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Chen K, Sun M, Chen S. Determining ideal offsets of spatially offset Raman spectroscopy for transcutaneous measurements-A Monte Carlo study. JOURNAL OF BIOPHOTONICS 2024; 17:e202300564. [PMID: 38887978 DOI: 10.1002/jbio.202300564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/09/2024] [Accepted: 04/25/2024] [Indexed: 06/20/2024]
Abstract
Spatially offset Raman spectroscopy (SORS) is valuable for noninvasive bone assessment but requires a clearer understanding of how offset distances influence detection depth. To address this, our study devised a forward-adjoint Monte Carlo multi-layer (MCML) model to simulate photon paths in SORS, aiming to determine optimal offsets for various tissue types. We examined photon migration at offsets between 0 and 15 mm against layered phantoms of differing thicknesses and compositions to optimize the signal-to-noise ratio for bone layers. The findings highlight that optimal offsets are contingent on tissue characteristics: a metacarpal beneath 2.5 mm of tissue had an ideal offset of 6.7 mm, while a tibia with 5 mm of soft tissue required 10-11 mm. This precise calibration of SORS via MCML modeling promises substantial improvements in bone health diagnostics and potential for expansive medical applications.
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Affiliation(s)
- Keren Chen
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, China
- Foshan Graduate School of Innovation, Northeastern University, Foshan, China
| | - Mengya Sun
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, China
- Foshan Graduate School of Innovation, Northeastern University, Foshan, China
| | - Shuo Chen
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, China
- Key Laboratory of Intelligent Computing in Medical Image, Ministry of Education, Northeastern University, Shenyang, China
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2
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Vogiatzi A, Keklikoglou K, Makris K, Argyrou DS, Zacharopoulos A, Sotiropoulou V, Parthenios N, Gkikas A, Kokkori M, Richardson MSW, Fenwick AL, Archontidi S, Arvanitidis C, Robertson J, Parthenios J, Zacharakis G, Twigg SRF, Wilkie AOM, Mavrothalassitis G. Development of Erf-Mediated Craniosynostosis and Pharmacological Amelioration. Int J Mol Sci 2023; 24:7961. [PMID: 37175668 PMCID: PMC10178537 DOI: 10.3390/ijms24097961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/19/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
ETS2 repressor factor (ERF) insufficiency causes craniosynostosis (CRS4) in humans and mice. ERF is an ETS domain transcriptional repressor regulated by Erk1/2 phosphorylation via nucleo-cytoplasmic shuttling. Here, we analyze the onset and development of the craniosynostosis phenotype in an Erf-insufficient mouse model and evaluate the potential of the residual Erf activity augmented by pharmacological compounds to ameliorate the disease. Erf insufficiency appears to cause an initially compromised frontal bone formation and subsequent multisuture synostosis, reflecting distinct roles of Erf on the cells that give rise to skull and facial bones. We treated animals with Mek1/2 and nuclear export inhibitors, U0126 and KPT-330, respectively, to increase Erf activity by two independent pathways. We implemented both a low dosage locally over the calvaria and a systemic drug administration scheme to evaluate the possible indirect effects from other systems and minimize toxicity. The treatment of mice with either the inhibitors or the administration scheme alleviated the synostosis phenotype with minimal adverse effects. Our data suggest that the ERF level is an important regulator of cranial bone development and that pharmacological modulation of its activity may represent a valid intervention approach both in CRS4 and in other syndromic forms of craniosynostosis mediated by the FGFR-RAS-ERK-ERF pathway.
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Affiliation(s)
- Angeliki Vogiatzi
- Medical School, University of Crete, 71003 Heraklion, Crete, Greece
- IMBB, FORTH, 71003 Heraklion, Crete, Greece
| | - Kleoniki Keklikoglou
- Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), Hellenic Centre for Marine Research (HCMR), P.O. Box 2214, 71003 Heraklion, Crete, Greece
- Biology Department, University of Crete, 71003 Heraklion, Crete, Greece
| | | | | | | | | | | | - Angelos Gkikas
- Medical School, University of Crete, 71003 Heraklion, Crete, Greece
| | - Maria Kokkori
- Medical School, University of Crete, 71003 Heraklion, Crete, Greece
| | - Melodie S. W. Richardson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK
| | - Aimée L. Fenwick
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Sofia Archontidi
- Medical School, University of Crete, 71003 Heraklion, Crete, Greece
| | - Christos Arvanitidis
- Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), Hellenic Centre for Marine Research (HCMR), P.O. Box 2214, 71003 Heraklion, Crete, Greece
- LifeWatch ERIC, Sector II-II, Plaza de España, 41071 Seville, Spain
| | - Jeremy Robertson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK
| | | | | | - Stephen R. F. Twigg
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Andrew O. M. Wilkie
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - George Mavrothalassitis
- Medical School, University of Crete, 71003 Heraklion, Crete, Greece
- IMBB, FORTH, 71003 Heraklion, Crete, Greece
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3
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Querido W, Kandel S, Pleshko N. Applications of Vibrational Spectroscopy for Analysis of Connective Tissues. Molecules 2021; 26:922. [PMID: 33572384 PMCID: PMC7916244 DOI: 10.3390/molecules26040922] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/30/2021] [Accepted: 02/04/2021] [Indexed: 02/07/2023] Open
Abstract
Advances in vibrational spectroscopy have propelled new insights into the molecular composition and structure of biological tissues. In this review, we discuss common modalities and techniques of vibrational spectroscopy, and present key examples to illustrate how they have been applied to enrich the assessment of connective tissues. In particular, we focus on applications of Fourier transform infrared (FTIR), near infrared (NIR) and Raman spectroscopy to assess cartilage and bone properties. We present strengths and limitations of each approach and discuss how the combination of spectrometers with microscopes (hyperspectral imaging) and fiber optic probes have greatly advanced their biomedical applications. We show how these modalities may be used to evaluate virtually any type of sample (ex vivo, in situ or in vivo) and how "spectral fingerprints" can be interpreted to quantify outcomes related to tissue composition and quality. We highlight the unparalleled advantage of vibrational spectroscopy as a label-free and often nondestructive approach to assess properties of the extracellular matrix (ECM) associated with normal, developing, aging, pathological and treated tissues. We believe this review will assist readers not only in better understanding applications of FTIR, NIR and Raman spectroscopy, but also in implementing these approaches for their own research projects.
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Affiliation(s)
| | | | - Nancy Pleshko
- Department of Bioengineering, Temple University, Philadelphia, PA 19122, USA; (W.Q.); (S.K.)
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Sadyrin E, Swain M, Mitrin B, Rzhepakovsky I, Nikolaev A, Irkha V, Yogina D, Lyanguzov N, Maksyukov S, Aizikovich S. Characterization of Enamel and Dentine about a White Spot Lesion: Mechanical Properties, Mineral Density, Microstructure and Molecular Composition. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1889. [PMID: 32967152 PMCID: PMC7560001 DOI: 10.3390/nano10091889] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/10/2020] [Accepted: 09/17/2020] [Indexed: 11/17/2022]
Abstract
The study focuses on in vitro tracing of some fundamental changes that emerge in teeth at the initial stage of caries development using multiple approaches. The research was conducted on a mostly sound maxillary molar tooth but with a clearly visible natural proximal white spot lesion (WSL). Values of mineral density, reduced Young's modulus, indentation hardness and creep as well as the molecular composition and surface microstructure of the WSL and bordering dentine area were studied. The results obtained were compared to those of sound enamel and dentine on the same tooth. A decrease of mechanical properties and mineral density both for the WSL and bordering dentine was detected in comparison to the sound counterparts, as well as increase of creep for the enamel WSL. Differences in molecular composition and surface microstructure (including the indenter impressions) were found and described. WSL induces a serious change in the state of not only the visually affected enamel but also surrounding visually intact enamel and dentine in its vicinity. The results provide the basis for future studies of efficacy of minimal invasive treatments of caries.
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Affiliation(s)
- Evgeniy Sadyrin
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
| | - Michael Swain
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
- Biomaterials and Bioengineering department, Faculty of Dentistry, The University of Sydney, Camperdown, Sydney NSW 2006, Australia
| | - Boris Mitrin
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
| | - Igor Rzhepakovsky
- Institute of Life Sciences, North Caucasus Federal University, Pushkin Street 1, 355009 Stavropol, Russia;
| | - Andrey Nikolaev
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
| | - Vladimir Irkha
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
- Federal Research Centre The Southern Scientific Centre of the Russian Academy of The Sciences, Chehova Street 41, 344006 Rostov-on-Don, Russia
| | - Diana Yogina
- Department of dentistry, Rostov State Medical University, Nakhichevansky Lane 29, 344022 Rostov-on-Don, Russia; (D.Y.); (S.M.)
| | - Nikolay Lyanguzov
- Faculty of Physics, Southern Federal University, Bolshaya Sadovaya Street 105/42, 344090 Rostov-on-Don, Russia;
| | - Stanislav Maksyukov
- Department of dentistry, Rostov State Medical University, Nakhichevansky Lane 29, 344022 Rostov-on-Don, Russia; (D.Y.); (S.M.)
| | - Sergei Aizikovich
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
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5
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Vardaki MZ, Kourkoumelis N. Tissue Phantoms for Biomedical Applications in Raman Spectroscopy: A Review. Biomed Eng Comput Biol 2020; 11:1179597220948100. [PMID: 32884391 PMCID: PMC7440735 DOI: 10.1177/1179597220948100] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 07/16/2020] [Indexed: 12/26/2022] Open
Abstract
Raman spectroscopy is a group of analytical techniques, currently applied in several research fields, including clinical diagnostics. Tissue-mimicking optical phantoms have been established as an essential intermediate stage for medical applications with their employment from spectroscopic techniques to be constantly growing. This review outlines the types of tissue phantoms currently employed in different biomedical applications of Raman spectroscopy, focusing on their composition and optical properties. It is therefore an attempt to present an informed range of options for potential use to the researchers.
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Affiliation(s)
- Martha Z Vardaki
- Department of Medical Physics, School of Health Sciences, University of Ioannina, Ioannina, Greece
| | - Nikolaos Kourkoumelis
- Department of Medical Physics, School of Health Sciences, University of Ioannina, Ioannina, Greece
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Al-Rifai R, Tournois C, Kheirallah S, Bouland N, Poitevin G, Nguyen P, Beljebbar A. Subcutaneous and transcutaneous monitoring of murine hindlimb ischemia by in vivo Raman spectroscopy. Analyst 2019; 144:4677-4686. [PMID: 31268052 DOI: 10.1039/c8an02449a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have investigated the development of murine hindlimb ischemia from day 1 to day 55 after femoral artery ligation (FAL) using blood flow analysis, functional tests, histopathological staining, and in vivo Raman spectroscopy. FAL resulted in hindlimb blood deprivation and the loss of functionality as attested by the blood flow analysis and functional tests, respectively. The limbs recovered a normal circulation progressively without recovering complete functionality. Histological analysis showed changes in the morphology of muscle fibers with intense inflammation. From day 22 to day 55 post-ischemia, regeneration of the myofibers was observed. Raman spectroscopic results related to subcutaneous analysis made the identification of modification in the biochemical constituents of hindlimb muscles possible during disease progression. Ischemia was characterized by a quantitative increase in the lipid content and a decrease in the protein content. The lipid to protein ratio can be used as a spectroscopic marker to score the severity of ischemia. Multivariate statistical analysis PC-LDA (Principal Component-Linear Discriminant Analysis) was used to classify all the data measured for the normal and ischemic tissues. This classification illustrated an excellent separation between the control and ischemic tissues at any time during the course of ischemic development. In vivo Raman spectroscopy was then applied to assess the potential of this technique as a screening tool to explore an ischemic disease non-invasively (transcutaneously). For this purpose, the influence of skin on the diagnostic accuracy was evaluated; transcutaneous analysis revealed the accuracy of this technique, indicating its potential in the in situ monitoring of muscle structural changes during ischemia.
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Affiliation(s)
- Rida Al-Rifai
- EA 3801, SFR CAP-Santé, Université de Reims Champagne-Ardenne, France
| | - Claire Tournois
- EA 3801, SFR CAP-Santé, Université de Reims Champagne-Ardenne, France and Laboratoire d'Hématologie, CHU Robert Debré, Reims, France
| | | | - Nicole Bouland
- Laboratoire d'Anatomopathologie, Université de Reims Champagne-Ardenne, France
| | - Gaël Poitevin
- EA 3801, SFR CAP-Santé, Université de Reims Champagne-Ardenne, France
| | - Philippe Nguyen
- EA 3801, SFR CAP-Santé, Université de Reims Champagne-Ardenne, France and Laboratoire d'Hématologie, CHU Robert Debré, Reims, France
| | - Abdelilah Beljebbar
- BioSpectroscopie Translationnelle BioSpecT, EA 7506, Université de Reims Champagne-Ardenne, France.
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Dooley M, Prasopthum A, Liao Z, Sinjab F, McLaren J, Rose FRAJ, Yang J, Notingher I. Spatially-offset Raman spectroscopy for monitoring mineralization of bone tissue engineering scaffolds: feasibility study based on phantom samples. BIOMEDICAL OPTICS EXPRESS 2019; 10:1678-1690. [PMID: 31061762 PMCID: PMC6484990 DOI: 10.1364/boe.10.001678] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/01/2019] [Accepted: 02/06/2019] [Indexed: 05/21/2023]
Abstract
Using phantom samples, we investigated the feasibility of spatially-offset Raman spectroscopy (SORS) as a tool for monitoring non-invasively the mineralization of bone tissue engineering scaffold in-vivo. The phantom samples consisted of 3D-printed scaffolds of poly-caprolactone (PCL) and hydroxyapatite (HA) blends, with varying concentrations of HA, to mimic the mineralisation process. The scaffolds were covered by a 4 mm layer of skin to simulate the real in-vivo measurement conditions. At a concentration of HA approximately 1/3 that of bone (~0.6 g/cm3), the characteristic Raman band of HA (960 cm-1) was detectable when the PCL:HA layer was located at 4 mm depth within the scaffold (i.e. 8 mm below the skin surface). For the layers of the PCL:HA immediately under the skin (i.e. top of the scaffold), the detection limit of HA was 0.18 g/cm3, which is approximately one order of magnitude lower than that of bone. Similar results were also found for the phantoms simulating uniform and inward gradual mineralisation of the scaffold, indicating the suitability of SORS to detect early stages of mineralisation. Nevertheless, the results also show that the contribution of the materials surrounding the scaffold can be significant and methods for subtraction need to be investigated in the future. In conclusion, these results indicate that spatially-offset Raman spectroscopy is a promising technique for in-vivo longitudinal monitoring scaffold mineralization and bone re-growth.
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Affiliation(s)
- Max Dooley
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Aruna Prasopthum
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Zhiyu Liao
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Faris Sinjab
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Jane McLaren
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | | | - Jing Yang
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Ioan Notingher
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Akkus A, Yang S, Roperto R, Mustafa H, Teich S, Akkus O. A portable fiber-optic raman spectrometer concept for evaluation of mineral content within enamel tissue. J Clin Exp Dent 2017; 9:e238-e241. [PMID: 28210442 PMCID: PMC5303324 DOI: 10.4317/jced.53185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/08/2016] [Indexed: 11/24/2022] Open
Abstract
Background Measurement of tooth enamel mineralization using a clinically viable method is essential since variation of mineralization may be used to monitor caries risk or in assessing the effectiveness of remineralization therapy. Fiber optic Raman systems are becoming more affordable and popular in context of biomedical applications. However, the applicability of fiber optic Raman systems for measurement of mineral content within enamel tissue has not been elucidated significantly in the prior literature. Material and Methods Human teeth with varying degrees of enamel mineralization were selected. In addition alligator, boar and buffalo teeth which have increasing amount of mineral content, respectively, were also included as another set of samples. Reference Raman measurements of mineralization were performed using a high-fidelity confocal Raman microscope. Results Analysis of human teeth by research grade Raman system indicated a 2-fold difference in the Raman intensities of v1 symmetric-stretch bands of mineral-related phosphate bonds and 7-fold increase in mineral related Raman intensities of animal teeth. However, fiber optic system failed to resolve the differences in the mineralization of human teeth. Conclusions These results indicate that the sampling volume of fiber optic systems extends to the underlying dentin and that confocal aperture modification is essential to limit the sampling volume to within the enamel. Further research efforts will focus on putting together portable Raman systems integrated with confocal fiber probe. Key words:Enamel, mineral content, raman spectroscopy.
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Affiliation(s)
- Anna Akkus
- PhD, CWRU School of Dental Medicine, 2124 Cornell Road, Cleveland, OH 44106-4905
| | - Shan Yang
- PhD, Jackson State University, Department of Physics, Atmospheric Science and Geophysics, 1400 John R. Lynch St Jackson, MS 39217
| | - Renato Roperto
- DDS, MSc, PhD, CWRU School of Dental Medicine, 2124 Cornell Road, Cleveland, OH 44106-4905
| | - Hathem Mustafa
- PhD, Department of Mechanical and Aerospace Engineering, Case Western Reserve University, 10900 Euclid Ave.Cleveland, Ohio 44106-7222
| | - Sorin Teich
- DDS, MBA, CWRU School of Dental Medicine, 2124 Cornell Road, Cleveland, OH 44106-4905
| | - Ozan Akkus
- PhD, Department of Mechanical and Aerospace Engineering, Case Western Reserve University, 10900 Euclid Ave.Cleveland, Ohio 44106-7222
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Akkus A, Akkus A, Roperto R, Akkus O, Porto T, Teich S, Lang L. Evaluation of mineral content in healthy permanent human enamel by Raman spectroscopy. J Clin Exp Dent 2016; 8:e546-e549. [PMID: 27957268 PMCID: PMC5149089 DOI: 10.4317/jced.53057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/16/2016] [Indexed: 11/30/2022] Open
Abstract
Background An understanding of tooth enamel mineral content using a clinically viable method is essential since variations in mineralization may serve as an early precursor of a dental health issues, and may predict progression and architecture of decay in addition to assessing the success and effectiveness of the remineralization strategies. Material and Methods Twenty two human incisor teeth were obtained in compliance with the NIH guidelines and site specifically imaged with Raman microscope. The front portion of the teeth was divided into apical, medium and cervical regions and subsequently imaged with Raman microscope in these three locations. Results Measured mineralization levels have varied substantially depending on the regions. It was also observed that, the cervical enamel is the least mineralization as a populational average. Conclusions Enamel mineralization is affected by a many factors such as are poor oral hygiene, alcohol consumption and high intake of dietary carbohydrates, however the net effect manifests as overall mineral content of the enamel. Thus an early identification of the individual with overall low mineral content of the enamel may be a valuable screening tool in determining a group with much higher than average caries risk, allowing intervention before development of caries. Clinically applicable non-invasive techniques that can quantify mineral content, such as Raman analysis, would help answer whether or not mineralization is associated with caries risk. Key words:Enamel, Raman spectroscopy, mineral content, dental caries.
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Affiliation(s)
- Anna Akkus
- PhD, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Asya Akkus
- Case Biomanufacturing and Microfabrication Laboratory, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Renato Roperto
- DDS, MSc, PhD, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ozan Akkus
- PhD, Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Thiago Porto
- PhD, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; DDS, MSc, PhD, Department of Restorative Dentistry, Faculty of Dentistry, Sao Paulo State University, Araraquara, SP, Brazil
| | - Sorin Teich
- DDS, MBA, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Lisa Lang
- DDS, MBA, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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10
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Stevens O, Iping Petterson IE, Day JCC, Stone N. Developing fibre optic Raman probes for applications in clinical spectroscopy. Chem Soc Rev 2016; 45:1919-34. [PMID: 26956027 DOI: 10.1039/c5cs00850f] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Raman spectroscopy has been shown by various groups over the last two decades to have significant capability in discriminating disease states in bodily fluids, cells and tissues. Recent development in instrumentation, optics and manufacturing approaches has facilitated the design and demonstration of various novel in vivo probes, which have applicability for myriad of applications. This review focusses on key considerations and recommendations for application specific clinical Raman probe design and construction. Raman probes can be utilised as clinical tools able to provide rapid, non-invasive, real-time molecular analysis of disease specific changes in tissues. Clearly the target tissue location, the significance of spectral changes with disease and the possible access routes to the region of interest will vary for each clinical application considered. This review provides insight into design and construction considerations, including suitable probe designs and manufacturing materials compatible with Raman spectroscopy.
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Affiliation(s)
- Oliver Stevens
- Biomedical Physics, School of Physics and Astronomy, University of Exeter, Exeter, Devon EX4 4QL, UK.
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11
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Matousek P, Stone N. Development of deep subsurface Raman spectroscopy for medical diagnosis and disease monitoring. Chem Soc Rev 2016; 45:1794-802. [DOI: 10.1039/c5cs00466g] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The advent of non-invasive deep Raman techniques heralds the emergence of novel diagnostic and disease monitoring methods.
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Affiliation(s)
- Pavel Matousek
- Central Laser Facility
- Research Complex at Harwell
- STFC Rutherford Appleton Laboratory
- Harwell Oxford
- UK
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12
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Gong B, Morris MD. Raman spectroscopy monitors adverse bone sequelae of cancer radiotherapy. CHINESE CHEM LETT 2015. [DOI: 10.1016/j.cclet.2014.11.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Demers JLH, Esmonde-White FW, Esmonde-White KA, Morris MD, Pogue BW. Next-generation Raman tomography instrument for non-invasive in vivo bone imaging. BIOMEDICAL OPTICS EXPRESS 2015; 6:793-806. [PMID: 25798304 PMCID: PMC4361434 DOI: 10.1364/boe.6.000793] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/15/2015] [Accepted: 01/15/2015] [Indexed: 05/20/2023]
Abstract
Combining diffuse optical tomography methods with Raman spectroscopy of tissue provides the ability for in vivo measurements of chemical and molecular characteristics, which have the potential for being useful in diagnostic imaging. In this study a system for Raman tomography was developed and tested. A third generation microCT coupled system was developed to combine 10 detection fibers and 5 excitation fibers with laser line filtering and a Cytop reference signal. Phantom measurements of hydroxyapatite concentrations from 50 to 300 mg/ml had a linear response. Fiber placement and experiment design was optimized using cadaver animals with live animal measurements acquired to validate the systems capabilities. Promising results from the initial animal experiments presented here, pave the way for a study of longitudinal measurements during fracture healing and the scaling of the Raman tomography system towards human measurements.
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Affiliation(s)
- Jennifer-Lynn H. Demers
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, 03755,
USA
- JLHD and FEW have made equal contributions to the manuscript
| | - Francis W.L. Esmonde-White
- University of Michigan, Department of Chemistry, Ann Arbor, Michigan, 48109,
USA
- Current affiliation: Kaiser Optical Systems, Inc, Ann Arbor Michigan, 48103,
USA
- JLHD and FEW have made equal contributions to the manuscript
| | - Karen A. Esmonde-White
- University of Michigan Medical School, Department of Internal Medicine-Division of Rheumatology, Ann Arbor, Michigan, 48109,
USA
| | - Michael D. Morris
- University of Michigan, Department of Chemistry, Ann Arbor, Michigan, 48109,
USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, 03755,
USA
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Gamsjaeger S, Mendelsohn R, Boskey AL, Gourion-Arsiquaud S, Klaushofer K, Paschalis EP. Vibrational spectroscopic imaging for the evaluation of matrix and mineral chemistry. Curr Osteoporos Rep 2014; 12:454-64. [PMID: 25240579 PMCID: PMC4638121 DOI: 10.1007/s11914-014-0238-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Metabolic bone diseases manifesting fragility fractures (such as osteoporosis) are routinely diagnosed based on bone mineral density (BMD) measurements, and the effect of various therapies also evaluated based on the same outcome. Although useful, it is well recognized that this metric does not fully account for either fracture incidence or the effect of various therapies on fracture incidence, thus, the emergence of bone quality as a contributing factor in the determination of bone strength. Infrared and Raman vibrational spectroscopic techniques are particularly well-suited for the determination of bone quality as they provide quantitative and qualitative information of the mineral and organic matrix bone components, simultaneously. Through the use of microspectroscopic techniques, this information is available in a spatially resolved manner, thus, the outcomes may be easily correlated with outcomes from techniques such as histology, histomorphometry, and nanoindentation, linking metabolic status with material properties.
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Affiliation(s)
- S. Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital, of WGKK and AUVA Trauma Centre Meidling, 1st Medical, Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | | | | | | | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital, of WGKK and AUVA Trauma Centre Meidling, 1st Medical, Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - E. P. Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital, of WGKK and AUVA Trauma Centre Meidling, 1st Medical, Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria,
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15
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Tandon R, Herford AS. The case for advanced physics topics in oral and maxillofacial surgery. J Oral Maxillofac Surg 2014; 72:1876-9. [PMID: 25234523 DOI: 10.1016/j.joms.2014.06.441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 06/13/2014] [Accepted: 06/17/2014] [Indexed: 11/25/2022]
Abstract
Research in oral and maxillofacial surgery has focused mainly on principles founded in the biological and chemical sciences, which have provided excellent answers to many questions. However, recent technologic advances have begun to gain prominence in many of the medical sciences, providing clinicians with more effective tools for diagnosis and treatment. The era of modern physics has led to the development of diagnostic techniques that could provide information at a more basic level than many of the current biochemical methods used. The goal of this report is to introduce 2 of these methods and describe how they can be applied to oral and maxillofacial surgery.
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Affiliation(s)
- Rahul Tandon
- Resident, Department of Oral and Maxillofacial Surgery, University of Texas Southwestern, Dallas, TX.
| | - Alan S Herford
- Chairman, Department of Oral and Maxillofacial Surgery, Loma Linda University, Loma Linda, CA
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16
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Gong B, Oest ME, Mann KA, Damron TA, Morris MD. Raman spectroscopy demonstrates prolonged alteration of bone chemical composition following extremity localized irradiation. Bone 2013; 57:252-8. [PMID: 23978492 PMCID: PMC3789379 DOI: 10.1016/j.bone.2013.08.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Radiotherapy to the appendicular skeleton can cause an increased risk of developing catastrophic fractures with delayed bone healing or non-union, and may subsequently require multiple procedures and amputation. Biomechanical studies suggest that irradiated bone is more brittle, but the cause is unclear and cannot be explained by changes to bone structure or quantity, suggesting that there are crucial changes in irradiated bone material properties. Raman spectroscopy provides a means to assess the chemical properties of the mineral and matrix constituents of bone, which could help explain post-radiation embrittlement. In this study we use a murine tibial model with focal irradiation and perform Raman spectroscopy to test the hypothesis that changes in bone chemistry following irradiation is consistent with reduced bone quality and persists in the long term after irradiation. METHODS Female BALB/F mice aged 12weeks were subjected to unilateral, localized hindlimb irradiation in 4 daily 5Gy fractions (4×5Gy) totaling 20Gy, and were euthanized at 1, 4, 8, 12, and 26weeks post-irradiation (n=6/group). The irradiated (right) and non-irradiated contralateral control (left) tibiae were explanted and assessed by non-polarized and polarized Raman spectroscopy over the proximal cortical bone surface. Raman parameters used included the mineral/matrix ratio, mineral crystallinity, carbonate/phosphate ratio, collagen cross-link ratio, and depolarization ratio. RESULTS Significantly increased collagen cross-link ratio and decreased depolarization ratio of matrix were evident at 1week after irradiation and this persisted through 26weeks. A similar significant decrease was observed for depolarization ratio of mineral at all time points except 8 and 26weeks. At 4weeks after irradiation there was a significantly increased mineral/matrix ratio, increased mineral crystallinity, and decreased carbonate/phosphate ratio compared to controls. However, at 12weeks after irradiation these parameters had moved in the opposite direction, resulting in a significantly decreased mineral/matrix ratio, decreased crystallinity and increased carbonate/phosphate ratio compared to controls. At 26weeks, mineral/matrix, crystallinity and carbonate/phosphate ratios had returned to normal. DISCUSSION In this mouse model, Raman spectroscopy reports both bone mineral and collagen cross-link radiation-induced abnormalities that are evident as early as one week after irradiation and persists for 26weeks. The picture is one of extensive damage, after which there is an attempt at remodeling. We hypothesize that pathological cross-links formed by radiation damage to collagen are poorly resorbed during the altered remodeling process, so that new tissue is formed on a defective scaffold, resulting in increased bone brittleness.
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Affiliation(s)
- Bo Gong
- Department of Chemistry; University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan E. Oest
- Department of Orthopedic Surgery, Upstate Medical University, Syracuse, NY 13210, USA
| | - Kenneth A. Mann
- Department of Orthopedic Surgery, Upstate Medical University, Syracuse, NY 13210, USA
| | - Timothy A. Damron
- Department of Orthopedic Surgery, Upstate Medical University, Syracuse, NY 13210, USA
| | - Michael D. Morris
- Department of Chemistry; University of Michigan, Ann Arbor, MI 48109, USA
- Corresponding author at: Department of Chemistry, University of Michigan, 930, N. University Avenue, Room 4811, Ann Arbor, MI 48109-1055, USA. Fax: +1 734 764 7360. (M.D.Morris)
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17
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Maher JR, Inzana JA, Awad HA, Berger AJ. Overconstrained library-based fitting method reveals age- and disease-related differences in transcutaneous Raman spectra of murine bones. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:077001. [PMID: 23817761 PMCID: PMC3697032 DOI: 10.1117/1.jbo.18.7.077001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Clinical diagnoses of bone health and fracture risk typically rely on measurements of bone density or structure, but the strength of a bone is also dependent on its chemical composition. Raman spectroscopy has been used extensively in ex vivo studies to measure the chemical composition of bone. Recently, spatially offset Raman spectroscopy (SORS) has been utilized to measure bone transcutaneously. Although the results are promising, further advancements are necessary to make noninvasive, in vivo measurements of bone with SORS that are of sufficient quality to generate accurate predictions of fracture risk. In order to separate the signals from bone and soft tissue that contribute to a transcutaneous measurement, we developed an overconstrained extraction algorithm that is based on fitting with spectral libraries. This approach allows for accurate spectral unmixing despite the fact that similar chemical components (e.g., type I collagen) are present in both bone and soft tissue. The algorithm was utilized to transcutaneously detect biochemical differences in the tibiae of wild-type mice between 1 and 7 months of age and between the tibiae of wild-type mice and a mouse model of osteogenesis imperfecta. These results represent the first diagnostically sensitive, transcutaneous measurements of bone using SORS.
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Affiliation(s)
- Jason R Maher
- The Institute of Optics, University of Rochester, 275 Hutchison Road, Rochester, New York 14627, USA
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18
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Ellis DI, Cowcher DP, Ashton L, O'Hagan S, Goodacre R. Illuminating disease and enlightening biomedicine: Raman spectroscopy as a diagnostic tool. Analyst 2013; 138:3871-84. [PMID: 23722248 DOI: 10.1039/c3an00698k] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The discovery of the Raman effect in 1928 not only aided fundamental understanding about the quantum nature of light and matter but also opened up a completely novel area of optics and spectroscopic research that is accelerating at a greater rate during the last decade than at any time since its inception. This introductory overview focuses on some of the most recent developments within this exciting field and how this has enabled and enhanced disease diagnosis and biomedical applications. We highlight a small number of stimulating high-impact studies in imaging, endoscopy, stem cell research, and other recent developments such as spatially offset Raman scattering amongst others. We hope this stimulates further interest in this already exciting field, by 'illuminating' some of the current research being undertaken by the latest in a very long line of dedicated experimentalists interested in the properties and potential beneficial applications of light.
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Affiliation(s)
- David I Ellis
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7ND, UK.
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19
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Shin K, Chung H. Wide area coverage Raman spectroscopy for reliable quantitative analysis and its applications. Analyst 2013; 138:3335-46. [PMID: 23636144 DOI: 10.1039/c3an36843b] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review summarizes recent studies to improve sample representation in Raman measurement by covering a large area of a sample in spectral collection. Three different schemes have been mainly investigated to fulfill the goal: (1) averaging of Raman spectra collected at many different locations on a sample, (2) rotation of a sample during spectral collection and (3) simultaneous wide area illumination (WAI) for spectral collection. The use of a wide area illumination scheme, simultaneously illuminating a laser over a large area for spectral acquisition without any further assistance such as sample rotation, has increased in diverse fields. Applications employing the WAI scheme in pharmaceutical, polymer/chemical/petrochemical and other areas are described in this review.
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Affiliation(s)
- Kayeong Shin
- Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 133-791, Korea
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20
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Microchemical investigation of bone derived from mice treated with strontium in different chemical forms using scanning electron microscopy and micro-Raman spectroscopy. Microchem J 2013. [DOI: 10.1016/j.microc.2012.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Tchanque-Fossuo CN, Gong B, Poushanchi B, Donneys A, Sarhaddi D, Gallagher KK, Deshpande SS, Goldstein SA, Morris MD, Buchman SR. Raman spectroscopy demonstrates Amifostine induced preservation of bone mineralization patterns in the irradiated murine mandible. Bone 2013; 52:712-717. [PMID: 22885239 PMCID: PMC3789510 DOI: 10.1016/j.bone.2012.07.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 07/26/2012] [Accepted: 07/27/2012] [Indexed: 12/28/2022]
Abstract
PURPOSE Adjuvant radiotherapy in the management of head and neck cancer remains severely debilitating. Fortunately, newly developed agents aimed at decreasing radiation-induced damage have shown great promise. Amifostine (AMF) is a compound, which confers radio-protection to the exposed normal tissues, such as bone. Our intent is to utilize Raman spectroscopy to demonstrate how AMF preserves the mineral composition of the murine mandible following human equivalent radiation. METHODS Sprague Dawley rats were randomized into 3 experimental groups: control (n=5), XRT (n=5), and AMF-XRT (n=5). Both XRT and AMF groups underwent bioequivalent radiation of 70Gy in 5 fractions to the left hemimandible. AMF-XRT received Amifostine prior to radiation. Fifty-six days post-radiation, the hemimandibles were harvested, and Raman spectra were taken in the region of interest spanning 2mm behind the last molar. Bone mineral and matrix-specific Raman bands were analyzed using one-way ANOVA, with statistical significance at p<0.05. RESULTS The full-width at half-maximum of the primary phosphate band (FWHM) and the ratio of carbonate/phosphate intensities demonstrated significant differences between AMF-XRT versus XRT (p<0.01) and XRT versus control (p<0.01). There was no difference between AMF-XRT and control (p>0.05) in both Raman metrics. Computer-aided spectral subtraction further confirmed these results where AMF-XRT was spectrally similar to the control. Interestingly, the collagen cross-link ratio did not differ between XRT and AMF-XRT (p<0.01) but was significantly different from the control (p<0.01). CONCLUSION Our novel findings demonstrate that AMF prophylaxis maintains and protects bone mineral quality in the setting of radiation. Raman spectroscopy is an emerging and exceptionally attractive clinical translational technology to investigate and monitor both the destructive effects of radiation and the therapeutic remediation of AMF on the structural, physical and chemical qualities of bone.
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Affiliation(s)
- Catherine N. Tchanque-Fossuo
- University of Michigan Hospital and Health Systems, Pediatric Plastic Surgery Section, 1540 E. Hospital Drive, MI 48109, USA
| | - Bo Gong
- University of Michigan Hospital and Health Systems, Department of Chemistry, 930 N. University, Ann Arbor, MI 48109, USA
| | - Behdod Poushanchi
- University of Michigan Hospital and Health Systems, Pediatric Plastic Surgery Section, 1540 E. Hospital Drive, MI 48109, USA
| | - Alexis Donneys
- University of Michigan Hospital and Health Systems, Pediatric Plastic Surgery Section, 1540 E. Hospital Drive, MI 48109, USA
| | - Deniz Sarhaddi
- University of Michigan Hospital and Health Systems, Pediatric Plastic Surgery Section, 1540 E. Hospital Drive, MI 48109, USA
| | - K. Kelly Gallagher
- University of Michigan Hospital and Health Systems, Department of Otolaryngology–Head and Neck Surgery, University of Michigan Medical School, 1500 E. Medical Center Drive, Ann Arbor, MI 48109, USA
| | - Sagar S. Deshpande
- University of Michigan Hospital and Health Systems, Pediatric Plastic Surgery Section, 1540 E. Hospital Drive, MI 48109, USA
| | - Steven A. Goldstein
- University of Michigan, Department of Orthopaedic Surgery, A. Alfred Taubman Biomedical Science Research Building, 109 Zina Pitcher Pl, Ann Arbor, MI, 48109, USA
| | - Michael D. Morris
- University of Michigan Hospital and Health Systems, Department of Chemistry, 930 N. University, Ann Arbor, MI 48109, USA
| | - Steven R. Buchman
- University of Michigan Hospital and Health Systems, Pediatric Plastic Surgery Section, 1540 E. Hospital Drive, MI 48109, USA
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22
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Matousek P, Stone N. Recent advances in the development of Raman spectroscopy for deep non-invasive medical diagnosis. JOURNAL OF BIOPHOTONICS 2013; 6:7-19. [PMID: 23129567 DOI: 10.1002/jbio.201200141] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/13/2012] [Accepted: 09/18/2012] [Indexed: 05/21/2023]
Abstract
Raman spectroscopy has recently undergone major advances in the area of deep non-invasive characterisation of biological tissues. The progress stems from the development of spatially offset Raman spectroscopy (SORS) and renaissance of transmission Raman spectroscopy permitting the assessment of diffusely scattering samples at depths several orders of magnitude deeper than possible with conventional Raman spectroscopy. Examples of emerging applications include non-invasive diagnosis of bone disease, cancer and monitoring of glucose levels. This article reviews this fast moving field focusing on recent developments within the medical area.
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Affiliation(s)
- Pavel Matousek
- Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Harwell Oxford, UK.
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23
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Tandon R, Herford A. Poster 67: Using Raman Spectroscopy To Evaluate Bone Graft and Implant Osseointegration Non-Invasively: A Novel and Groundbreaking Technique. J Oral Maxillofac Surg 2012. [DOI: 10.1016/j.joms.2012.06.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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Okagbare PI, Begun D, Tecklenburg M, Awonusi A, Goldstein SA, Morris MD. Noninvasive Raman spectroscopy of rat tibiae: approach to in vivo assessment of bone quality. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:90502-1. [PMID: 23085899 PMCID: PMC3434704 DOI: 10.1117/1.jbo.17.9.090502] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/29/2012] [Accepted: 07/31/2012] [Indexed: 05/18/2023]
Abstract
We report on in vivo noninvasive Raman spectroscopy of rat tibiae using robust fiber-optic Raman probes and holders designed for transcutaneous Raman measurements in small animals. The configuration allows placement of multiple fibers around a rat leg, maintaining contact with the skin. Bone Raman data are presented for three regions of the rat tibia diaphysis with different thicknesses of overlying soft tissue. The ability to perform in vivo noninvasive Raman measurement and evaluation of subtle changes in bone composition is demonstrated with rat leg phantoms in which the tibia has carbonated hydroxylapatite, with different carbonate contents. Our data provide proof of the principle that small changes in bone composition can be monitored through soft tissue at anatomical sites of interest in biomedical studies.
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Affiliation(s)
- Paul I. Okagbare
- University of Michigan, Department of Chemistry, Ann Arbor, Michigan
| | - Dana Begun
- University of Michigan, Medical School, Orthopedic Research Laboratories, Department of Orthopedic Surgery, Ann Arbor, Michigan
| | - Mary Tecklenburg
- Central Michigan University, Department of Chemistry, Mt. Pleasant, Michigan
| | - Ayorinde Awonusi
- Central Michigan University, Department of Chemistry, Mt. Pleasant, Michigan
| | - Steven A. Goldstein
- University of Michigan, Medical School, Orthopedic Research Laboratories, Department of Orthopedic Surgery, Ann Arbor, Michigan
| | - Michael D. Morris
- University of Michigan, Department of Chemistry, Ann Arbor, Michigan
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25
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OKAGBARE PAULI, MORRIS MICHAELD. Fluorocarbon fiber-optic Raman probe for non-invasive Raman spectroscopy. APPLIED SPECTROSCOPY 2012; 66:728-30. [PMID: 22732546 PMCID: PMC3384561 DOI: 10.1366/12-06592] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report the development of a novel fiber-optic Raman probe using a graded index fluorocarbon optical fiber. The fluorocarbon fiber has a simple Raman spectrum, a low fluorescence background, and generates a Raman signal that in turbid media serves as an intense reference Raman signal that corrects for albedo. The intensity of the reference signal can easily be varied as needed by scaling the length of the excitation fiber. Additionally, the fluorocarbon probe eliminates the broad silica Raman bands generated in conventional silica-core fiber without the need for filters.
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26
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Okagbare PI, Morris MD. Polymer-capped fiber-optic Raman probe for non-invasive Raman spectroscopy. Analyst 2011; 137:77-81. [PMID: 22059232 DOI: 10.1039/c1an15847c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Advances in fiber optic probe design are moving Raman spectroscopy into the clinic, although there remain important practical problems. While much effort has been devoted to minimizing Raman and fluorescence background from fibers, less attention has been given to the need to generate reference Raman signals that can correct for variations in tissue albedo, which is important in quantifying changes in tissue composition. To address this shortcoming, we have developed a fiber optic probe that incorporates a fluorinated ethylene-propylene copolymer (FEP) cap at the end of each excitation fiber. Transmission of laser light through the transparent cap generates a 732 cm(-1) Raman band whose intensity scales linearly with the laser power delivered to the tissue of interest. In our first design, the FEP cap functions as a waveguide with only a small insertion loss (~5%). Laser transmission through 1 mm of the polymer is sufficient to generate a usable reference Raman signal. We show the application of the probe to quantitative non-invasive Raman spectroscopy of animal tissues using rat leg phantoms as models. Ex-vivo Raman spectroscopy of excised rat tibia supports the use of the probe for spectroscopy of various tissues. These results provide proof of principle that the Raman probe can be used in multiple spectroscopic applications.
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Affiliation(s)
- Paul I Okagbare
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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