Hugh Byrne | Dublin Institute of Technology (original) (raw)
Papers by Hugh Byrne
Http Dx Doi Org 10 1667 Rr1836 1, Jan 22, 2010
The scientific literature currently contains an ever growing number of reports of applications of... more The scientific literature currently contains an ever growing number of reports of applications of vibrational spectroscopy as a multivariate non-invasive tool for analysis of biological effects at the molecular level. Recently, Fourier Transform Infrared Microspectroscopy (FTIRM) has been demonstrated to be sensitive to molecular events occurring in cells and tissue post-exposure to ionising radiation. In this work the application of FTIRM in the examination of dose dependent molecular effects occurring in skin cells post exposure to ionising radiation, with the use of partial least squares regression (PLSR) and generalized regression neural networks (GRNN) is studied. The methodology is shown to be sensitive to molecular events occurring with radiation dose and time after exposure. The variation in molecular species with dose and time after irradiation is shown to be non-linear by virtue of the higher modelling efficiency yielded from the non-linear algorithms. Dose prediction efficiencies of approximately ±10mGy
Interest in developing robust, quicker and easier diagnostic tests for cancer has lead to an incr... more Interest in developing robust, quicker and easier diagnostic tests for cancer has lead to an increased use of Fourier transform infrared (FTIR) spectroscopy to meet that need. In this study we present the use of different experimental modes of infrared spectroscopy to investigate the RWPE human prostate epithelial cell line family which are derived from the same source but differ in their mode of transformation and their mode of invasive phenotype. Importantly, analysis of the infrared spectra obtained using different experimental modes of infrared spectroscopy produce similar results. The RWPE family of cell lines can be separated into groups based upon the method of cell transformation rather than the resulting invasiveness/aggressiveness of the cell line. The study also demonstrates the possibility of using a genetic algorithm as a possible standardised pre-processing step and raises the important question of the usefulness of cell lines to create a biochemical model of prostate cancer progression.
Journal of Materials Chemistry B
A highly-sensitive SERS immunosensor, easily fabricated by merging: (i) plasmonic gold nanostars ... more A highly-sensitive SERS immunosensor, easily fabricated by merging: (i) plasmonic gold nanostars in SERS-immunotags; (ii) highly active capture antibodies in a regenerated cellulose hydrogel platform; and (iii) CLS method for SERS data analysis.
Molecules
Raman spectroscopy is a label-free, non-destructive, non-invasive analytical tool that provides i... more Raman spectroscopy is a label-free, non-destructive, non-invasive analytical tool that provides insight into the molecular composition of samples with minimum or no sample preparation. The increased availability of commercial portable Raman devices presents a potentially easy and convenient analytical solution for day-to-day analysis in laboratories and production lines. However, their performance for highly specific and sensitive analysis applications has not been extensively evaluated. This study performs a direct comparison of such a commercially available, portable Raman system, with a research grade Raman microscope system for the analysis of water content of Natural Deep Eutectic Solvents (NADES). NADES are renewable, biodegradable and easily tunable “green” solvents, outcompeting existing organic solvents for applications in extraction from biomass, biocatalysis, and nanoparticle synthesis. Water content in NADES is, however, a critical parameter, affecting their properties, ...
Frontiers in Bioengineering and Biotechnology
Molecules
Stem cell technology has attracted considerable attention over recent decades due to its enormous... more Stem cell technology has attracted considerable attention over recent decades due to its enormous potential in regenerative medicine and disease therapeutics. Studying the underlying mechanisms of stem cell differentiation and tissue generation is critical, and robust methodologies and different technologies are required. Towards establishing improved understanding and optimised triggering and control of differentiation processes, analytical techniques such as flow cytometry, immunohistochemistry, reverse transcription polymerase chain reaction, RNA in situ hybridisation analysis, and fluorescence-activated cell sorting have contributed much. However, progress in the field remains limited because such techniques provide only limited information, as they are only able to address specific, selected aspects of the process, and/or cannot visualise the process at the subcellular level. Additionally, many current analytical techniques involve the disruption of the investigation process (t...
International Journal of Molecular Sciences
Lateral flow immunochromatographic assays are a powerful diagnostic tool for point-of-care tests,... more Lateral flow immunochromatographic assays are a powerful diagnostic tool for point-of-care tests, based on their simplicity, specificity, and sensitivity. In this study, a rapid and sensitive gold nanoparticle (AuNP) immunochromatographic strip is produced for detecting aflatoxin B1 (AFB1) in suspicious fungi-contaminated food samples. The 10 nm AuNPs were encompassed by bovine serum albumin (BSA) and AFB1 antibody. Thin-layer chromatography, gel electrophoresis and nuclear magnetic resonance spectroscopy were employed for analysing the chemical complexes. Various concentrations of AFB1 antigen (0–16 ng/mL) were tested with AFB1 antibody–BSA–AuNPs (conjugated AuNPs) and then analysed by scanning electron microscopy, ultraviolet–visible spectroscopy, and Zetasizer. The results showed that the AFB1 antibody was coupled to BSA by the N-hydroxysuccinimide ester method. The AuNPs application has the potential to contribute to AFB1 detection by monitoring a visible colour change from red ...
2D Materials
In-vitro localisation and degradation of few-layer MoS2 submicrometric plates in human macrophage... more In-vitro localisation and degradation of few-layer MoS2 submicrometric plates in human macrophage-like cells: a label free Raman micro-spectroscopic study
Nanomaterials
Immunoassays using Surface-Enhanced Raman Spectroscopy are especially interesting on account not ... more Immunoassays using Surface-Enhanced Raman Spectroscopy are especially interesting on account not only of their increased sensitivity, but also due to its easy translation to point-of-care formats. The bases for these assays are bioconjugates of polyclonal antibodies and anisotropic gold nanoparticles functionalized with a Raman reporter. These bioconjugates, once loaded with the antigen analyte, can react on a sandwich format with the same antibodies immobilized on a surface. This surface can then be used for detection, on a microfluidics or immunochromatographic platform. Here, we have assembled bioconjugates of gold nanostars functionalized with 4-mercaptobenzoic acid, and anti-horseradish peroxidase antibodies. The assembly was by simple incubation, and agarose gel electrophoresis determined a high gold nanostar to antibody binding constant. The functionality of the bioconjugates is easy to determine since the respective antigen presents peroxidase enzymatic activity. Furthermore...
PloS one, 2018
It is now well accepted that radiation induced bystander effects can occur in cells exposed to me... more It is now well accepted that radiation induced bystander effects can occur in cells exposed to media from irradiated cells. The aim of this study was to follow the bystander cells in real time following addition of media from irradiated cells and to determine the effect of inhibiting these signals. A human keratinocyte cell line, HaCaT cells, was irradiated (0.005, 0.05 and 0.5 Gy) with γ irradiation, conditioned medium was harvested after one hour and added to recipient bystander cells. Reactive oxygen species, nitric oxide, Glutathione levels, caspase activation, cytotoxicity and cell viability was measured after the addition of irradiated cell conditioned media to bystander cells. Reactive oxygen species and nitric oxide levels in bystander cells treated with 0.5Gy ICCM were analysed in real time using time lapse fluorescence microscopy. The levels of reactive oxygen species were also measured in real time after the addition of extracellular signal-regulated kinase and c-Jun amin...
International journal of environmental research and public health, Jan 10, 2018
The 21st century has truly become the age of nanotechnology. Nanomaterials, design strategies, an... more The 21st century has truly become the age of nanotechnology. Nanomaterials, design strategies, and processing have already made a significant impact in areas of materials science and electronics, with many commercial applications already being available on the consumer market[...].
Journal of biophotonics, 2018
This overview groups some of the recent studies highlighting the potential application of Raman m... more This overview groups some of the recent studies highlighting the potential application of Raman microspectroscopy as an analytical technique in preclinical development to predict drug mechanism of action and in clinical application as a companion diagnostic and in personalised therapy due to its capacity to predict cellular resistance and therefore to optimise chemotherapeutic treatment efficacy. Notably, the anthracyclines, doxorubicin and actinomycin D, elicit similar spectroscopic signatures of subcellular interaction characteristic of the mode of action of intercalation. Although cisplatin and vincristine show markedly different signatures, at low exposure doses, their signatures at higher doses show marked similarities to those elicited by the intercalating anthracyclines, confirming that anticancer agents can have different modes of action with different spectroscopic signatures, depending on the dose. The study demonstrates that Raman microspectroscopy can elucidate subcellul...
Biochimica et biophysica acta, Feb 1, 2018
The accumulation of vascular smooth muscle (SMC)-like cells and stem cell-derived myogenic and os... more The accumulation of vascular smooth muscle (SMC)-like cells and stem cell-derived myogenic and osteogenic progeny contributes significantly to arteriosclerotic disease. This study established whether label-free vibrational spectroscopy can discriminate de-differentiated 'synthetic' SMCs from undifferentiated stem cells and their myogenic and osteogenic progeny in vitro, compared with conventional immunocytochemical and genetic analyses. TGF-β1- and Jagged1-induced myogenic differentiation of CD44+ mesenchymal stem cells was confirmed in vitro by immunocytochemical analysis of specific SMC differentiation marker expression (α-actin, calponin and myosin heavy chain 11), an epigenetic histone mark (H3K4me2) at the myosin heavy chain 11 locus, promoter transactivation and mRNA transcript levels. Osteogenic differentiation was confirmed by alizarin red staining of calcium deposition. Fourier Transform Infrared (FTIR) maps facilitated initial screening and discrimination while Ram...
Experimental and molecular pathology, Dec 1, 2017
Raman spectroscopy can provide a molecular-level signature of the biochemical composition and str... more Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with submicrometer spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400-1800cm-1) has been shown to be very promising for optical biopsy purposes. However, limitations for discrimination of dysplastic and inflammatory processes based on the fingerprint region have been demonstrated. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber region (2800-3600cm-1) provides more specific information based on NH, OH and CH vibrations and can be used to identify the subtle changes which could be important for discrimination of samples. In this study, we demonstrate the potential of the high-wavenumber spectral region in this context...
Journal of Biophotonics
Raman micro-spectroscopy is a non-invasive, in vitro analytical tool which is being increasingly ... more Raman micro-spectroscopy is a non-invasive, in vitro analytical tool which is being increasingly explored for its potential in clinical applications and monitoring the uptake, mechanism of action and cellular interaction at a molecular level of chemotherapeutic drugs, ultimately as a potential label-free preclinical screening and companion diagnostic tool. In this study, Doxorubicin (DOX), a "gold standard" chemotherapeutic drug, is employed as a model in the in vitro lung cancer cell line, A549, in order to demonstrate the potential of Raman micro-spectroscopy to screen and identify spectroscopic markers of its trafficking and mechanism of action. Confocal Laser Scanning Microscopy (CLSM) was used in parallel to illustrate the uptake and subcellular localisation, and cytotoxicity assays were employed to establish the toxicity profiles for early and late exposure times of A549 to DOX. Multivariate statistical analysis, consisting of principal components analysis (PCA), partial least squares regression (PLSR) and independent component analysis (ICA) were used to elucidate the spectroscopic signatures associated with DOX uptake and subcellular interaction. Raman spectroscopic profiling illustrates both drug kinetics and its pharmacodynamics in the cell and associated biochemical changes, demonstrating that DOX is mainly localised in the nuclear area, saturating the nucleolus first, within ~6hrs of exposure, before the surrounding nuclear areas after ~12hrs, and only accumulates in the cytoplasm after 48hrs. PLSR over varying time intervals enables identification of DOX-DNA binding at early stages of exposure (0-12hrs), while regression over the longer time periods (24-72hrs) reveals spectroscopic signatures associated with the metabolic cellular response.
AIP Conference Proceedings
Single wall carbon nanotubes are insoluble in most organic solvents such as toluene. Improvements... more Single wall carbon nanotubes are insoluble in most organic solvents such as toluene. Improvements in the solubility of the single wall carbon nanotubes are however seen as a result of specific interactions with dye molecules such as terphenyl and anthracene. Suspensions formed in toluene with these dye molecules and the single wall carbon nanotubes are seen to be stable over
Synthetic Metals
Time resolved photoluminescence studies have been carried out in films, powders and single crysta... more Time resolved photoluminescence studies have been carried out in films, powders and single crystals of Cs0. The observed spectra for Cso in all forms are consistent with those reported for steady state conditions and may be associated with an intramolecular process. The spectrum is largely temperature independent with the exception of a broadening of the high energy edge with increasing temperature. At low temperatures, the observed Cs0 luminescence decays rapidly with a lifetime of 1.2 ns and can be interpreted as a low efficiency singlet decay or a decay from the molecules on the surface of the microcrystallites. No long lived decay from the triplet is observable at these intensities. In the case of the films, both the emission spectrum and lifetime are independent of excitation intensity. In the case of the powder and crystal a dramatic increase in the lifetime and broadening of the spectrum is observed at higher intensities. This broadened spectrum shows no fine structure and the emission maximum is red shifted by ~0.4 eV. Above a 'threshold' intensity, the luminescence intensity is seen to increase with the cube of the input intensity. This behaviour is interpreted as an abrupt onset of emission from the highly populated triplet state. The restrictions of the transition selection rules are relaxed by a banding of the intramolecular triplet states, a process which is dependent on a critical excited state population density. Thus a transition from intramolecular processes to an extended state, band like behaviour is observable at high excitation densities.
MRS Proceedings
ABSTRACTThe excited state properties of C60 thin films have been probed in the temperature range ... more ABSTRACTThe excited state properties of C60 thin films have been probed in the temperature range 77–273K using Raman spectroscopy. The change in the Raman, 2Ag mode of C60 (whose position is largely independent of temperature) was monitored as a function of the excitation intensity at 514.5nm. This mode normally positioned at 1469cm-1, was seen to shift reversibly to a lower Raman frequency with increasing laser intensity. Two excited state species have been identified. The first, at 1466cm-1 has been associated with the molecular triplet of C60. The second species at 1463cm-1, has been speculated to be an excited state co-operative involving two or more excited states in the solid and is seen to be intrinsic to solid state C60 below the phase transition.
Journal of food science, 2017
The chicken- or fish-derived tripeptide, leucine-lysine-proline (LKP), inhibits the angiotensin c... more The chicken- or fish-derived tripeptide, leucine-lysine-proline (LKP), inhibits the angiotensin converting enzyme and may be used as an alternative treatment for prehypertension. However, it has low permeation across the small intestine. The formulation of LKP into a nanoparticle (NP) has the potential to address this issue. LKP-loaded NPs were produced using an ionotropic gelation technique, using chitosan (CL113). Following optimization of unloaded NPs, a mixture amount design was constructed using variable concentration of CL113 and tripolyphosphate at a fixed LKP concentration. Resultant particle sizes ranged from 120 to 271 nm, zeta potential values from 29 to 37 mV, and polydispersity values from 0.3 to 0.6. A ratio of 6:1 (CL113:TPP) produced the best encapsulation of approximately 65%. Accelerated studies of the loaded NPs indicated stability under normal storage conditions (room temperature). Cytotoxicity assessment showed no significant loss of cell viability and in vitro ...
Http Dx Doi Org 10 1667 Rr1836 1, Jan 22, 2010
The scientific literature currently contains an ever growing number of reports of applications of... more The scientific literature currently contains an ever growing number of reports of applications of vibrational spectroscopy as a multivariate non-invasive tool for analysis of biological effects at the molecular level. Recently, Fourier Transform Infrared Microspectroscopy (FTIRM) has been demonstrated to be sensitive to molecular events occurring in cells and tissue post-exposure to ionising radiation. In this work the application of FTIRM in the examination of dose dependent molecular effects occurring in skin cells post exposure to ionising radiation, with the use of partial least squares regression (PLSR) and generalized regression neural networks (GRNN) is studied. The methodology is shown to be sensitive to molecular events occurring with radiation dose and time after exposure. The variation in molecular species with dose and time after irradiation is shown to be non-linear by virtue of the higher modelling efficiency yielded from the non-linear algorithms. Dose prediction efficiencies of approximately ±10mGy
Interest in developing robust, quicker and easier diagnostic tests for cancer has lead to an incr... more Interest in developing robust, quicker and easier diagnostic tests for cancer has lead to an increased use of Fourier transform infrared (FTIR) spectroscopy to meet that need. In this study we present the use of different experimental modes of infrared spectroscopy to investigate the RWPE human prostate epithelial cell line family which are derived from the same source but differ in their mode of transformation and their mode of invasive phenotype. Importantly, analysis of the infrared spectra obtained using different experimental modes of infrared spectroscopy produce similar results. The RWPE family of cell lines can be separated into groups based upon the method of cell transformation rather than the resulting invasiveness/aggressiveness of the cell line. The study also demonstrates the possibility of using a genetic algorithm as a possible standardised pre-processing step and raises the important question of the usefulness of cell lines to create a biochemical model of prostate cancer progression.
Journal of Materials Chemistry B
A highly-sensitive SERS immunosensor, easily fabricated by merging: (i) plasmonic gold nanostars ... more A highly-sensitive SERS immunosensor, easily fabricated by merging: (i) plasmonic gold nanostars in SERS-immunotags; (ii) highly active capture antibodies in a regenerated cellulose hydrogel platform; and (iii) CLS method for SERS data analysis.
Molecules
Raman spectroscopy is a label-free, non-destructive, non-invasive analytical tool that provides i... more Raman spectroscopy is a label-free, non-destructive, non-invasive analytical tool that provides insight into the molecular composition of samples with minimum or no sample preparation. The increased availability of commercial portable Raman devices presents a potentially easy and convenient analytical solution for day-to-day analysis in laboratories and production lines. However, their performance for highly specific and sensitive analysis applications has not been extensively evaluated. This study performs a direct comparison of such a commercially available, portable Raman system, with a research grade Raman microscope system for the analysis of water content of Natural Deep Eutectic Solvents (NADES). NADES are renewable, biodegradable and easily tunable “green” solvents, outcompeting existing organic solvents for applications in extraction from biomass, biocatalysis, and nanoparticle synthesis. Water content in NADES is, however, a critical parameter, affecting their properties, ...
Frontiers in Bioengineering and Biotechnology
Molecules
Stem cell technology has attracted considerable attention over recent decades due to its enormous... more Stem cell technology has attracted considerable attention over recent decades due to its enormous potential in regenerative medicine and disease therapeutics. Studying the underlying mechanisms of stem cell differentiation and tissue generation is critical, and robust methodologies and different technologies are required. Towards establishing improved understanding and optimised triggering and control of differentiation processes, analytical techniques such as flow cytometry, immunohistochemistry, reverse transcription polymerase chain reaction, RNA in situ hybridisation analysis, and fluorescence-activated cell sorting have contributed much. However, progress in the field remains limited because such techniques provide only limited information, as they are only able to address specific, selected aspects of the process, and/or cannot visualise the process at the subcellular level. Additionally, many current analytical techniques involve the disruption of the investigation process (t...
International Journal of Molecular Sciences
Lateral flow immunochromatographic assays are a powerful diagnostic tool for point-of-care tests,... more Lateral flow immunochromatographic assays are a powerful diagnostic tool for point-of-care tests, based on their simplicity, specificity, and sensitivity. In this study, a rapid and sensitive gold nanoparticle (AuNP) immunochromatographic strip is produced for detecting aflatoxin B1 (AFB1) in suspicious fungi-contaminated food samples. The 10 nm AuNPs were encompassed by bovine serum albumin (BSA) and AFB1 antibody. Thin-layer chromatography, gel electrophoresis and nuclear magnetic resonance spectroscopy were employed for analysing the chemical complexes. Various concentrations of AFB1 antigen (0–16 ng/mL) were tested with AFB1 antibody–BSA–AuNPs (conjugated AuNPs) and then analysed by scanning electron microscopy, ultraviolet–visible spectroscopy, and Zetasizer. The results showed that the AFB1 antibody was coupled to BSA by the N-hydroxysuccinimide ester method. The AuNPs application has the potential to contribute to AFB1 detection by monitoring a visible colour change from red ...
2D Materials
In-vitro localisation and degradation of few-layer MoS2 submicrometric plates in human macrophage... more In-vitro localisation and degradation of few-layer MoS2 submicrometric plates in human macrophage-like cells: a label free Raman micro-spectroscopic study
Nanomaterials
Immunoassays using Surface-Enhanced Raman Spectroscopy are especially interesting on account not ... more Immunoassays using Surface-Enhanced Raman Spectroscopy are especially interesting on account not only of their increased sensitivity, but also due to its easy translation to point-of-care formats. The bases for these assays are bioconjugates of polyclonal antibodies and anisotropic gold nanoparticles functionalized with a Raman reporter. These bioconjugates, once loaded with the antigen analyte, can react on a sandwich format with the same antibodies immobilized on a surface. This surface can then be used for detection, on a microfluidics or immunochromatographic platform. Here, we have assembled bioconjugates of gold nanostars functionalized with 4-mercaptobenzoic acid, and anti-horseradish peroxidase antibodies. The assembly was by simple incubation, and agarose gel electrophoresis determined a high gold nanostar to antibody binding constant. The functionality of the bioconjugates is easy to determine since the respective antigen presents peroxidase enzymatic activity. Furthermore...
PloS one, 2018
It is now well accepted that radiation induced bystander effects can occur in cells exposed to me... more It is now well accepted that radiation induced bystander effects can occur in cells exposed to media from irradiated cells. The aim of this study was to follow the bystander cells in real time following addition of media from irradiated cells and to determine the effect of inhibiting these signals. A human keratinocyte cell line, HaCaT cells, was irradiated (0.005, 0.05 and 0.5 Gy) with γ irradiation, conditioned medium was harvested after one hour and added to recipient bystander cells. Reactive oxygen species, nitric oxide, Glutathione levels, caspase activation, cytotoxicity and cell viability was measured after the addition of irradiated cell conditioned media to bystander cells. Reactive oxygen species and nitric oxide levels in bystander cells treated with 0.5Gy ICCM were analysed in real time using time lapse fluorescence microscopy. The levels of reactive oxygen species were also measured in real time after the addition of extracellular signal-regulated kinase and c-Jun amin...
International journal of environmental research and public health, Jan 10, 2018
The 21st century has truly become the age of nanotechnology. Nanomaterials, design strategies, an... more The 21st century has truly become the age of nanotechnology. Nanomaterials, design strategies, and processing have already made a significant impact in areas of materials science and electronics, with many commercial applications already being available on the consumer market[...].
Journal of biophotonics, 2018
This overview groups some of the recent studies highlighting the potential application of Raman m... more This overview groups some of the recent studies highlighting the potential application of Raman microspectroscopy as an analytical technique in preclinical development to predict drug mechanism of action and in clinical application as a companion diagnostic and in personalised therapy due to its capacity to predict cellular resistance and therefore to optimise chemotherapeutic treatment efficacy. Notably, the anthracyclines, doxorubicin and actinomycin D, elicit similar spectroscopic signatures of subcellular interaction characteristic of the mode of action of intercalation. Although cisplatin and vincristine show markedly different signatures, at low exposure doses, their signatures at higher doses show marked similarities to those elicited by the intercalating anthracyclines, confirming that anticancer agents can have different modes of action with different spectroscopic signatures, depending on the dose. The study demonstrates that Raman microspectroscopy can elucidate subcellul...
Biochimica et biophysica acta, Feb 1, 2018
The accumulation of vascular smooth muscle (SMC)-like cells and stem cell-derived myogenic and os... more The accumulation of vascular smooth muscle (SMC)-like cells and stem cell-derived myogenic and osteogenic progeny contributes significantly to arteriosclerotic disease. This study established whether label-free vibrational spectroscopy can discriminate de-differentiated 'synthetic' SMCs from undifferentiated stem cells and their myogenic and osteogenic progeny in vitro, compared with conventional immunocytochemical and genetic analyses. TGF-β1- and Jagged1-induced myogenic differentiation of CD44+ mesenchymal stem cells was confirmed in vitro by immunocytochemical analysis of specific SMC differentiation marker expression (α-actin, calponin and myosin heavy chain 11), an epigenetic histone mark (H3K4me2) at the myosin heavy chain 11 locus, promoter transactivation and mRNA transcript levels. Osteogenic differentiation was confirmed by alizarin red staining of calcium deposition. Fourier Transform Infrared (FTIR) maps facilitated initial screening and discrimination while Ram...
Experimental and molecular pathology, Dec 1, 2017
Raman spectroscopy can provide a molecular-level signature of the biochemical composition and str... more Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with submicrometer spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400-1800cm-1) has been shown to be very promising for optical biopsy purposes. However, limitations for discrimination of dysplastic and inflammatory processes based on the fingerprint region have been demonstrated. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber region (2800-3600cm-1) provides more specific information based on NH, OH and CH vibrations and can be used to identify the subtle changes which could be important for discrimination of samples. In this study, we demonstrate the potential of the high-wavenumber spectral region in this context...
Journal of Biophotonics
Raman micro-spectroscopy is a non-invasive, in vitro analytical tool which is being increasingly ... more Raman micro-spectroscopy is a non-invasive, in vitro analytical tool which is being increasingly explored for its potential in clinical applications and monitoring the uptake, mechanism of action and cellular interaction at a molecular level of chemotherapeutic drugs, ultimately as a potential label-free preclinical screening and companion diagnostic tool. In this study, Doxorubicin (DOX), a "gold standard" chemotherapeutic drug, is employed as a model in the in vitro lung cancer cell line, A549, in order to demonstrate the potential of Raman micro-spectroscopy to screen and identify spectroscopic markers of its trafficking and mechanism of action. Confocal Laser Scanning Microscopy (CLSM) was used in parallel to illustrate the uptake and subcellular localisation, and cytotoxicity assays were employed to establish the toxicity profiles for early and late exposure times of A549 to DOX. Multivariate statistical analysis, consisting of principal components analysis (PCA), partial least squares regression (PLSR) and independent component analysis (ICA) were used to elucidate the spectroscopic signatures associated with DOX uptake and subcellular interaction. Raman spectroscopic profiling illustrates both drug kinetics and its pharmacodynamics in the cell and associated biochemical changes, demonstrating that DOX is mainly localised in the nuclear area, saturating the nucleolus first, within ~6hrs of exposure, before the surrounding nuclear areas after ~12hrs, and only accumulates in the cytoplasm after 48hrs. PLSR over varying time intervals enables identification of DOX-DNA binding at early stages of exposure (0-12hrs), while regression over the longer time periods (24-72hrs) reveals spectroscopic signatures associated with the metabolic cellular response.
AIP Conference Proceedings
Single wall carbon nanotubes are insoluble in most organic solvents such as toluene. Improvements... more Single wall carbon nanotubes are insoluble in most organic solvents such as toluene. Improvements in the solubility of the single wall carbon nanotubes are however seen as a result of specific interactions with dye molecules such as terphenyl and anthracene. Suspensions formed in toluene with these dye molecules and the single wall carbon nanotubes are seen to be stable over
Synthetic Metals
Time resolved photoluminescence studies have been carried out in films, powders and single crysta... more Time resolved photoluminescence studies have been carried out in films, powders and single crystals of Cs0. The observed spectra for Cso in all forms are consistent with those reported for steady state conditions and may be associated with an intramolecular process. The spectrum is largely temperature independent with the exception of a broadening of the high energy edge with increasing temperature. At low temperatures, the observed Cs0 luminescence decays rapidly with a lifetime of 1.2 ns and can be interpreted as a low efficiency singlet decay or a decay from the molecules on the surface of the microcrystallites. No long lived decay from the triplet is observable at these intensities. In the case of the films, both the emission spectrum and lifetime are independent of excitation intensity. In the case of the powder and crystal a dramatic increase in the lifetime and broadening of the spectrum is observed at higher intensities. This broadened spectrum shows no fine structure and the emission maximum is red shifted by ~0.4 eV. Above a 'threshold' intensity, the luminescence intensity is seen to increase with the cube of the input intensity. This behaviour is interpreted as an abrupt onset of emission from the highly populated triplet state. The restrictions of the transition selection rules are relaxed by a banding of the intramolecular triplet states, a process which is dependent on a critical excited state population density. Thus a transition from intramolecular processes to an extended state, band like behaviour is observable at high excitation densities.
MRS Proceedings
ABSTRACTThe excited state properties of C60 thin films have been probed in the temperature range ... more ABSTRACTThe excited state properties of C60 thin films have been probed in the temperature range 77–273K using Raman spectroscopy. The change in the Raman, 2Ag mode of C60 (whose position is largely independent of temperature) was monitored as a function of the excitation intensity at 514.5nm. This mode normally positioned at 1469cm-1, was seen to shift reversibly to a lower Raman frequency with increasing laser intensity. Two excited state species have been identified. The first, at 1466cm-1 has been associated with the molecular triplet of C60. The second species at 1463cm-1, has been speculated to be an excited state co-operative involving two or more excited states in the solid and is seen to be intrinsic to solid state C60 below the phase transition.
Journal of food science, 2017
The chicken- or fish-derived tripeptide, leucine-lysine-proline (LKP), inhibits the angiotensin c... more The chicken- or fish-derived tripeptide, leucine-lysine-proline (LKP), inhibits the angiotensin converting enzyme and may be used as an alternative treatment for prehypertension. However, it has low permeation across the small intestine. The formulation of LKP into a nanoparticle (NP) has the potential to address this issue. LKP-loaded NPs were produced using an ionotropic gelation technique, using chitosan (CL113). Following optimization of unloaded NPs, a mixture amount design was constructed using variable concentration of CL113 and tripolyphosphate at a fixed LKP concentration. Resultant particle sizes ranged from 120 to 271 nm, zeta potential values from 29 to 37 mV, and polydispersity values from 0.3 to 0.6. A ratio of 6:1 (CL113:TPP) produced the best encapsulation of approximately 65%. Accelerated studies of the loaded NPs indicated stability under normal storage conditions (room temperature). Cytotoxicity assessment showed no significant loss of cell viability and in vitro ...