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McConnell G, Mabbott S, Kanibolotsky AL, Skabara PJ, Graham D, Burley GA, Laurand N. Organic Semiconductor Laser Platform for the Detection of DNA by AgNP Plasmonic Enhancement. Langmuir 2018; 34:14766-14773. [PMID: 30227713 DOI: 10.1021/acs.langmuir.8b01313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Organic semiconductor lasers are a sensitive biosensing platform that respond to specific biomolecule binding events. So far, such biosensors have utilized protein-based interactions for surface functionalization but a nucleic acid-based strategy would considerably widen their utility as a general biodiagnostic platform. This manuscript reports two important advances for DNA-based sensing using an organic semiconductor (OS) distributed feedback (DFB) laser. First, the immobilization of alkyne-tagged 12/18-mer oligodeoxyribonucleotide (ODN) probes by Cu-catalyzed azide alkyne cycloaddition (CuAAC) or "click-chemistry" onto an 80 nm thick OS laser film modified with an azide-presenting polyelectrolyte monolayer is presented. Second, sequence-selective binding to these immobilized probes with complementary ODN-functionalized silver nanoparticles, is detected. As binding occurs, the nanoparticles increase the optical losses of the laser mode through plasmonic scattering and absorption, and this causes a rise in the threshold pump energy required for laser action that is proportional to the analyte concentration. By monitoring this threshold, detection of the complementary ODN target down to 11.5 pM is achieved. This complementary binding on the laser surface is independently confirmed through surface-enhanced Raman spectroscopy (SERS).
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Affiliation(s)
- G McConnell
- Institute of Photonics, Department of Physics , University of Strathclyde , Glasgow G12 8QQ , U.K
- Biomedical Engineering , University of Strathclyde , Glasgow G12 8QQ , U.K
| | - S Mabbott
- WestCHEM, Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow G12 8QQ , U.K
| | - A L Kanibolotsky
- WestCHEM, School of Chemistry , University of Glasgow , Glasgow G12 8QQ , U.K
- Institute of Physical-Organic and Coal Chemistry , The National Academy of Sciences of Ukraine , 02160 Kyiv , Ukraine
| | - P J Skabara
- WestCHEM, School of Chemistry , University of Glasgow , Glasgow G12 8QQ , U.K
| | - D Graham
- WestCHEM, Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow G12 8QQ , U.K
| | - G A Burley
- WestCHEM, Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow G12 8QQ , U.K
| | - N Laurand
- Institute of Photonics, Department of Physics , University of Strathclyde , Glasgow G12 8QQ , U.K
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2
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McConnell G, Amos WB. Application of the Mesolens for subcellular resolution imaging of intact larval and whole adult Drosophila. J Microsc 2018; 270:252-258. [PMID: 29570774 PMCID: PMC5947746 DOI: 10.1111/jmi.12693] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/31/2018] [Accepted: 02/17/2018] [Indexed: 01/23/2023]
Abstract
In a previous paper, we showed a new giant lens called the Mesolens and presented performance data and images from whole fixed and intact fluorescently‐stained 12.5‐day old mouse embryos. Here, we show that using the Mesolens we can image an entire Drosophila larva or adult fly in confocal epifluorescence and show subcellular detail in all tissues. By taking several hundreds of optical sections through the entire volume of the specimen, we show cells and nuclear details within the gut, brain, salivary glands and reproductive system that normally require dissection for study. Organs are imaged in situ in correct 3D arrangement. Imaginal discs are imaged in mature larvae and it proved possible to image pachytene chromosomes in cells within ovarian follicles in intact female flies. Methods for fixing, staining and clearing are given.
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Affiliation(s)
- G McConnell
- Department of Physics, SUPA, University of Strathclyde, Glasgow, U.K
| | - W B Amos
- Department of Physics, SUPA, University of Strathclyde, Glasgow, U.K.,MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, U.K
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3
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Tinning PW, Franssen AJPM, Hridi SU, Bushell TJ, McConnell G. A 340/380 nm light-emitting diode illuminator for Fura-2 AM ratiometric Ca 2+ imaging of live cells with better than 5 nM precision. J Microsc 2017; 269:212-220. [PMID: 28837217 PMCID: PMC5836901 DOI: 10.1111/jmi.12616] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 01/17/2023]
Abstract
We report the first demonstration of a fast wavelength‐switchable 340/380 nm light‐emitting diode (LED) illuminator for Fura‐2 ratiometric Ca2+ imaging of live cells. The LEDs closely match the excitation peaks of bound and free Fura‐2 and enables the precise detection of cytosolic Ca2+ concentrations, which is only limited by the Ca2+ response of Fura‐2. Using this illuminator, we have shown that Fura‐2 acetoxymethyl ester (AM) concentrations as low as 250 nM can be used to detect induced Ca2+ events in tsA‐201 cells and while utilising the 150 μs switching speeds available, it was possible to image spontaneous Ca2+ transients in hippocampal neurons at a rate of 24.39 Hz that were blunted or absent at typical 0.5 Hz acquisition rates. Overall, the sensitivity and acquisition speeds available using this LED illuminator significantly improves the temporal resolution that can be obtained in comparison to current systems and supports optical imaging of fast Ca2+ events using Fura‐2.
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Affiliation(s)
- P W Tinning
- Department of Physics, SUPA University of Strathclyde, Glasgow, U.K
| | - A J P M Franssen
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - S U Hridi
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - T J Bushell
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - G McConnell
- Centre for Biophotonics, University of Strathclyde, Glasgow, U.K
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4
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Trägårdh J, Robb G, Amor R, Amos WB, Dempster J, McConnell G. Exploration of the two-photon excitation spectrum of fluorescent dyes at wavelengths below the range of the Ti:Sapphire laser. J Microsc 2015; 259:210-8. [PMID: 25946127 PMCID: PMC4700633 DOI: 10.1111/jmi.12255] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
We have studied the wavelength dependence of the two-photon excitation efficiency for a number of common UV excitable fluorescent dyes; the nuclear stains DAPI, Hoechst and SYTOX Green, chitin- and cellulose-staining dye Calcofluor White and Alexa Fluor 350, in the visible and near-infrared wavelength range (540-800 nm). For several of the dyes, we observe a substantial increase in the fluorescence emission intensity for shorter excitation wavelengths than the 680 nm which is the shortest wavelength usually available for two-photon microscopy. We also find that although the rate of photo-bleaching increases at shorter wavelengths, it is still possible to acquire many images with higher fluorescence intensity. This is particularly useful for applications where the aim is to image the structure, rather than monitoring changes in emission intensity over extended periods of time. We measure the excitation spectrum when the dyes are used to stain biological specimens to get a more accurate representation of the spectrum of the dye in a cell environment as compared to solution-based measurements.
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Affiliation(s)
- J Trägårdh
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - G Robb
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - R Amor
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - W B Amos
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
- MRC Laboratory of Molecular Biology, Cambridge, U.K
| | - J Dempster
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - G McConnell
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
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5
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Trägårdh J, Macrae K, Travis C, Amor R, Norris G, Wilson SH, Oppo GL, McConnell G. A simple but precise method for quantitative measurement of the quality of the laser focus in a scanning optical microscope. J Microsc 2015; 259:66-73. [PMID: 25864964 PMCID: PMC4975716 DOI: 10.1111/jmi.12249] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/24/2015] [Indexed: 12/03/2022]
Abstract
We report a method for characterizing the focussing laser beam exiting the objective in a laser scanning microscope. This method provides the size of the optical focus, the divergence of the beam, the ellipticity and the astigmatism. We use a microscopic‐scale knife edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide, and a light‐collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, a beam profile in the form of an error function can be obtained and by repeating this with the knife edge at different axial positions relative to the beam waist, the divergence and astigmatism of the postobjective laser beam can be obtained. The measured divergence can be used to quantify how much of the full numerical aperture of the lens is used in practice. We present data of the beam radius, beam divergence, ellipticity and astigmatism obtained with low (0.15, 0.7) and high (1.3) numerical aperture lenses and lasers commonly used in confocal and multiphoton laser scanning microscopy. Our knife‐edge method has several advantages over alternative knife‐edge methods used in microscopy including that the knife edge is easy to prepare, that the beam can be characterized also directly under a cover slip, as necessary to reduce spherical aberrations for objectives designed to be used with a cover slip, and it is suitable for use with commercial laser scanning microscopes where access to the laser beam can be limited.
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Affiliation(s)
- J Trägårdh
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - K Macrae
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K.,Department of Physics, University of Strathclyde, Glasgow, U.K
| | - C Travis
- Department of Physics, University of Strathclyde, Glasgow, U.K
| | - R Amor
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - G Norris
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - S H Wilson
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K.,Department of Physics, University of Strathclyde, Glasgow, U.K
| | - G-L Oppo
- Department of Physics, University of Strathclyde, Glasgow, U.K
| | - G McConnell
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
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6
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Travis C, Norris G, McConnell G, Oppo GL. Energy shedding during nonlinear self-focusing of optical beams. Opt Express 2013; 21:23459-23470. [PMID: 24104260 DOI: 10.1364/oe.21.023459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Self-focusing of intense laser beams and pulses of light in real nonlinear media is in general accompanied by material losses that require corrections to the conservative Nonlinear Schrödinger equations describing their propagation. Here we examine loss mechanisms that exist even in lossless media and are caused by shedding of energy away from the self-trapping beam making it to relax to an exact solution of lower energy. Using the conservative NLS equations with absorbing boundary conditions we show that energy shedding not only occurs during the initial reshaping process but also during oscillatory propagation induced by saturation of the nonlinear effect. For pulsed input we also show that, depending on the sign and magnitude of dispersion, pulse splitting, energy shedding, collapse or stable self-focusing may result.
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Norris G, Amor R, Dempster J, Amos WB, McConnell G. Increased signals from short-wavelength-excited fluorescent molecules using sub-Ti:Sapphire wavelengths. J Microsc 2012; 248:200-7. [PMID: 23078118 PMCID: PMC3746106 DOI: 10.1111/j.1365-2818.2012.03663.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 08/14/2012] [Indexed: 11/28/2022]
Abstract
We report the use of an all-solid-state ultrashort pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involves sum-frequency mixing of the output from an optical parametric oscillator (λ= 1400-1640 nm) synchronously pumped by a Yb-doped fibre laser (λ= 1064 nm), with the residual pump radiation. This generated an fs-pulsed output tunable in the red spectral region (λ= 620-636 nm, ~150 mW, 405 fs, 80 MHz, M(2) ~ 1.3). We demonstrate the performance of our ultrashort pulsed system using fluorescently labelled and autofluorescent tissue, and compare with conventional Ti:Sapphire excitation. We observe a more than 3-fold increase in fluorescence signal intensity using our visible laser source in comparison with the Ti:Sapphire laser for two-photon excitation at equal illumination peak powers of 1.16 kW or less.
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Affiliation(s)
- G Norris
- Centre for Biophotonics, SIPBS, University of Strathclyde, Glasgow, UK
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8
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Amor R, Norris G, Dempster J, Amos WB, McConnell G. A compact instrument for adjusting laser beams to be accurately coincident and coaxial and its use in biomedical imaging using wave-mixed laser sources. Rev Sci Instrum 2012; 83:083705. [PMID: 22938301 DOI: 10.1063/1.4745373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Biomedical imaging applications that involve nonlinear optical processes such as sum-frequency generation (SFG) and four-wave mixing require that the pulses are synchronized in time and the beams are coaxial to better than 400 μrad. For this reason, folding mirrors are normally used to extend the beam path over a few meters so that detectors can be put into the beams to check their overlap at the start of a long path and also at the end of it. We have made a portable instrument with a footprint of only 22 cm × 11 cm × 16 cm that uses a short focal length lens and a telephoto combination for viewing the near-field and far-field simultaneously. Our instrument is simple to build and use, and we show its application in coherent anti-Stokes Raman scattering microscopy and SFG-based two-photon fluorescence microscopy.
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Affiliation(s)
- R Amor
- Centre for Biophotonics, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom.
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Norris G, McConnell G. Relaxed damage threshold intensity conditions and nonlinear increase in the conversion efficiency of an optical parametric oscillator using a bi-directional pump geometry. Opt Express 2010; 18:3993-3999. [PMID: 20389413 DOI: 10.1364/oe.18.003993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A novel bi-directional pump geometry that nonlinearly increases the nonlinear optical conversion efficiency of a synchronously pumped optical parametric oscillator (OPO) is reported. This bi-directional pumping method synchronizes the circulating signal pulse with two counter-propagating pump pulses within a linear OPO resonator. Through this pump scheme, an increase in nonlinear optical conversion efficiency of 22% was achieved at the signal wavelength, corresponding to a 95% overall increase in average power. Given an almost unchanged measured pulse duration of 260 fs under optimal performance conditions, this related to a signal wavelength peak power output of 18.8 kW, compared with 10 kW using the traditional single-pass geometry. In this study, a total effective peak intensity pump-field of 7.11 GW/cm(2) (corresponding to 3.55 GW/cm(2) from each pump beam) was applied to a 3 mm long periodically poled lithium niobate crystal, which had a damage threshold intensity of 4 GW/cm(2), without impairing crystal integrity. We therefore prove the application of this novel pump geometry provides opportunities for power-scaling of synchronously pumped OPO systems together with enhanced nonlinear conversion efficiency through relaxed damage threshold intensity conditions.
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Affiliation(s)
- G Norris
- Centre for Biophotonics, SIPBS, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, UK.
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10
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McConnell G, Girkin JM, Ameer-Beg SM, Barber PR, Vojnovic B, Ng T, Banerjee A, Watson TF, Cook RJ. Time-correlated single-photon counting fluorescence lifetime confocal imaging of decayed and sound dental structures with a white-light supercontinuum source. J Microsc 2007; 225:126-36. [PMID: 17359247 DOI: 10.1111/j.1365-2818.2007.01724.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We report the demonstration of time-correlated single-photon counting (TCSPC) fluorescence lifetime imaging (FLIM) to ex vivo decayed and healthy dentinal tooth structures, using a white-light supercontinuum excitation source. By using a 100 fs-pulsed Ti:Sapphire laser with a low-frequency chirp to pump a 30-cm long section of photonic crystal fibre, a ps-pulsed white-light supercontinuum was created. Optical bandpass interference filters were then applied to this broad-bandwidth source to select the 488-nm excitation wavelength required to perform TCSPC FLIM of dental structures. Decayed dentine showed significantly shorter lifetimes, discriminating it from healthy tissue and hard, stained and thus affected but non-infected material. The white-light generation source provides a flexible method of producing variable-bandwidth visible and ps-pulsed light for TCSPC FLIM. The results from the dental tissue indicate a potential method of discriminating diseased tissue from sound, but stained tissue, which could be of crucial importance in limiting tissue resection during preparation for clinical restorations.
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Affiliation(s)
- G McConnell
- Centre for Biophotonics, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow, G4 0NR, UK.
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11
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McConnell G. Nonlinear optical microscopy at wavelengths exceeding 1.4 microm using a synchronously pumped femtosecond-pulsed optical parametric oscillator. Phys Med Biol 2007; 52:717-24. [PMID: 17228116 DOI: 10.1088/0031-9155/52/3/013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A singly resonant femtosecond-pulsed synchronously pumped optical parametric oscillator (SPOPO) is reported that provides a wavelength-tunable alternative to the Cr:forsterite source for nonlinear microscopy applications. Periodically poled lithium niobate within an external resonator was synchronously pumped by a commercial fs-pulsed Nd:YLF laser source to provide fs-pulsed continuously tunable radiation from 1.45 to 1.63 microm. Third harmonic generation (THG) microscopy and three-photon laser scanning fluorescence microscopy (3PLSM) of a range of samples were subsequently performed using this long-wavelength SPOPO source. The ability to tune the excitation wavelength delivered to the sample significantly improved the efficiency of both the 3PLSM and THG imaging experiments.
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Affiliation(s)
- G McConnell
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow, G4 0NR, UK.
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12
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Abstract
In the last decade, fluorescence resonance energy transfer (FRET) has become a useful technique for studying intermolecular interactions applied to the analysis of biological systems. Although FRET measurements may be very helpful in the comprehension of different cellular processes, it can be difficult to obtain quantitative results, hence the necessity of studying FRET on controllable systems. Here, a fuzzy nanostructured system called a nanocapsule is presented as a nanometric-device allowing distance modulation, thus preserving photophysical properties of fluorescent dyes and exhibiting good potential features for improving quantitative FRET analysis. We evaluated the behavior of such a sample using four FRET methods (three of them based on steady-state fluorescence and one using lifetime measurements). Within some limitations that can be overcome, these nanodevices have the potential to serve as a benchmark system for characterizing new FRET couples and to develop quantitative approaches for FRET analysis.
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Affiliation(s)
- V Caorsi
- LAMBS, MicroScoBIO Research Center, Department of Physics (DIFI), University of Genoa, Genoa, Italy.
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13
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Abstract
More than a threefold increase in multiphoton laser scanning microscopy depth penetration using a passive predispersion compensation system is reported. Using dispersion-controlled pulses to counteract the effects of positive group delay dispersion in the imaging platform, optical sectioning of fluorescent samples to depths in excess of 800 microm was observed, compared with only 240 microm using a noncompensated setup. Experimental results obtained from both the predispersion compensated and noncompensated systems are compared with theoretical values of pulse broadening in a laser scanning microscope. The observed improvement in depth profiling potentially widens the applications and user base of nonlinear microscopy techniques.
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MESH Headings
- Anatomy, Cross-Sectional/instrumentation
- Anatomy, Cross-Sectional/methods
- Image Enhancement/methods
- Imaging, Three-Dimensional/methods
- Microscopy, Confocal/instrumentation
- Microscopy, Confocal/methods
- Microscopy, Fluorescence, Multiphoton/instrumentation
- Microscopy, Fluorescence, Multiphoton/methods
- Phantoms, Imaging
- Reproducibility of Results
- Sensitivity and Specificity
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Affiliation(s)
- G McConnell
- Strathclyde Institute for Pharmacy and Biomedical Sciences, Centre for Biophotonics, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, United Kingdom.
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14
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Marsh E, Francis M, McConnell G, Quinn P, Chung K, Paulson R, Jain J. O-12. Fertil Steril 2006. [DOI: 10.1016/j.fertnstert.2006.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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16
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Abstract
The illumination source for all high-resolution, optical sectioning, scanning microscopes is crucially important to the overall performance of the system. We examine advances that have been made in laser sources for both confocal and multiphoton microscopy where the emphasis has been on the development of potentially low-cost, easy to use sources. Growing interest in temporally and spatially resolved techniques has directed laser research towards addressing these challenges. We present the most recent developments in sources for confocal and multiphoton microscopy along with the considerations that should be made when a new source is being considered.
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Affiliation(s)
- J M Girkin
- Institute of Photonics, Wolfson Centre, University of Strathclyde, Glasgow, G4 0NW, United Kingdom.
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17
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Girkin JM, Gu E, Griffin C, Choi HW, Dawson MD, McConnell G. Use of confocal and multiphoton microscopy for the evaluation of micro-optical components and emitters. Microsc Res Tech 2004; 64:293-6. [PMID: 15481047 DOI: 10.1002/jemt.20085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We report on the application of confocal and multiphoton microscopic techniques for the evaluation of the latest generation of micro optical components. The optical emitting characteristics of arrays of matrix addressable GaN micrometer-sized light emitting diodes (micro-LEDs) have been measured using a commercial confocal microscope utilising the LEDs' own emission along with reflection confocal microscopy to determine the surface structure. Multiphoton induced luminescence from the 10-20-micron diameter emitters has also been used to examine the structure of the device and we compare this with electrically induced emission. In related work, the optical properties of micro lens arrays (10-100-micron diameter) fabricated in SiC, Sapphire, and Diamond have been determined using transmission confocal microscopy. Such optical microscopy techniques offer a simple, non-destructive method to determine the structure and performance of such novel devices.
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Affiliation(s)
- J M Girkin
- Institute of Photonics, Wolfson Centre, University of Strathclyde, Glasgow, G4 0NW, United Kingdom.
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18
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McConnell G, Smith GL, Girkin JM, Gurney AM, Ferguson AI. Two-photon microscopy of fura-2-loaded cardiac myocytes with an all-solid-state tunable and visible femtosecond laser source. Opt Lett 2003; 28:1742-4. [PMID: 14514086 DOI: 10.1364/ol.28.001742] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report a robust and reliable platform source for visible-wavelength multiphoton microscopy that is based on nonlinear optical methods. We demonstrate a synchronously pumped, singly resonant optical parametric oscillator with simultaneous intracavity third-order quasi-phase matching in a single crystal that generates continuously tunable, visible, and femtosecond-pulsed radiation. The application of the system is demonstrated by two-photon laser-scanning fluorescence microscopy of rabbit cardiac myocytes loaded with the fluorescent Ca2+ indicator fura-2.
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Affiliation(s)
- G McConnell
- Centre for Biophotonics, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, Scotland, UK.
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19
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Graf T, McConnell G, Ferguson AI, Bente E, Burns D, Dawson MD. Synchronously pumped optical parametric oscillation in periodically poled lithium niobate with 1-w average output power. Appl Opt 1999; 38:3324-3328. [PMID: 18319928 DOI: 10.1364/ao.38.003324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report on a rugged all-solid-state laser source of near-IR radiation in the range of 1461-1601 nm based on a high-power Nd:YVO(4) laser that is mode locked by a semiconductor saturable Bragg reflector as the pump source of a synchronously pumped optical parametric oscillator with a periodically poled lithium niobate crystal. The system produces 34-ps pulses with a high repetition rate of 235 MHz and an average output power of 1 W. The relatively long pulses lead to wide cavity detuning tolerances. The comparatively narrow spectral bandwidth of <15 GHz is suitable for applications such as pollutant detection.
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Affiliation(s)
- T Graf
- Department of Physics and Applied Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG, United Kingdom.
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Israel D, McConnell G. New law protects older workers. HRMAGAZINE 1991; 36:77-8. [PMID: 10110339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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McConnell G. Integrated hospital budgeting--a summary. Hosp Trustee 1983; 7:10-1. [PMID: 10298796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Morgan LM, McConnell G, Chandler E, Welshman SG. Introduction of computer facilities to a clinical chemistry laboratory. Ann Clin Biochem 1980; 17:47-52. [PMID: 7377744 DOI: 10.1177/000456328001700109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A clinical chemistry laboratory information system based on MUMPS is described, together with the problems associated with its implementation. Tabular displays and cusum charts as well as cumulative records are available on a real-time basis. Data capture is by both on-line and off-line techniques. After 18 months' live running the management of information within the laboratory has been significantly improved.
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McConnell G, Nichols PD. The facsimile solution... Health Care Can 1979; 21:23-4. [PMID: 10241326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Abstract
A range of chlorinated hydrocarbons derived from C
1
and C
2
hydrocarbons is manufactured industrially. They are used as intermediates for further chemical manufacture and also outside the chemical industry as solvents or carriers. In the latter category losses in use are eventually dispersed to the environment. The distribution of some of these compounds, including chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene and trichloroethane, in the environment (air, water and marine sediments) has been investigated and the results are presented. The concentrations found have been compared with acute toxicity levels to fish and other aquatic organisms, ascertained by laboratory bioassay. The occurrence of the compounds has been determined in a number of marine organisms, especially those at higher trophic levels, and the accumulation of some of them has been investigated in the laboratory. Chemical and microbial degradation processes have been studied in the laboratory to help determine the course of their removal from the aqueous and aerial environment, and the half lives of some of the compounds have been estimated. It is concluded that these compounds are not persistent in the environment, and that there is no significant bioaccumulation in marine food chains.
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Zook BC, McConnell G, Gilmore CE. Basophilic stippling of erythrocytes in dogs with special reference to lead poisoning. J Am Vet Med Assoc 1970; 157:2092-9. [PMID: 4098240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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McConnell G, Lang A. Russell's Fuchsin Bodies. J Med Res 1921; 42:99-103. [PMID: 19972536 PMCID: PMC2121308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McFarland J, McConnell G. A Group of Mice with exceptional Resistance to Mouse Carcinoma. J Med Res 1913; 27:437-444.1. [PMID: 19972093 PMCID: PMC2099716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McConnell G. Carcinoma of the Breast in a Male. J Med Res 1910; 22:145-152.1. [PMID: 19971936 PMCID: PMC2098939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McConnell G. A mucin-containing multilocular Cyst of the Ovary. J Med Res 1909; 20:105-112. [PMID: 19971875 PMCID: PMC2099359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McConnell G. Recurrent Liposarcoma of the Kidney. J Med Res 1908; 19:225-236.1. [PMID: 19971857 PMCID: PMC2099347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McConnell G. Epidermal Fibrils in the Classification of malignant growths. J Med Res 1908; 19:67-71. [PMID: 19971853 PMCID: PMC2100010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McConnell G. Sudan Oil in the Transplantation of tumors. J Med Res 1908; 18:381-383. [PMID: 19971831 PMCID: PMC2099978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McConnell G. A Case of Multiple Primary Carcinoma. J Med Res 1907; 16:483-494.1. [PMID: 19971778 PMCID: PMC2099849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McConnell G. The Elastic Tissue of Carcinomata. J Med Res 1907; 16:7-16.1. [PMID: 19971756 PMCID: PMC2099835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McFarland J, McConnell G. Histologic studies of Xanthoma. J Med Res 1904; 12:69-74.1. [PMID: 19971628 PMCID: PMC2099874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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