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Dong P, Stellmacher J, Bouchet LM, Nieke M, Kumar A, Osorio‐Blanco ER, Nagel G, Lohan SB, Teutloff C, Patzelt A, Schäfer‐Korting M, Calderón M, Meinke MC, Alexiev U. A Dual Fluorescence–Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM–EPR Spectroscopy. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202012852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Pin Dong
- Department of Dermatology, Venereology and Allergology Charité Universitätsmedizin Berlin corporate member of Freie Universität Berlin Humboldt-Universität zu Berlin, and Berlin Institute of Health Berlin Germany
- Freie Universität Berlin Institute of Pharmacy Berlin Germany
| | - Johannes Stellmacher
- Freie Universität Berlin Institute of Experimental Physics Department of Physics Berlin Germany
| | - Lydia M. Bouchet
- Freie Universität Berlin Institute of Chemistry and Biochemistry Berlin Germany
| | - Marius Nieke
- Freie Universität Berlin Institute of Experimental Physics Department of Physics Berlin Germany
- Humboldt-Universität zu Berlin Institute of Biology Berlin Germany
| | - Amit Kumar
- Freie Universität Berlin Institute of Chemistry and Biochemistry Berlin Germany
| | | | - Gregor Nagel
- Freie Universität Berlin Institute of Chemistry and Biochemistry Berlin Germany
| | - Silke B. Lohan
- Department of Dermatology, Venereology and Allergology Charité Universitätsmedizin Berlin corporate member of Freie Universität Berlin Humboldt-Universität zu Berlin, and Berlin Institute of Health Berlin Germany
| | - Christian Teutloff
- Freie Universität Berlin Institute of Experimental Physics Department of Physics Berlin Germany
| | - Alexa Patzelt
- Department of Dermatology, Venereology and Allergology Charité Universitätsmedizin Berlin corporate member of Freie Universität Berlin Humboldt-Universität zu Berlin, and Berlin Institute of Health Berlin Germany
| | | | - Marcelo Calderón
- Freie Universität Berlin Institute of Chemistry and Biochemistry Berlin Germany
- POLYMAT Faculty of Chemistry University of the Basque Country UPV/EHU 20018 Donostia-San Sebastián Spain
- IKERBASQUE Basque Foundation for Science 48013 Bilbao Spain
| | - Martina C. Meinke
- Department of Dermatology, Venereology and Allergology Charité Universitätsmedizin Berlin corporate member of Freie Universität Berlin Humboldt-Universität zu Berlin, and Berlin Institute of Health Berlin Germany
| | - Ulrike Alexiev
- Freie Universität Berlin Institute of Experimental Physics Department of Physics Berlin Germany
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2
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Dong P, Stellmacher J, Bouchet LM, Nieke M, Kumar A, Osorio‐Blanco ER, Nagel G, Lohan SB, Teutloff C, Patzelt A, Schäfer‐Korting M, Calderón M, Meinke MC, Alexiev U. A Dual Fluorescence-Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM-EPR Spectroscopy. Angew Chem Int Ed Engl 2021; 60:14938-14944. [PMID: 33544452 PMCID: PMC8251738 DOI: 10.1002/anie.202012852] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/27/2021] [Indexed: 12/30/2022]
Abstract
Simultaneous visualization and concentration quantification of molecules in biological tissue is an important though challenging goal. The advantages of fluorescence lifetime imaging microscopy (FLIM) for visualization, and electron paramagnetic resonance (EPR) spectroscopy for quantification are complementary. Their combination in a multiplexed approach promises a successful but ambitious strategy because of spin label-mediated fluorescence quenching. Here, we solved this problem and present the molecular design of a dual label (DL) compound comprising a highly fluorescent dye together with an EPR spin probe, which also renders the fluorescence lifetime to be concentration sensitive. The DL can easily be coupled to the biomolecule of choice, enabling in vivo and in vitro applications. This novel approach paves the way for elegant studies ranging from fundamental biological investigations to preclinical drug research, as shown in proof-of-principle penetration experiments in human skin ex vivo.
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Affiliation(s)
- Pin Dong
- Department of Dermatology, Venereology and AllergologyCharité Universitätsmedizin Berlincorporate member of Freie Universität BerlinHumboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
- Freie Universität BerlinInstitute of PharmacyBerlinGermany
| | - Johannes Stellmacher
- Freie Universität BerlinInstitute of Experimental PhysicsDepartment of PhysicsBerlinGermany
| | - Lydia M. Bouchet
- Freie Universität BerlinInstitute of Chemistry and BiochemistryBerlinGermany
| | - Marius Nieke
- Freie Universität BerlinInstitute of Experimental PhysicsDepartment of PhysicsBerlinGermany
- Humboldt-Universität zu BerlinInstitute of BiologyBerlinGermany
| | - Amit Kumar
- Freie Universität BerlinInstitute of Chemistry and BiochemistryBerlinGermany
| | | | - Gregor Nagel
- Freie Universität BerlinInstitute of Chemistry and BiochemistryBerlinGermany
| | - Silke B. Lohan
- Department of Dermatology, Venereology and AllergologyCharité Universitätsmedizin Berlincorporate member of Freie Universität BerlinHumboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Christian Teutloff
- Freie Universität BerlinInstitute of Experimental PhysicsDepartment of PhysicsBerlinGermany
| | - Alexa Patzelt
- Department of Dermatology, Venereology and AllergologyCharité Universitätsmedizin Berlincorporate member of Freie Universität BerlinHumboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | | | - Marcelo Calderón
- Freie Universität BerlinInstitute of Chemistry and BiochemistryBerlinGermany
- POLYMATFaculty of ChemistryUniversity of the Basque CountryUPV/EHU20018Donostia-San SebastiánSpain
- IKERBASQUEBasque Foundation for Science48013BilbaoSpain
| | - Martina C. Meinke
- Department of Dermatology, Venereology and AllergologyCharité Universitätsmedizin Berlincorporate member of Freie Universität BerlinHumboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Ulrike Alexiev
- Freie Universität BerlinInstitute of Experimental PhysicsDepartment of PhysicsBerlinGermany
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Moore T, Chen H, Morrison R, Wang F, Anker JN, Alexis F. Nanotechnologies for noninvasive measurement of drug release. Mol Pharm 2013; 11:24-39. [PMID: 24215280 DOI: 10.1021/mp400419k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A wide variety of chemotherapy and radiotherapy agents are available for treating cancer, but a critical challenge is to deliver these agents locally to cancer cells and tumors while minimizing side effects from systemic delivery. Nanomedicine uses nanoparticles with diameters in the range of ∼1-100 nm to encapsulate drugs and target them to tumors. The nanoparticle enhances local drug delivery efficiency to the tumors via entrapment in leaky tumor vasculature, molecular targeting to cells expressing cancer biomarkers, and/or magnetic targeting. In addition, the localization can be enhanced using triggered release in tumors via chemical, thermal, or optical signals. In order to optimize these nanoparticle drug delivery strategies, it is important to be able to image where the nanoparticles distribute and how rapidly they release their drug payloads. This Review aims to evaluate the current state of nanotechnology platforms for cancer theranostics (therapeutic and diagnostic particles) that are capable of noninvasive measurement of release kinetics.
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Affiliation(s)
- Thomas Moore
- Department of Bioengineering, and ‡Department of Chemistry, Clemson University , Clemson, South Carolina 29634, United States
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Udartseva OO, Andreeva ER, Buravkova LB. Accumulation and elimination of photosens and protoporphyrin IX by different types of mesenchymal cells. Bull Exp Biol Med 2013; 155:568-71. [PMID: 24143387 DOI: 10.1007/s10517-013-2197-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We studied the kinetics of accumulation and elimination of Photosens and accumulation of protoporphyrin IX in macrophages, endothelial cells, and mesenchymal stromal cells of the human adipose tissue in vitro. In all studied cells, the dynamics of Photosens accumulation was described by a multiphase curve and the maximum accumulation of the dye was observed during the second exponential phase. Elimination of Photosens did not depend on the cell function. Accumulation of protoporphyrin IX differed considerably in different cells: it was maximum in mesenchymal stromal cells was practically not detected in endothelial cells. Accumulation of the dye by macrophages depended on individual donor characteristics.
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Affiliation(s)
- O O Udartseva
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia.
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Weston MA, Patterson MS. Monitoring oxygen concentration during photodynamic therapy using prompt photosensitizer fluorescence. Phys Med Biol 2013; 58:7039-59. [PMID: 24051952 DOI: 10.1088/0031-9155/58/20/7039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A novel technique is described that uses either time-resolved or steady state prompt photosensitizer fluorescence to measure local oxygen concentration. Solution experiments conducted with Al(III) phthalocyanine chloride tetrasulfonic acid confirmed that the steady state fluorescence signal is dependent on the oxygen concentration and fluence rate. A relationship between prompt sensitizer fluorescence and sensitizer triplet quenching efficiency is derived which does not require knowledge of the Stern-Volmer constant. Similar relationships are also derived for sensitizer delayed fluorescence and phosphorescence. An explicit photodynamic therapy (PDT) dose metric that incorporates light dosimetry, sensitizer dosimetry, and triplet quenching efficiency is introduced. All components of this metric can be determined by optical measurements.
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Affiliation(s)
- Mark A Weston
- Juravinski Cancer Centre, Physics Research, 699 Concession St., Hamilton, Ontario, L8V 5C2, Canada
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Yeh SCA, Diamond KR, Patterson MS, Nie Z, Hayward JE, Fang Q. Monitoring photosensitizer uptake using two photon fluorescence lifetime imaging microscopy. Am J Cancer Res 2012; 2:817-26. [PMID: 23082095 PMCID: PMC3475212 DOI: 10.7150/thno.4479] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/18/2012] [Indexed: 11/05/2022] Open
Abstract
Photodynamic Therapy (PDT) provides an opportunity for treatment of various invasive tumors by the use of a cancer targeting photosensitizing agent and light of specific wavelengths. However, real-time monitoring of drug localization is desirable because the induction of the phototoxic effect relies on interplay between the dosage of localized drug and light. Fluorescence emission in PDT may be used to monitor the uptake process but fluorescence intensity is subject to variability due to scattering and absorption; the addition of fluorescence lifetime may be beneficial to probe site-specific drug-molecular interactions and cell damage. We investigated the fluorescence lifetime changes of Photofrin(®) at various intracellular components in the Mat-LyLu (MLL) cell line. The fluorescence decays were analyzed using a bi-exponential model, followed by segmentation analysis of lifetime parameters. When Photofrin(®) was localized at the cell membrane, the slow lifetime component was found to be significantly shorter (4.3 ± 0.5 ns) compared to those at other locations (cytoplasm: 7.3 ± 0.3 ns; mitochondria: 7.0 ± 0.2 ns, p < 0.05).
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Lim J, Jung JH, Lee S, Su Z, Qiang Z, Cha JM, Lee JK, Soh KS. Estimating the density of fluorescent nanoparticles in the primo vessels in the fourth ventricle and the spinal cord of a rat. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:116010. [PMID: 22112115 DOI: 10.1117/1.3647595] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The primo vascular system is a novel circulatory system forming a network throughout an animal's body. Primo vessels were recently observed in the fourth ventricle of the brain and in the spinal cord of a rat by using fluorescent nanoparticles. In order to quantify the nanoparticles in the primo vessels, we measured the florescence of the nanoparticles and calibrated the measurements by using a reference suspension. We removed the noise due to autofluorescence with the technique of multispectral imaging. The line densities of nanoparticles and the contrast values of their images were, respectively, 0.5 ± 0.5 ng/mm and 0.7 ± 0.5 for primo vessels in the fourth ventricle, and 1.3 ± 0.6 ng/mm and 1.4 ± 0.2 for primo vessels in the spinal cord. The data obtained from and the procedures used in this work could be useful in evaluating the feasibility of using nanoparticles as a contrast agent during MRI or CT imaging of primo vessels in the brain or the spinal cord.
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Affiliation(s)
- Jaekwan Lim
- Seoul National University, Nano Primo Research Center, Advanced Institutes of Convergence Technology, Yeongtong-gu, Suwon-si, Gyeonggi-do, Republic of Korea
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Affiliation(s)
- Mikhail Y. Berezin
- Department of Radiology, Washington University School of Medicine, 4525 Scott Ave, St. Louis, USA, Tel. 314-747-0701, 314-362-8599, fax 314-747-5191
| | - Samuel Achilefu
- Department of Radiology, Washington University School of Medicine, 4525 Scott Ave, St. Louis, USA, Tel. 314-747-0701, 314-362-8599, fax 314-747-5191
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Maarek JMI, Holschneider DP. Estimation of indocyanine green concentration in blood from fluorescence emission: application to hemodynamic assessment during hemodialysis. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:054006. [PMID: 19895108 DOI: 10.1117/1.3233652] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
There is considerable interest in assessing cardiovascular function noninvasively in patients receiving hemodialysis. A possible approach is to measure the blood concentration of bolus-injected indocyanine green dye and to apply the dye-dilution method for estimating cardiac output and blood volume. Blood ICG concentration can be derived from a measurement of the ICG fluorescence through the dialysis tubing if a simple and unique calibration relationship can be established between transmural fluorescence intensity and blood ICG concentration. We investigated this relationship using Monte Carlo simulations of light transport in blood with varying hematocrit and ICG concentrations and performed empiric measurements of optical absorption and ICG fluorescence emission to confirm our findings. The ICG fluorescence intensity measured at the blood surface, as well as the light intensity remitted by the blood, varied as hematocrit changes modified the absorption and scattering characteristics of the blood. Calibration relationships were developed between fluorescence intensity and ICG concentration that accounted for hematocrit changes. Combining the backreflected fluorescence and the reflected light measured near the point of illumination provided optimal signal intensity, linearity, and robustness to hematocrit changes. These results provide a basis for developing a noninvasive approach to derive optically circulating blood ICG concentration in hemodialysis circuits.
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Affiliation(s)
- Jean-Michel I Maarek
- University of Southern California, Department of Biomedical Engineering and Alfred E. Mann Institute for Biomedical Engineering, Denney Research Center 140, 1042 Downey Way, Los Angeles, California 90089, USA.
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Kruijt B, Kascakova S, de Bruijn HS, van der Ploeg-van den Heuvel A, Sterenborg HJCM, Robinson DJ, Amelink A. In vivo quantification of chromophore concentration using fluorescence differential path length spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:034022. [PMID: 19566315 DOI: 10.1117/1.3149862] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present an optical method based on fluorescence spectroscopy for measuring chromophore concentrations in vivo. Fluorescence differential path length spectroscopy (FPDS) determines chromophore concentration based on the fluorescence intensity corrected for absorption. The concentration of the photosensitizer m-THPC (Foscan) was studied in vivo in normal rat liver, which is highly vascularized and therefore highly absorbing. Concentration estimates of m-THPC measured by FDPS on the liver are compared with chemical extraction. Twenty-five rats were injected with 0.3 mg kg m-THPC. In vivo optical concentration measurements were performed on tissue 3, 24, 48, and 96 h after m-THPC administration to yield a 10-fold variation in tissue concentration. After the optical measurements, the liver was harvested for chemical extraction. FDPS showed good correlation with chemical extraction. FDPS also showed a correlation between m-THPC fluorescence and blood volume fraction at the two shortest drug-light intervals. This suggests different compartmental localization of m-THPC for different drug-light intervals that can be resolved using fluorescence spectroscopy. Differences in measured m-THPC concentration between FDPS and chemical extraction are related to the interrogation volume of each technique; approximately 0.2 mm(3) and approximately 10(2) mm(3), respectively. This indicates intra-animal variation in m-THPC distribution in the liver on the scale of the FDPS sampling volume.
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Affiliation(s)
- Bastiaan Kruijt
- Centre for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus MC Room Ee1675, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
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12
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Weston MA, Patterson MS. Simple Photodynamic Therapy Dose Models Fail to Predict the Survival of MLL Cells After HPPH-PDTIn Vitro. Photochem Photobiol 2009; 85:750-9. [DOI: 10.1111/j.1751-1097.2008.00494.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Effets de la fluorescence résiduelle dans les tissus biologiques sur les signaux de fluorescence résolus temporellement par la méthode des éléments finis. Ing Rech Biomed 2008. [DOI: 10.1016/j.rbmret.2007.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Kascáková S, Kruijt B, de Bruijn HS, van der Ploeg-van den Heuvel A, Robinson DJ, Sterenborg HJCM, Amelink A. Ex vivo quantification of mTHPC concentration in tissue: influence of chemical extraction on the optical properties. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2008; 91:99-107. [PMID: 18359242 DOI: 10.1016/j.jphotobiol.2008.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 02/12/2008] [Accepted: 02/12/2008] [Indexed: 11/24/2022]
Abstract
A method for the quantification of the concentration of the photosensitizer meso-tetra(hydroxyphenyl) chlorin (mTHPC) in tissue samples is presented. The technique is an extension of a previously published method based on alkaline hydrolysis of tissue, using Solvable as a tissue solubilizer. mTHPC quantification was achieved by subsequent fluorescence spectroscopy. Since the original extraction method involved multiple steps in which water dilution of the sample was implemented, we studied the spectral characteristics of mTHPC in different Solvable/water mixtures. Using UV-VIS absorption and fluorescence spectroscopy, it was demonstrated that the spectral characteristics of mTHPC vary for different Solvable concentrations. In the range of 20-100% Solvable, the fluorescence intensity of mTHPC did not change, while dramatic changes in the mTHPC fluorescence intensity were observed for lower Solvable concentrations (< 20%) due to increasing hydrophilicity of the environment, combined with pH alterations. We also demonstrated that the absorption and fluorescence spectra of the dissolved tissue were time-dependent. Longer incubation of the samples resulted in a significant increase of the native tissue chromophore fluorescence. This implies that for the correct quantification of photosensitizer concentrations, the fluorescence of native tissue chromophores must be accounted for.
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Affiliation(s)
- Slávka Kascáková
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus Medical Center, Westzeedijk 118, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
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Stepp H, Beck T, Beyer W, Pfaller C, Schuppler M, Sroka R, Baumgartner R. Measurement of fluorophore concentration in turbid media by a single optical fiber. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.mla.2006.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Wang HW, Finlay JC, Lee K, Zhu TC, Putt ME, Glatstein E, Koch CJ, Evans SM, Hahn SM, Busch TM, Yodh AG. Quantitative comparison of tissue oxygen and motexafin lutetium uptake by ex vivo and noninvasive in vivo techniques in patients with intraperitoneal carcinomatosis. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:034023. [PMID: 17614731 DOI: 10.1117/1.2743082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Near-infrared diffuse reflectance spectroscopy (DRS) has been used to noninvasively monitor optical properties during photodynamic therapy (PDT). This technique has been extensively validated in tissue phantoms; however, validation in patients has been limited. This pilot study compares blood oxygenation and photosensitizer tissue uptake measured by multiwavelength DRS with ex vivo assays of the hypoxia marker, 2-(2-nitroimida-zol-1[H]-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5), and the photosensitizer (motexafin lutetium, MLu) from tissues at the same tumor site of three tumors in two patients with intra-abdominal cancers. Similar in vivo and ex vivo measurements of MLu concentration are carried out in murine radiation-induced fibrosarcoma (RIF) tumors (n=9). The selection of optimal DRS wavelength range and source-detector separations is discussed and implemented, and the association between in vivo and ex vivo measurements is examined. The results demonstrate a negative correlation between blood oxygen saturation (StO(2)) and EF5 binding, consistent with published relationships between EF5 binding and electrode measured pO(2), and between electrode measured pO(2) and StO(2). A tight correspondence is observed between in vivo DRS and ex vivo measured MLu concentration in the RIF tumors; similar data are positively correlated in the human intraperitoneal tumors. These results further demonstrate the potential of in vivo DRS measurements in clinical PDT.
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Affiliation(s)
- Hsing-Wen Wang
- University of Pennsylvania, Department of Physics, Philadelphia, Pennsylvania, USA.
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Kervella M, Humeau A, L'Huillier JP. Effects of residual fluorescence on time-resolved signals simulated with the finite element method in biological tissues. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2007; 2007:5976-5979. [PMID: 18003375 DOI: 10.1109/iembs.2007.4353709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A computational model based on finite element method is derived to examine how the simulated time-dependent signals are related to the presence of residual fluorescence in biological media surrounding a fluorescent object. We apply a subtraction technique on recorded data when imperfect uptake of fluorescing agent into the tumor is considered. We show the limits of the subtracting method for low target: background fluorescent absorption contrast by extracting the time to reach the half maximum and analyzing the maximum of the time-resolved signals versus target depth.
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Affiliation(s)
- Marine Kervella
- Groupe ISAIP-ESAIP, 18 rue du 8 mai 1945, BP 80022, 49180 Saint Barthélémy d'Anjou cedex, France.
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Stringer MR, Kelty CJ, Ackroyd R, Brown SB. Light dosimetry measurements during ALA-PDT of Barrett's oesophagus. Photodiagnosis Photodyn Ther 2006; 3:19-26. [PMID: 25049024 DOI: 10.1016/s1572-1000(05)00155-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Revised: 11/24/2005] [Accepted: 11/28/2005] [Indexed: 11/28/2022]
Abstract
A fibre optic probe and compact light detection system has been used to monitor the fluence-rate at the tissue surface during 5-aminolaevulinic acid based photodynamic therapy (PDT) of Barrett's oesophagous. The contributions from three specific wavelengths were recorded, corresponding to the combination of therapeutic laser light and fluorescence emission from protoporphyrin IX (635nm), the fluorescence from an oxidation product of the photosensitiser (670nm), and the protoporphyrin IX fluorescence alone (705nm). We have found that light scattering results in an enhancement of the therapeutic fluence-rate, and hence light dose, by approximately 70%. At the onset of therapy the fluorescence provides a 10% contribution to the overall fluence-rate at 635nm. The dynamics of photosensitiser bleaching could be extracted from the depletion in light signals. By defining a bleaching dose as the 635nm light fluence delivered over the period during which the photosensitiser fluorescence decays to 1/e(3) of its initial value, we find that the average ratio of bleaching to total dose is 33%. Further, the fluorescence contributes approximately 5% of the bleaching light dose. These results suggest that the prescribed period of therapeutic light exposure may be reduced with no loss in clinical efficacy, but with a consequent improvement in patient tolerance to this therapy.
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Affiliation(s)
- M R Stringer
- Institute of Microwaves and Photonics, School of Electronic and Electrical Engineering, University of Leeds, UK
| | - C J Kelty
- Department of Surgery, Royal Hallamshire Hospital, Sheffield, UK
| | - R Ackroyd
- Department of Surgery, Royal Hallamshire Hospital, Sheffield, UK
| | - S B Brown
- Centre for Photobiology and Photodynamic Therapy, School of Biochemistry and Microbiology, University of Leeds, UK
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