). This work demonstrated that, using the ATR-FT-IR imaging method, it is possible to measure and directly compare the transdermal processes of several permeants under identical conditions.
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Affiliation(s)
- Jean-Michel Andanson
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK
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29
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Chan KLA, Govada L, Bill RM, Chayen NE, Kazarian SG. Attenuated Total Reflection-FT-IR Spectroscopic Imaging of Protein Crystallization. Anal Chem 2009; 81:3769-75. [DOI: 10.1021/ac900455y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- K. L. Andrew Chan
- Department of Chemical Engineering, Faculty of Engineering and Department of Bio-Molecular Medicine, SORA Division, Faculty of Medicine, Imperial College London, SW7 2AZ, United Kingdom, and School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Lata Govada
- Department of Chemical Engineering, Faculty of Engineering and Department of Bio-Molecular Medicine, SORA Division, Faculty of Medicine, Imperial College London, SW7 2AZ, United Kingdom, and School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Roslyn M. Bill
- Department of Chemical Engineering, Faculty of Engineering and Department of Bio-Molecular Medicine, SORA Division, Faculty of Medicine, Imperial College London, SW7 2AZ, United Kingdom, and School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Naomi E. Chayen
- Department of Chemical Engineering, Faculty of Engineering and Department of Bio-Molecular Medicine, SORA Division, Faculty of Medicine, Imperial College London, SW7 2AZ, United Kingdom, and School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Sergei G. Kazarian
- Department of Chemical Engineering, Faculty of Engineering and Department of Bio-Molecular Medicine, SORA Division, Faculty of Medicine, Imperial College London, SW7 2AZ, United Kingdom, and School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom
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Andrew Chan KL, Zhang G, Tomic-Canic M, Stojadinovic O, Lee B, Flach CR, Mendelsohn R. A coordinated approach to cutaneous wound healing: vibrational microscopy and molecular biology. J Cell Mol Med 2009; 12:2145-54. [PMID: 19145704 PMCID: PMC4506178 DOI: 10.1111/j.1582-4934.2008.00459.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The repair of cutaneous wounds in the adult body involves a complex series of spatially and temporally organized processes to prevent infection and restore homeostasis. Three characteristic phases of wound repair (inflammation, proliferation including re-epithelialization and remodelling) overlap in time and space. We have utilized a human skin wound-healing model to correlate changes in genotype and pheno-type with infrared (IR) and confocal Raman spectroscopic images during the re-epithelialization of excisional wounds. The experimental protocols validated as IR images clearly delineate the keratin-rich migrating epithelial tongue from the collagen-rich wound bed. Multivariate statistical analysis of IR datasets acquired 6 days post-wounding reveal subtle spectral differences that map to distinct spatial distributions, which are correlated with immunofluorescent staining patterns of different keratin types. Images computed within collagen-rich regions expose complementary spatial patterns and identify elastin in the wound bed. The temporal sequence of events is explored through a comparison of gene array analysis with confocal Raman microscopy. Our approach demonstrates the feasibility of acquiring detailed molecular structure information from the various proteins and their subclasses involved in the wound-healing process.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, London, SW72AZ, UK
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31
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Abstract
Chemical imaging with Fourier transform infrared (FT-IR) spectroscopy allows the visualization of the distribution of chemical components in cells without the need for labels or added dyes. However, obtaining such images of living cells is difficult because of the strong absorption of water in the mid-infrared region. We report the use of attenuated total reflection (ATR) FT-IR spectroscopic imaging to study live human cancer cells in an aqueous environment, on a single cell level. Two complementary approaches have been used, providing flexibility with field of view and spatial resolution: (1) micro-ATR FT-IR imaging using a microscope objective with a Ge crystal, and (2) single-reflection diamond ATR-FT-IR imaging. Using both approaches, the ATR-FT-IR spectroscopic signatures allow the differentiation between several cellular organelles, e.g., the nucleus and the endoplasmic reticulum (ER). The overall cell shape can be defined by the distribution of the amide II band in the measured image, while the DNA-rich nucleus and glycogen-rich ER could be imaged using the spectral bands at 1084 cm(-1) and 1023 cm(-1), respectively. We also demonstrate the potential of ATR-FT-IR spectroscopic imaging for unraveling the details of the dynamics of biological processes, which are not accessible from cell ensemble studies, with high molecular specificity and satisfactory spatial resolution.
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Affiliation(s)
- Marina K Kuimova
- Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
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32
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Chan KLA, Kazarian SG. Attenuated total reflection-Fourier transform infrared imaging of large areas using inverted prism crystals and combining imaging and mapping. Appl Spectrosc 2008; 62:1095-1101. [PMID: 18926018 DOI: 10.1366/000370208786049042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Attenuated total reflection-Fourier transform infrared (ATR-FT-IR) imaging is a very useful tool for capturing chemical images of various materials due to the simple sample preparation and the ability to measure wet samples or samples in an aqueous environment. However, the size of the array detector used for image acquisition is often limited and there is usually a trade off between spatial resolution and the field of view (FOV). The combination of mapping and imaging can be used to acquire images with a larger FOV without sacrificing spatial resolution. Previous attempts have demonstrated this using an infrared microscope and a Germanium hemispherical ATR crystal to achieve images of up to 2.5 mm x 2.5 mm but with varying spatial resolution and depth of penetration across the imaged area. In this paper, we demonstrate a combination of mapping and imaging with a different approach using an external optics housing for large ATR accessories and inverted ATR prisms to achieve ATR-FT-IR images with a large FOV and reasonable spatial resolution. The results have shown that a FOV of 10 mm x 14 mm can be obtained with a spatial resolution of approximately 40-60 microm when using an accessory that gives no magnification. A FOV of 1.3 mm x 1.3 mm can be obtained with spatial resolution of approximately 15-20 microm when using a diamond ATR imaging accessory with 4x magnification. No significant change in image quality such as spatial resolution or depth of penetration has been observed across the whole FOV with this method and the measurement time was approximately 15 minutes for an image consisting of 16 image tiles.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
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33
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Chan KLA, Tay FH, Poulter G, Kazarian SG. Chemical imaging with variable angles of incidence using a diamond attenuated total reflection accessory. Appl Spectrosc 2008; 62:1102-1107. [PMID: 18926019 DOI: 10.1366/000370208786049222] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new development in Fourier transform infrared (FT-IR) imaging using a diamond attenuated total reflection (ATR) imaging accessory in a novel manner that allows the angle of incidence to be varied in order to obtain images from subsurface layers of different thickness is introduced. Chemical images of samples from the same area but with different depths of penetration are obtained by changing the angle of incidence as well as using different spectral bands at different wavenumbers. Changes in the angle of incidence with this accessory were made possible by taking advantage of the relatively large numerical aperture employed by the original imaging optics. This arrangement allowed us to introduce an additional movable aperture in the optical design to restrict the angle of incidence to certain values. Two samples have been studied, one for the calibration of the angle of incidence while the other demonstrates the capability of obtaining three-dimensional (3D) information using this approach. Advantages of this new approach include the relatively high spatial resolution (it can spatially resolve features as small as 12 mum without a microscope) and no change in the imaging area and sampling area during manipulation of the angle of incidence.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, SW7 2AZ, UK
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Chan KLA, Tay FH, Taylor C, Kazarian SG. A novel approach for study of in situ diffusion in human hair using Fourier transform infrared spectroscopic imaging. Appl Spectrosc 2008; 62:1041-1044. [PMID: 18801245 DOI: 10.1366/000370208785793263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
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Randle WL, Cha JM, Hwang YS, Chan KLA, Kazarian SG, Polak JM, Mantalaris A. Integrated 3-dimensional expansion and osteogenic differentiation of murine embryonic stem cells. ACTA ACUST UNITED AC 2008; 13:2957-70. [PMID: 17988191 DOI: 10.1089/ten.2007.0072] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Embryonic stem cell (ESC) culture is fragmented and laborious and involves operator decisions. Most protocols consist of 3 individual steps: maintenance, embryoid body (EB) formation, and differentiation. Integration will assist automation, ultimately aiding scale-up to clinically relevant numbers. These problems were addressed by encapsulating undifferentiated murine ESCs (mESCs) in 1.1% (w/v) low-viscosity alginic acid, 0.1% (v/v) porcine gelatin hydrogel beads (d = 2.3 mm). Six hundred beads containing 10,000 mESCs per bead were cultured in a 50-mL high-aspect-ratio vessel bioreactor. Bioreactor cultures were rotated at 17.5 revolutions per min, cultured in maintenance medium containing leukemia inhibitory factor for 3 days, replaced with EB formation medium for 5 days followed by osteogenic medium containing L-ascorbate-2-phosphate (50 microg/mL), beta-glycerophosphate (10 mM), and dexamethasone (1 microM) for an additional 21 days. After 29 days, 84 times as many cells per bead were observed and mineralized matrix was formed within the alginate beads. Osteogenesis was confirmed using von Kossa, Alizarin Red S staining, alkaline phosphatase activity, immunocytochemistry for osteocalcin, OB-cadherin, collagen type I, reverse transcriptase polymerase chain reaction, microcomputed tomography (micro-computed tomography) and Fourier transform infrared spectroscopic imaging. This simplified, integrated, and potentially scaleable methodology could enable the production of 3-demensional mineralized tissue from ESCs for potential clinical applications.
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Affiliation(s)
- Wesley L Randle
- Biological Systems Engineering Laboratory, Department of Chemical Engineering, Imperial College, London, United Kingdom.
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Andrew Chan KL, Kazarian SG. Chemical imaging of the stratum corneum under controlled humidity with the attenuated total reflection Fourier transform infrared spectroscopy method. J Biomed Opt 2007; 12:044010. [PMID: 17867814 DOI: 10.1117/1.2754686] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Attenuated total reflection Fourier transform infrared spectroscopic imaging was applied to study human stratum corneum (SC) tissue, the outermost layer of the skin. This imaging approach was combined with a controlled environment cell to demonstrate the possibility of obtaining chemical images of SC exposed to a wide range of relative humidities and diffusion of ethanol through the SC tissue with a specially designed liquid cell. The effect of water vapor sorbed into the SC on the distribution of other components in the SC was studied. Principal component analysis was applied in conjunction with univariate analysis to differentiate the distribution of different components in the SC. Swelling of the SC, a heterogeneous distribution of natural moisturizing factor and water, was detected upon the increase of relative humidity. The approach to image the penetration of liquid ethanol into the SC was also demonstrated and showed good potential and implications for studying transdermal drug delivery.
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Affiliation(s)
- K L Andrew Chan
- Imperial College London, Department of Chemical Engineering, London, SW7 2AZ, United Kingdom
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37
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Abstract
In situ attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopic imaging has been used to obtain chemical images of fingerprints under controlled humidity and temperature. The distribution of lipid and amino acid components in the fingerprints from different donors left on the surface of the ZnSe crystal has been studied using an in situ FT-IR spectroscopic imaging approach under a controlled environment and studied as a function of time. Univariate and multivariate analyses were employed to analyze the spectroscopic dataset. Changes in the spectra of lipids with temperature and time have been detected. This information is needed to understand aging of the fingerprints. The ATR-FT-IR spectroscopic imaging offers a new and complementary means for studying the chemistry of fingerprints that are left pristine for further analysis. This study demonstrates the potential for visualizing the chemical changes of fingerprints for forensic applications by spectroscopic imaging.
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Affiliation(s)
- Camilla Ricci
- Department of Chemical Engineering, Imperial College London, London, UK
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Abstract
FTIR spectroscopic imaging using a diamond ATR accessory has been applied to examine the influence of moisture and compression pressure on the density and components distribution of compacted pharmaceutical tablets. The model drug and excipient used within this study are ibuprofen and hydroxypropylmethylcellulose (HPMC). Chemical images of these compacted tablets were captured in situ without removing the tablet between measurements. A powder mixture of both, drug and excipient, prior to compaction, were subjected to a controlled environment, using a controlled humidity cell. Histograms were plotted to assess the density distribution quantitatively. This FTIR spectroscopic imaging approach enabled both measurement of water sorption and enhanced visualization of the density distribution of the compacted tablets.
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Affiliation(s)
- Noha Elkhider
- Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2AZ, UK
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Chan KLA, Kazarian SG. Attenuated total reflection Fourier transform infrared imaging with variable angles of incidence: a three-dimensional profiling of heterogeneous materials. Appl Spectrosc 2007; 61:48-54. [PMID: 17311716 DOI: 10.1366/000370207779701415] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Depth profiling in Fourier transform infrared (FT-IR) spectroscopic imaging has been demonstrated using a single reflection variable angle attenuated total reflection (ATR) accessory. Chemical information about samples can be obtained in three dimensions by acquiring ATR-FT-IR images at different angles of incidence through the ATR crystal. The image quality and field of view achieved at different angles of incidence has been discussed. A polymer film comprising two layers has been used as an example to demonstrate the principle of the measurement. The demonstrated approach is a promising tool to obtain depth profiles of heterogeneous materials. The extent of the measured depths is limited and ranges from approximately 0.3 to 4 microm, but the spatial resolution in the z-direction is not limited by diffraction. The development of this approach opens up the possibility to study the spatial heterogeneity of thin films including biological tissues, such as hair and skin, with high depth resolution.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, SW7 2AZ, UK
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40
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Ricci C, Chan KLA, Kazarian SG. Combining the tape-lift method and Fourier transform infrared spectroscopic imaging for forensic applications. Appl Spectrosc 2006; 60:1013-21. [PMID: 17002827 DOI: 10.1366/000370206778397434] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Conventional Fourier transform infrared (FT-IR) spectroscopy and microscopy have been widely used in forensic science. New opportunities exist to obtain chemical images and to enhance the spatial resolution using attenuated total reflection (ATR) FT-IR spectroscopy coupled with a focal-plane array (FPA) detector. In this paper, the sensitivity limits of FT-IR imaging using three different ATR crystals (Ge, ZnSe, and diamond) in three different optical arrangements for the detection of model particles is discussed. Model systems of ibuprofen and paracetamol particles having sizes below 32 mum were studied. The collection of drug particles was achieved with the aid of two different tapes: common adhesive tape and a film of polydimethylsiloxane (PDMS). The surface of the film with collected particles was measured directly via ATR-FT-IR imaging. Since the removal of tape from porous surfaces can be difficult, the application of micro ATR-FT-IR imaging directly to the surface of a newspaper contaminated with particles of model drugs is also discussed. In order to assess the feasibility of the chosen method in a forensic case study, the detection of diacetylmorphine hydrochloride traces in PDMS matrix and the finger surface is investigated. The scenarios considered were that of the detection of evidence collected at a crime scene with the tape lift method and the analysis of the finger of an individual after drug handling. The results show broad implications in the detection of drugs of abuse.
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Affiliation(s)
- Camilla Ricci
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
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Kazarian SG, Chan KLA. Applications of ATR-FTIR spectroscopic imaging to biomedical samples. Biochimica et Biophysica Acta (BBA) - Biomembranes 2006; 1758:858-67. [PMID: 16566893 DOI: 10.1016/j.bbamem.2006.02.011] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 02/11/2006] [Indexed: 11/26/2022]
Abstract
FTIR spectroscopic imaging in ATR (Attenuated Total Reflection) mode is a powerful tool for studying biomedical samples. This paper summarises recent advances in the applications of ATR-FTIR imaging to dissolution of pharmaceutical formulations and drug release. The use of two different ATR accessories to obtain chemical images of formulations in contact with water as a function of time is demonstrated. The innovative use of the diamond ATR accessory allowed in situ imaging of tablet compaction and dissolution. ATR-FTIR imaging was also applied to obtain images of the surface of skin and the spatial distribution of protein and lipid rich domains was obtained. Chemical images of cross-section of rabbit aorta were obtained using a diamond ATR accessory and the possibility of in situ imaging of arterial samples in contact with aqueous solution was demonstrated for the first time. This experiment opens an opportunity to image arterial samples in contact with solutions containing drug molecules. This approach may help in understanding the mechanisms of treatment of atherosclerosis.
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Affiliation(s)
- S G Kazarian
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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Abstract
Fourier transformed infrared (FTIR) spectroscopic imaging in combination with a novel attenuated total reflection (ATR) accessory with an expanded field of view has been applied to simultaneously obtain infrared spectra of more than 150 miniature samples, and to study the dissolution process of several different formulations in separate mini-channels simultaneously. This is the first time FTIR spectroscopic imaging using such an ATR accessory with an expanded field of view has been reported. The resultant imaging area with this approach was found to be ca. 15.4 x 21.4 mm(2) (6 x expansion). The potential of this approach includes imaging up to 440 samples simultaneously. The same accessory was used to prepare mini-channels (4 mm wide, 15 mm long and 0.5 mm deep) which were made of a PDMS grid that was self-adhered to the surface of the ATR crystal. Different molecular weights of poly(ethylene glycol) (PEG), with or without the addition of ibuprofen, have been used as model pharmaceutical formulations and chemical imaging of the simultaneous dissolution of five different formulations of PEG/ibuprofen has been demonstrated. Direct comparison between these different formulations under identical conditions was possible due to this imaging approach.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, United Kingdom SW7 2AZ
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Chan KLA, Kazarian SG. High-Throughput Study of Poly(ethylene glycol)/Ibuprofen Formulations under Controlled Environment Using FTIR Imaging. ACTA ACUST UNITED AC 2005; 8:26-31. [PMID: 16398550 DOI: 10.1021/cc050041x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Simultaneous analysis of many samples under identical conditions improves the effectiveness of research and accelerates product design. A novel spectroscopic imaging approach using a multichannel detector has been developed for parallel analysis of pharmaceutical formulations under controlled environments. Samples of formulations of ibuprofen in poly(ethylene glycol) have been prepared with ibuprofen concentrations ranging from 0 to 100% using a microdroplet deposition approach. The concentration of ibuprofen in PEG at which dimerization of ibuprofen molecules can be avoided has been determined via simultaneous measurement of all samples using in situ FTIR spectroscopic imaging. FTIR spectra from all samples have been analyzed to assess the molecular state of the drug and the degree of polymer swelling as a function of drug concentration. The effect of elevated temperature on the stability of all formulations was also studied. This high-throughput approach identified the concentration range for stable formulations and provided evidence that hydrogen bonding between ibuprofen and the polymer is responsible for enhanced stability at higher temperatures. This high-throughput imaging approach, based on a miniature sampling system, significantly reduces the experimental time by allowing many (potentially a few thousand) experiments to be run in parallel and increases the accuracy by minimizing variations between experiments.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, SW7 2AZ UK
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Abstract
FTIR spectroscopy is one of the most powerful methods for material characterization. However, the sensitivity of this analytical tool is often very limited especially for materials with weak infrared absorption or when spectral bands of the targeted trace material overlap with the spectral bands of major components. Fortunately, for heterogeneous samples, there is an opportunity to improve the sensitivity of detection by using an imaging approach. This paper explores the opportunity of enhancing the sensitivity of FTIR spectroscopy to detect trace amounts of materials using the FTIR imaging approach based on a focal plane array (FPA) detector. Model sample tablets of ibuprofen in hydroxypropyl methylcellulose (HPMC) have been used to exemplify the detection limits of FTIR spectroscopy using: (a) a conventional mercury cadmium telluride (MCT) detector and (b) a FPA detector. The sensitivity level was compared and it has been found that for this particular set of samples, the lowest concentration of ibuprofen in HPMC that can be detected using attenuated total reflection (ATR) measuring mode with the single element MCT detector was 0.35 wt% while using the FPA detector, the presence of drug has been detected in a sample that contains as little as 0.075 wt% of drug. The application of using this enhanced sensitivity offered by the multi-channel detector to probe trace amounts of drug particles left on the surface of a finger after handling a small amount of the drug has also been demonstrated. These results have broad implications for forensic, biomedical and pharmaceutical research.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, UKSW7 2AZ
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Abstract
Fourier transform infrared (FTIR) spectroscopic imaging with infrared array detectors has recently emerged as a powerful materials characterization tool. We report a novel application of FTIR imaging for high-throughput analysis of materials under controlled environment. This approach combines the use of spectroscopic imaging with an attenuated total reflection (ATR)-IR cell, microdroplet sample deposition system, and a device that controls humidity inside the cell. By this approach, it was possible to obtain "chemical snapshots" from a spatially defined array of many different polymer/drug formulations (more than 100) under identical conditions. This method provides direct measurement of materials properties for high-throughput formulation design and optimization. Simultaneous response (water sorption, crystallization, etc.) of the array of formulations to the environmental parameters was studied. Implications of the presented approach range from studies of smart polymeric materials and sensors to screening of pharmaceuticals and biomaterials.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, South Kensington Campus, Imperial College London, London SW7 2AZ, United Kingdom
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Chan KLA, Kazarian SG, Mavraki A, Williams DR. Fourier transform infrared imaging of human hair with a high spatial resolution without the use of a synchrotron. Appl Spectrosc 2005; 59:149-155. [PMID: 15720754 DOI: 10.1366/0003702053085070] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The cross-section of a human hair has been imaged for the first time using the micro attenuated total reflection (ATR) Fourier transformed infrared (FT-IR) method in combination with a focal plane array (FPA) detector. A rigorous approach was applied to determine the spatial resolution, namely, measuring the distance over which the band absorbance changes from 95 to 5% of the maximum absorbance when passing through a sharp interface. The measured value for IR transmission was approximately 16 microm, while the value obtained using ATR imaging was approximately 5 microm. The enhanced spatial resolution achieved by this method allows the medulla of the hair (approximately 8 microm in diameter) to be imaged clearly without the need for a synchrotron source. The spatial resolution of transmission and ATR imaging is compared, and advantages of ATR imaging are discussed.
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Affiliation(s)
- K L A Chan
- Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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Kazarian SG, Chan KLA, Maquet V, Boccaccini AR. Characterisation of bioactive and resorbable polylactide/Bioglass composites by FTIR spectroscopic imaging. Biomaterials 2004; 25:3931-8. [PMID: 15046883 DOI: 10.1016/j.biomaterials.2003.10.099] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2003] [Accepted: 10/10/2003] [Indexed: 11/21/2022]
Abstract
Formation, size and distribution of hydroxyapatite domains in resorbable composites made of poly(DL-lactide) foams and Bioglass particles after exposure to a solution of phosphate-buffer saline (PBS) for different periods of time have been analysed with FTIR imaging using the micro-ATR-IR approach. The spectral information of 4096 spectra measured simultaneously with the IR microscope equipped with a focal plane infrared array detector allowed us to obtain chemical images showing the distribution of Bioglass particles in the composites. FTIR imaging in micro-ATR mode allowed to obtain images with enhanced spatial resolution. A random distribution of hydroxyapatite domains with average size of ca. 10 microm on the surface of the composites was found after exposure to PBS for 14 and 28 days. The further growth of the hydroxyapatite domains after exposure to PBS for 63 days was detected. The spectroscopic imaging method introduced here promises to become a powerful method for characterisation of resorbable polymer composites containing bioactive inorganic phases developed for bone tissue engineering scaffolds. The accurate detection of hydroxyapatite domains and the imaging of their location in the scaffold structure is required to provide an assessment of the composites bioactivity.
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Affiliation(s)
- Sergei G Kazarian
- Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2BY, UK.
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Affiliation(s)
- Andreas Gupper
- Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - K. L. Andrew Chan
- Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Sergei G. Kazarian
- Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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Abstract
FTIR imaging was applied to study solid dispersions of a poorly water-soluble drug in poly(ethylene glycol) (PEG) and dissolution in water. It has been shown that initially amorphous nifedipine crystallizes within PEG-8000 for formulations with a drug loading of at least 10 wt%. The formation of a significant amount of crystalline drug within the polymer matrix reduces the rate of dissolution of the drug. This FTIR spectroscopic imaging in the ATR mode provides novel insight into the mechanism of dissolution of nifedipine from solid dispersions in water-soluble polymers, which is valuable in optimization of manufacturing these formulations.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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Affiliation(s)
- Sergei G. Kazarian
- Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2AZ, UK
| | - K. L. Andrew Chan
- Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2AZ, UK
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