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Xu R, Teich W, Frenzel F, Hoffmann K, Radke J, Rösler J, Faust K, Blank A, Brandenburg S, Misch M, Vajkoczy P, Onken JS, Resch-Genger U. Optical Characterization of Sodium Fluorescein In Vitro and Ex Vivo. Front Oncol 2021; 11:654300. [PMID: 34041024 PMCID: PMC8141558 DOI: 10.3389/fonc.2021.654300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/07/2021] [Indexed: 01/18/2023] Open
Abstract
Objective The utilization of fluorescein-guided biopsies and resection has been recently discussed as a suitable strategy to improve and expedite operative techniques for the resection of central nervous system (CNS) tumors. However, little is known about the optical properties of sodium fluorescein (NaFl) in human tumor tissue and their potential impact on ex vivo analyses involving fluorescence-based methods. Methods Tumor tissue was obtained from a study cohort of an observational study on the utilization of fluorescein-guided biopsy and resection (n=5). The optical properties of fluorescein-stained tissue were compared to the optical features of the dye in vitro and in control samples consisting of tumor tissue of high-grade glioma patients (n=3) without intravenous (i.v.) application of NaFl. The dye-exposed tumor tissues were used for optical measurements to confirm the detectability of NaFl emission ex vivo. The tissue samples were fixed in 4%PFA, immersed in 30% sucrose, embedded in Tissue-Tek OCT compound, and cut to 10 μm cryosections. Spatially resolved emission spectra from tumor samples were recorded on representative slides with a Confocal Laser Scanning Microscope FV1000 (Olympus GmbH, Hamburg, Germany) upon excitation with λexc = 488 nm. Results Optical measurements of fluorescein in 0.9% sodium chloride (NaCl) under in vitro conditions showed an absorption maximum of λmax abs = 479 nm as detected with spectrophotometer Specord 200 and an emission peak at λmax em = 538 nm recorded with the emCCD detection system of a custom-made microscope-based single particle setup using a 500 nm long-pass filter. Further measurements revealed pH- and concentration-dependent emission spectra of NaFl. Under ex vivo conditions, confocal laser scanning microscopy of fluorescein tumor samples revealed a slight bathochromic shift and a broadening of the emission band. Conclusion Tumor uptake of NaFl leads to changes in the optical properties – a bathochromic shift and broadening of the emission band – possibly caused by the dye’s high pH sensitivity and concentration-dependent reabsorption acting as an inner filter of the dye’s emission, particularly in the short wavelength region of the emission spectrum where absorption and fluorescence overlap. Understanding the ex vivo optical properties of fluorescein is crucial for testing and validating its further applicability as an optical probe for intravital microscopy, immunofluorescence localization studies, and flow cytometry analysis.
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Affiliation(s)
- Ran Xu
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Wanda Teich
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Florian Frenzel
- Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Berlin, Germany
| | - Katrin Hoffmann
- Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Berlin, Germany
| | - Josefine Radke
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany, partner site Charité Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Judith Rösler
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Katharina Faust
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anne Blank
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Susan Brandenburg
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Martin Misch
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Julia Sophie Onken
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany, partner site Charité Berlin, Berlin, Germany
| | - Ute Resch-Genger
- Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Berlin, Germany
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Abstract
The selective amplification of DNA in the polymerase chain reaction is used to exponentially increase the signal in molecular diagnostics for nucleic acids, but there are no analogous techniques for signal enhancement in clinical tests for proteins or cells. Instead, the signal from affinity-based measurements of these biomolecules depends linearly on the probe concentration. Substituting antibody-based probes tagged for fluorescent quantification with lasing detection probes would create a new platform for biomarker quantification based on optical rather than enzymatic amplification. Here, we construct a virus laser which bridges synthetic biology and laser physics, and demonstrate virus-lasing probes for biosensing. Our virus-lasing probes display an unprecedented > 10,000 times increase in signal from only a 50% increase in probe concentration, using fluorimeter-compatible optics, and can detect biomolecules at sub-100 fmol mL−1 concentrations. Many ligand-binding assays still rely on signals that scale linearly with probe concentration. The authors present lasing detection probes with a dye-labelled virus as the gain medium to optically amplify the signal, which could enable much higher signals than for fluorescent quantification.
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Eisold U, Sellrie F, Schenk JA, Lenz C, Stöcklein WFM, Kumke MU. Bright or dark immune complexes of anti-TAMRA antibodies for adapted fluorescence-based bioanalysis. Anal Bioanal Chem 2015; 407:3313-23. [PMID: 25711988 DOI: 10.1007/s00216-015-8538-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 01/14/2015] [Accepted: 02/06/2015] [Indexed: 11/26/2022]
Abstract
Fluorescence labels, for example fluorescein or rhodamin derivatives, are widely used in bioanalysis applications including lateral-flow assays, PCR, and fluorescence microscopy. Depending on the layout of the particular application, fluorescence quenching or enhancement may be desired as the detection principle. Especially for multiplexed applications or high-brightness requirements, a tunable fluorescence probe can be beneficial. The alterations in the photophysics of rhodamine derivatives upon binding to two different anti-TAMRA antibodies were investigated by absorption and fluorescence-spectroscopy techniques, especially determining the fluorescence decay time and steady-state and time-resolved fluorescence anisotropy. Two monoclonal anti-TAMRA antibodies were generated by the hybridoma technique. Although surface-plasmon-resonance measurements clearly proved the high affinity of both antibodies towards 5-TAMRA, the observed effects on the fluorescence of rhodamine derivatives were very different. Depending on the anti-TAMRA antibody either a strong fluorescence quenching (G71-DC7) or a distinct fluorescence enhancement (G71-BE11) upon formation of the immune complex was observed. Additional rhodamine derivatives were used to gain further information on the binding interaction. The data reveal that such haptens as 5-TAMRA could generate different paratopes with equal binding affinities but different binding interactions, which provide the opportunity to adapt bioanalysis methods including immunoassays for optimized detection principles for the same hapten depending on the specific requirements.
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Affiliation(s)
- Ursula Eisold
- Department of Chemistry, Physical Chemistry, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
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Pinheiro PC, Daniel-da-Silva AL, Tavares DS, Calatayud MP, Goya GF, Trindade T. Fluorescent Magnetic Bioprobes by Surface Modification of Magnetite Nanoparticles. MATERIALS 2013; 6:3213-3225. [PMID: 28811431 PMCID: PMC5521243 DOI: 10.3390/ma6083213] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 06/28/2013] [Accepted: 07/23/2013] [Indexed: 12/11/2022]
Abstract
Bimodal nanoprobes comprising both magnetic and optical functionalities have been prepared via a sequential two-step process. Firstly, magnetite nanoparticles (MNPs) with well-defined cubic shape and an average dimension of 80 nm were produced by hydrolysis of iron sulfate and were then surface modified with silica shells by using the sol-gel method. The Fe₃O₄@SiO₂ particles were then functionalized with the fluorophore, fluorescein isothiocyanate (FITC), mediated by assembled shells of the cationic polyelectrolyte, polyethyleneimine (PEI). The Fe₃O₄ functionalized particles were then preliminary evaluated as fluorescent and magnetic probes by performing studies in which neuroblast cells have been contacted with these nanomaterials.
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Affiliation(s)
- Paula C Pinheiro
- Department of Chemistry-CICECO (Centre for Research in Ceramics and Composite Materials), Aveiro Institute of Nanotechnology, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Ana L Daniel-da-Silva
- Department of Chemistry-CICECO (Centre for Research in Ceramics and Composite Materials), Aveiro Institute of Nanotechnology, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Daniela S Tavares
- Department of Chemistry-CICECO (Centre for Research in Ceramics and Composite Materials), Aveiro Institute of Nanotechnology, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - M Pilar Calatayud
- Institute of Nanoscience of Aragón (INA), University of Zaragoza, 50018 Zaragoza, Spain.
| | - Gerardo F Goya
- Institute of Nanoscience of Aragón (INA), University of Zaragoza, 50018 Zaragoza, Spain.
| | - Tito Trindade
- Department of Chemistry-CICECO (Centre for Research in Ceramics and Composite Materials), Aveiro Institute of Nanotechnology, University of Aveiro, 3810-193 Aveiro, Portugal.
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Ranjit S, Levitus M. Probing the interaction between fluorophores and DNA nucleotides by fluorescence correlation spectroscopy and fluorescence quenching. Photochem Photobiol 2012; 88:782-91. [PMID: 22364288 DOI: 10.1111/j.1751-1097.2012.01121.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated the association interactions between the fluorescent dyes TAMRA, Cy3B and Alexa-546 and the DNA deoxynucleoside monophosphates by means of fluorescence quenching and fluorescence correlation spectroscopy (FCS). The interactions of Cy3B and TAMRA with the nucleotides produce a decrease in the apparent diffusion coefficient of the dyes, which result in a shift toward longer times in the FCS autocorrelation decays. Our results with Cy3B demonstrate the existence of Cy3B-nucleotide interactions that do not affect the fluorescence intensity or lifetime of the dye significantly. The same is true for TAMRA in the presence of dAMP, dCMP and dTMP. In contrast, the diffusion coefficient of Alexa 546 remains practically unchanged even at high concentrations of nucleotide. These results demonstrate that interactions between this dye and the four dNMPs are not significant. The presence of the negatively charged sulfonates and the bulky chlorine atoms in the phenyl group of Alexa 546 possibly prevent strong interactions that are otherwise possible for TAMRA. The characterization of dye-DNA interactions is important in biophysical research because they play an important role in the interpretation of energy transfer experiments, and because they can potentially affect the structure and dynamics of the DNA.
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Affiliation(s)
- Suman Ranjit
- Department of Chemistry and Biochemistry and Biodesign Institute, Arizona State University, Tempe, AZ, USA
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Zhang LS, Mummert ME. Development of a fluorescent substrate to measure hyaluronidase activity. Anal Biochem 2008; 379:80-5. [PMID: 18492482 DOI: 10.1016/j.ab.2008.04.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 04/18/2008] [Accepted: 04/23/2008] [Indexed: 11/16/2022]
Abstract
A novel fluorescent substrate (termed FRET-HA) to quantitatively assess hyaluronidase activity was developed. Hyaluronan (HA), the major substrate for hyaluronidase, was dual labeled with fluorescein amine and rhodamine B amine. The fluorescein amine fluorescence signal was significantly quenched and the rhodamine B amine signal was significantly enhanced due to fluorescence resonance energy transfer (FRET). In the presence of bovine testes hyaluronidase, cleavage of HA disrupted FRET, resulting in a loss of the fluorescein amine quenching that was dependent on both enzyme concentration and time. Increase in the fluorescein amine signal could be conveniently monitored in both noncontinuous and continuous fashions. The K(m) value for bovine testes hyaluronidase was determined using FRET-HA in a continuous fluorescent assay. Importantly, the estimated K(m) value for bovine testes hyaluronidase using FRET-HA as the substrate was in excellent agreement with K(m) values reported previously for this enzyme using native (i.e., unlabeled) HA. Therefore, FRET-HA is a reliable substrate for quantitatively assessing the HA/hyaluronidase molecular interaction. The simplicity, sensitivity, and versatility of the FRET-HA substrate suggest that it will have utility in a variety of assay platforms and should be a new tool for assessing hyaluronidase activity.
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Affiliation(s)
- Li-Shu Zhang
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Hungerford G, Benesch J, Mano JF, Reis RL. Effect of the labelling ratio on the photophysics of fluorescein isothiocyanate (FITC) conjugated to bovine serum albumin. Photochem Photobiol Sci 2006; 6:152-8. [PMID: 17277838 DOI: 10.1039/b612870j] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The non-linearity of the fluorescence emission on increasing the probe to protein ratio has long been regarded as problematic and has lead to the development of dyes to overcome this effect. One of the causes of this non-linear response can be ascribed to the overlap of the label's own absorption and emission spectra. At higher labelling ratios, this affords the possibility of a reasonably efficient energy migration pathway, thus reducing the observed quantum yield of the dye. In this work we study the photophysics of fluorescein isothiocyanate (FITC) when conjugated to bovine serum albumin (BSA) at different labelling ratios (in the range FITC : BSA 1 : 17-15 : 1) using both steady state and time-resolved fluorescence techniques where on going from under labelled to over labelled samples a decrease in the initial (and steady state) anisotropy is observed, accompanied by an increase in the complexity of the decay kinetics and a decrease in the average lifetime. The band structure, elucidated by synchronous scan fluorescence spectroscopy, is also found to change on increased labelling. These results can be applied to the study of protein conformation and were confirmed by the analysis of denaturing BSA using urea.
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Affiliation(s)
- Graham Hungerford
- Departamento de Fisica, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
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Rucker VC, Dunn AR, Sharma S, Dervan PB, Gray HB. Mechanism of Sequence-Specific Fluorescent Detection of DNA by N-Methyl-imidazole, N-Methyl-pyrrole, and β-Alanine Linked Polyamides. J Phys Chem B 2004. [DOI: 10.1021/jp037423i] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Victor C. Rucker
- Division of Chemistry and Chemical Engineering and the Beckman Institute, California Institute of Technology, Pasadena, California 91125
| | - Alexander R. Dunn
- Division of Chemistry and Chemical Engineering and the Beckman Institute, California Institute of Technology, Pasadena, California 91125
| | - Shantanu Sharma
- Division of Chemistry and Chemical Engineering and the Beckman Institute, California Institute of Technology, Pasadena, California 91125
| | - Peter B. Dervan
- Division of Chemistry and Chemical Engineering and the Beckman Institute, California Institute of Technology, Pasadena, California 91125
| | - Harry B. Gray
- Division of Chemistry and Chemical Engineering and the Beckman Institute, California Institute of Technology, Pasadena, California 91125
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