Imperial College London

Professor Chris Dunsby

Faculty of Natural SciencesDepartment of Physics

Professor of Biomedical Optics
 
 
 
//

Contact

 

+44 (0)20 7594 7755christopher.dunsby Website

 
 
//

Location

 

622Blackett LaboratorySouth Kensington Campus

//

Summary

 

Publications

Publication Type
Year
to

260 results found

Wysoczanski R, Baker JR, Fenwick P, Alexandrov Y, Dunsby C, French P, Barnes PJ, Donnelly LEet al., 2022, Defective Phagocytosis in COPD Macrophages Is Improved by Mitochondrial Antioxidants Without Alteration in Mitochondrial Function, Publisher: AMER THORACIC SOC, ISSN: 1073-449X

Conference paper

Hong W, Dunsby C, 2022, Automatic tube lens design from stock optics for microscope remote-refocusing systems, Optics Express, Vol: 30, Pages: 4274-4278, ISSN: 1094-4087

The remote-refocusing approach of Botcherby et al. [Opt. Lett. 32, 2007 (2007) [CrossRef] ] has been applied widely to 2D and 3D fluorescence microscopes to enable rapid refocusing of the optical system without mechanically perturbing the sample. In order for this approach to operate correctly, it requires that the overall magnification of the first two microscope systems matches the ratio of the refractive indices in sample and intermedia image spaces. However, commercially available tube lenses are not always suitable to produce the desired overall magnification. Therefore, a practical approach to produce tube lenses with low expense and diffraction-limited performance is required. Tube lenses can be formed using a pair of stock achromatic doublets, however, selecting appropriate pairs of achromatic doublets from stock optics is a time-consuming process, as many combinations can be considered. In this paper, we present two software packages (Catalogue Generator and Doublet Selector) developed in MATLAB that use the application programming interface (ZOS-API) to the Zemax OpticStudio optical design software to realise an automatic search of stock achromatic doublets to produce microscope tube lenses with a specified focal length, entrance pupil diameter and maximum design field angle. An algorithm to optimise principal plane positions in versions of OpticStudio before 20.2 was also introduced to enable the use of older software versions. To evaluate the performance of Catalogue Generator and Doublet Selector, we used them to generate ten tube lens designs. All of the software-produced tube lenses have a better optical performance than those using manually selected pairs of stock doublets lenses.

Journal article

Ramuz M, Diakonov I, Dunsby C, Gorelik Jet al., 2022, MultiFRET: A Detailed Protocol for High-Throughput Multiplexed Ratiometric FRET., Methods Mol Biol, Vol: 2483, Pages: 33-59

The newly generated software plugin MultiFRET allows for real-time measurements of multiplexed fluorescent biosensors in a near high-throughput fashion. Here we describe a detailed protocol for setup and use of this software for any purpose requiring instant feedback during fluorescence measurement experiments. We further describe its non-primary features including beam splitter misalignment correction, custom calculations through input of simple equations typed in a .txt format, customizable Excel output, and offline bulk analysis of image stacks. Finally, we supply a usage example of a cAMP measurement in cultured rat neonatal cardiomyocytes.

Journal article

Wright T, Sparks H, Paterson C, Dunsby Cet al., 2021, Video-rate remote refocusing through continuous oscillation of a membrane deformable mirror, Journal of Physics: Photonics, Vol: 3, Pages: 1-14, ISSN: 2515-7647

This paper presents the use of a deformable mirror (DM) configured to rapidly refocus a microscope employing a highnumerical aperture objective lens. An Alpao DM97-15 membrane DM was used to refocus a 40×/0.80 NA water-immersionobjective through a defocus range of -50 to 50 m at 26.3 sweeps per second. We achieved imaging with a mean Strehlmetric of > 0.6 over a field of view in the sample of 200×200 m2 over a defocus range of 77 m. We describe anoptimisation procedure where the mirror is swept continuously in order to avoid known problems of hysteresis associatedwith the membrane DM employed. This work demonstrates that a DM-based refocusing system could in the future be used inlight-sheet fluorescence microscopes to achieve video-rate volumetric imaging.

Journal article

Kalita R, Flanagan W, Lightley J, Kumar S, Alexandrov Y, Garcia E, Hintze M, Barkoulas M, Dunsby C, French PMWet al., 2021, Single-shot phase contrast microscopy using polarisation-resolved differential phase contrast, JOURNAL OF BIOPHOTONICS, Vol: 14, ISSN: 1864-063X

Journal article

Wysoczanski R, Baker J, Fenwick P, Dunsby C, French P, Barnes P, Donnelly Let al., 2021, Image analysis of tissue macrophages to confirm differential phagocytosis between groups by microscopy and automated bacterial quantification, Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936

Conference paper

Lightley J, Gorlitz F, Kumar S, Kalita R, Kolbeinsson A, Garcia E, Alexandrov Y, Bousgouni V, Wysoczanski R, Barnes P, Donnelly L, Bakal C, Dunsby C, Neil MAA, Flaxman S, French PMWet al., 2021, Robust deep learning optical autofocus system applied to automated multiwell plate single molecule localization microscopy, JOURNAL OF MICROSCOPY, ISSN: 0022-2720

Journal article

Garcia E, Lightley J, Kumar S, Kalita R, Gorlitz F, Alexandrov Y, Cook T, Dunsby C, Neil M, Roufosse C, French Pet al., 2021, Application of direct stochastic optical reconstruction microscopy (dSTORM) to the histological analysis of human glomerular disease, Publisher: SPRINGER, Pages: S142-S142, ISSN: 0945-6317

Conference paper

Garcia E, Lightley J, Kumar S, Kalita R, Gorlitz F, Alexandrov Y, Cook T, Dunsby C, Neil MAA, Roufosse CA, French PMWet al., 2021, Application of direct stochastic optical reconstruction microscopy (dSTORM) to the histological analysis of human glomerular disease, JOURNAL OF PATHOLOGY CLINICAL RESEARCH, Vol: 7, Pages: 438-445

Journal article

Cannon T, Lagarto J, Dyer B, Garcia Castano E, Kelly D, Peters N, Lyon A, French P, Dunsby Cet al., 2021, Characterisation of NADH fluorescence properties under one-photon excitation with respect to temperature, pH and binding to lactate dehydrogenase, Optical Society of America Continuum, Vol: 4, Pages: 1610-1625

Reduced nicotinamide adenine dinucleotide (NADH) is the principal electron donor in glycolysis and oxidative metabolism and is thus recognized as a key biomarker for probing metabolic state. While the fluorescence characteristics of NADH have been investigated extensively, there are discrepancies in the published data due to diverse experimental conditions, instrumentation and microenvironmental parameters that can affect NADH fluorescence. Using a cuvette-based time-resolved spectrofluorimeter employing one-photon excitation at 375 nm, we characterized the fluorescence intensity, lifetime, spectral response, anisotropy and time-resolved anisotropy of NADH in aqueous solution under varying microenvironmental conditions, namely temperature, pH, and binding to lactate dehydrogenase (LDH). Our results demonstrate how temperature, pH, and binding partners each impact the fluorescence signature of NADH and highlight the complexity of the fluorescence data when different parameters produce competing effects. We hope that the data presented in this study will provide a reference for potential sources of variation in experiments measuring NADH fluorescence.

Journal article

Dvinskikh L, Harding S, Sparks H, Gorelik J, MacLeod K, Dunsby Cet al., 2021, High speed imaging of calcium dynamics in cardiomyocytes with a flexible light-sheet fluorescence microscope, Biophotonics Congress 2021

Conference paper

Kondo H, Ratcliffe CDH, Hooper S, Ellis J, MacRae J, Hennequart M, Dunsby CW, Anderson K, Sahai Eet al., 2021, Single-cell resolved imaging reveals intra-tumor heterogeneity in glycolysis, transitions between metabolic states, and their regulatory mechanisms, CELL REPORTS, Vol: 34, ISSN: 2211-1247

Journal article

Jones DC, Alexandrov Y, Curry N, Kumar S, Lanigan PMP, McGuinness CD, Dale MW, Twitchen DJ, Fisher D, Neil MAA, Dunsby C, French PMWet al., 2021, Multidimensional spectroscopy and imaging of defects in synthetic diamond: excitation-emission-lifetime luminescence measurements with multiexponential fitting and phasor analysis, Journal of Physics D: Applied Physics, Vol: 54, Pages: 1-13, ISSN: 0022-3727

We report the application of phasor analysis and nonlinear iterative fitting to complex spatial and spectroscopic luminescence decay data obtained from multidimensional microscopy of a CVD diamond grown on a HPHT substrate. This spectral and lifetime-resolved analysis enabled spatial mapping of variations in concentrations of nitrogen vacancy (NV) defects in both charge states and the quenching of NV− defects, as well as the identification of SiV− luminescence. These imaging and spectroscopic modalities may be important for reliable fabrication of quantum devices based on such defects in diamond, which will require well-defined and characterised quantum electronic properties.

Journal article

Lightley J, Görlitz F, Kumar S, Kalita R, Kolbeinsson A, Garcia E, Alexandrov Y, Bousgouni V, Wysoczanski R, Barnes P, Donelly L, Bakal C, Dunsby C, Neil MAA, Flaxman S, French PMWet al., 2021, ROBUST OPTICAL AUTOFOCUS SYSTEM UTILIZING NEURAL NETWORKS APPLIED TO AUTOMATED MULTIWELL PLATE STORM MICROSCOPY, ISSN: 1605-7422

We present a robust, low-cost neural network-based optical autofocus system that can operate over a range of ±100µm with submicron precision, enabling automated high-content super-resolved imaging with a 1.3 NA objective lens.

Conference paper

Sparks H, Almagro J, Behrens A, Salbreux G, Dunsby Cet al., 2021, Dual-view oblique plane microscopy

Dual-view Oblique Plane Microscopy (dOPM) enables single-objective multi-view light-sheet fluorescence microscopy. This talk introduces the dOPM concept and demonstrates optical resolution performance with exemplar 3D datasets of fluorescence bead samples and fixed multicellular spheroids.

Conference paper

Lightley J, Gorlitz F, Kumar S, Kalita R, Kolbeinsson A, Garcia E, Alexandrov Y, Bousgouni V, Wysoczanski R, Barnes P, Donelly L, Bakal C, Dunsby C, Neil MAA, Flaxman S, French PMWet al., 2021, ROBUST OPTICAL AUTOFOCUS SYSTEM UTILIZING NEURAL NETWORKS APPLIED TO AUTOMATED MULTIWELL PLATE STORM MICROSCOPY, European Conferences on Biomedical Optics - Advances in Microscopic Imaging III, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Kalita R, Lightley J, Kumar S, Alexandrov Y, Garcia E, Flanagan W, Neil MAA, Dunsby C, French PMWet al., 2021, Single-shot quantitative phase contrast using polarisation-resolved differential phase microscopy, European Conferences on Biomedical Optics - Advances in Microscopic Imaging III, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Kalita R, Lightley J, Kumar S, Alexandrov Y, Garcia E, Flanagan W, Neil MAA, Dunsby C, French PMWet al., 2021, Single-shot quantitative phase contrast using polarisation-resolved differential phase microscopy, ISSN: 1605-7422

We present a robust, low-cost single-shot implementation of differential phase microscopy utilising a polarisation-sensitive camera to simultaneously acquire 4 images from which the phase gradients and quantitative phase image can be calculated.

Conference paper

Jones B, McGlone ER, Fang Z, Pickford P, Corrêa IR, Oishi A, Jockers R, Inoue A, Kumar S, Görlitz F, Dunsby C, French PMW, Rutter GA, Tan TM, Tomas A, Bloom SRet al., 2021, Genetic and biased agonist-mediated reductions in β-arrestin recruitment prolong cAMP signalling at glucagon family receptors, Journal of Biological Chemistry, Vol: 296, Pages: 1-15, ISSN: 0021-9258

Receptors for the peptide hormones glucagon-like peptide-1 (GLP-1R), glucose-dependent insulinotropic polypeptide (GIPR) and glucagon (GCGR) are important regulators of insulin secretion and energy metabolism. GLP-1R agonists have been successfully deployed for the treatment of type 2 diabetes, but it has been suggested that their efficacy is limited by target receptor desensitisation and downregulation due to recruitment of β-arrestins. Indeed, recently described GLP-1R agonists with reduced β-arrestin-2 recruitment have delivered promising results in preclinical and clinical studies. We therefore aimed to determine if the same phenomenon could apply to the closely related GIPR and GCGR. In HEK293 cells depleted of both β-arrestin isoforms the duration of G protein-dependent cAMP/PKA signalling was increased in response to the endogenous ligand for each receptor. Moreover, in wild-type cells, “biased” GLP-1, GCG and GIP analogues with selective reductions in β-arrestin-2 recruitment led to reduced receptor endocytosis and increased insulin secretion over a prolonged stimulation period, although the latter effect was only seen at high agonist concentrations. Biased GCG analogues increased the duration of cAMP signalling, but this did not lead to increased glucose output from hepatocytes. Our study provides a rationale for development of GLP-1R, GIPR and GCGR agonists with reduced β-arrestin recruitment, but further work is needed to maximally exploit this strategy for therapeutic purposes.

Journal article

Sparks H, Dent L, Bakal C, Behrens A, Salbreux G, Dunsby Cet al., 2020, Dual-view oblique plane microscopy (dOPM), Biomedical Optics Express, Vol: 11, Pages: 7204-7220, ISSN: 2156-7085

We present a new folded dual-view oblique plane microscopy (OPM) techniquetermed dOPM that enables two orthogonal views of the sample to be obtained by translating apair of tilted mirrors in refocussing space. Using a water immersion 40× 1.15 NA primaryobjective, deconvolved image volumes of 200 nm beads were measured to have full width athalf maxima (FWHM) of 0.35±0.04 μm and 0.39±0.02 μm laterally and 0.81±0.07 μm axially.The measured z-sectioning value was 1.33±0.45 μm using light-sheet FWHM in the frames ofthe two views of 4.99±0.58 μm and 4.89±0.63 μm. To qualitatively demonstrate that the systemcan reduce shadow artefacts while providing a more isotropic resolution, a multi-cellularspheroid approximately 100 μm in diameter was imaged.

Journal article

Wysoczanski R, Baker JR, Fenwick P, Garcia E, Kumar S, Neil MAA, Dunsby C, French PMW, Barnes PJ, Donnelly LEet al., 2020, Analysis of defective phagocytosis in COPD using super-resolution microscopy and automated bacterial quantification, Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936

Conference paper

Sparks H, Dvinskikh L, Firth J, Francis A, Harding S, Paterson C, MacLeod K, Dunsby Cet al., 2020, Development a flexible light-sheet fluorescence microscope for high-speed 3D imaging of calcium dynamics and 3D imaging of cellular microstructure, Journal of Biophotonics, Vol: 13, ISSN: 1864-063X

We report a flexible light‐sheet fluorescence microscope (LSFM) designed for studying dynamic events in cardiac tissue at high speed in 3D and the correlation of these events to cell microstructure. The system employs two illumination‐detection modes: the first uses angle‐dithering of a Gaussian light sheet combined with remote refocusing of the detection plane for video‐rate volumetric imaging; the second combines digitally‐scanned light‐sheet illumination with an axially‐swept light‐sheet waist and stage‐scanned acquisition for improved axial resolution compared to the first mode. We present a characterisation of the spatial resolution of the system in both modes. The first illumination‐detection mode achieves dual spectral‐channel imaging at 25 volumes per second with 1024 × 200 × 50 voxel volumes and is demonstrated by time‐lapse imaging of calcium dynamics in a live cardiomyocyte. The second illumination‐detection mode is demonstrated through the acquisition of a higher spatial resolution structural map of the t‐tubule network in a fixed cardiomyocyte cell.

Journal article

Fang Z, Chen S, Pickford P, Broichhagen J, Hodson DJ, Corrêa IR, Kumar S, Görlitz F, Dunsby C, French PMW, Rutter GA, Tan T, Bloom SR, Tomas A, Jones Bet al., 2020, The influence of peptide context on signaling and trafficking of glucagon-like peptide-1 receptor biased agonists, ACS Pharmacology & Translational Science, Vol: 3, Pages: 345-360, ISSN: 2575-9108

Signal bias and membrane trafficking have recently emerged as important considerations in the therapeutic targeting of the glucagon-like peptide-1 receptor (GLP-1R) in type 2 diabetes and obesity. In the present study, we have evaluated a peptide series with varying sequence homology between native GLP-1 and exendin-4, the archetypal ligands on which approved GLP-1R agonists are based. We find notable differences in agonist-mediated cyclic AMP signaling, recruitment of β-arrestins, endocytosis, and recycling, dependent both on the introduction of a His → Phe switch at position 1 and the specific midpeptide helical regions and C-termini of the two agonists. These observations were linked to insulin secretion in a beta cell model and provide insights into how ligand factors influence GLP-1R function at the cellular level.

Journal article

Lagarto JL, Nickdel MB, Kelly DJ, Price A, Nanchahal J, Dunsby C, French P, Itoh Yet al., 2020, Autofluorescence lifetime reports cartilage damage in osteoarthritis, Scientific Reports, Vol: 10, ISSN: 2045-2322

Osteoarthritis (OA) is the most common arthritis and its hallmark is degradation of articular cartilage by proteolytic enzymes leading to loss of joint function. It is challenging to monitor the status of cartilage in vivo and this study explores the use of autofluorescence lifetime (AFL) measurements to provide a label-free optical readout of cartilage degradation that could enable earlier detection and evaluation of potential therapies. We previously reported that treatment of ex vivo porcine cartilage with proteolytic enzymes resulted in decreased AFL. Here we report changes in AFL of ex vivo mouse knee joints, porcine metacarpophalangeal joints, normal human metatarsophalangeal articular tissue and human OA tibial plateau tissues measured with or without treatment using a compact single-point time resolved spectrofluorometer. Our data show that proteolytically damaged areas in porcine metacarpophalangeal joints present a reduced AFL and that inducing aggrecanases in mouse and human joints also significantly reduces AFL. Further, human cartilage from OA patients presents a significantly lower AFL compared to normal human cartilage. Our data suggest that AFL can detect areas of cartilage erosion and may potentially be utilised as a minimally-invasive diagnostic readout for early stage OA in combination with arthroscopy devices.

Journal article

Harput S, Christensen-Jeffries K, Ramalli A, Brown J, Zhu J, Zhang G, Leow C, Toulemond M, Boni E, Tortoli P, Eckersley R, Dunsby C, Tang M-Xet al., 2020, 3-D super-resolution ultrasound imaging with a 2-D sparse array, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol: 67, Pages: 269-277, ISSN: 0885-3010

High-frame-rate 3-D ultrasound imaging technology combined with super-resolution processing method can visualize 3-D microvascular structures by overcoming the diffraction-limited resolution in every spatial direction. However, 3-D super-resolution ultrasound imaging using a full 2-D array requires a system with a large number of independent channels, the design of which might be impractical due to the high cost, complexity, and volume of data produced. In this study, a 2-D sparse array was designed and fabricated with 512 elements chosen from a density-tapered 2-D spiral layout. High-frame-rate volumetric imaging was performed using two synchronized ULA-OP 256 research scanners. Volumetric images were constructed by coherently compounding nine-angle plane waves acquired at a pulse repetition frequency of 4500 Hz. Localization-based 3-D super-resolution images of two touching subwavelength tubes were generated from 6000 volumes acquired in 12 s. Finally, this work demonstrates the feasibility of 3-D super-resolution imaging and super-resolved velocity mapping using a customized 2-D sparse array transducer.

Journal article

Harput S, Toulemonde M, Ramalli A, Christensen-Jeffries K, Boni E, Tortoli P, Dunsby C, Tang M-Xet al., 2020, Quantitative Microvessel Analysis with 3-D Super-Resolution Ultrasound and Velocity Mapping, IEEE International Ultrasonics Symposium (IEEE IUS), Publisher: IEEE, ISSN: 1948-5719

Conference paper

Zhang G, Toulemonde M, Riemer K, Zhu J, Harput S, Christensen-Jeffries K, Zhu Z, Wang B, Leow CH, Weinberg P, Dunsby C, Tang M-Xet al., 2020, Effects of Mechanical Index on Repeated Sparse Activation of Nanodroplets In Vivo, IEEE International Ultrasonics Symposium (IEEE IUS), Publisher: IEEE, ISSN: 1948-5719

Conference paper

Jones DC, Alexandrov Y, Curry N, Kumar S, Lanigan P, McGuinness C, Dale M, Twitchen D, Fisher D, Neil M, Dunsby C, French Pet al., 2020, A multidimensional imaging and spectroscopic microscope

We present a multidimensional luminescence microscope for characterisation of emission from defects in diamond. We have applied the photoluminescence, hyperspectral and time-resolved luminescence imaging capabilities of this novel instrument to natural and synthetic diamonds.

Conference paper

Gorlitz F, Wysoczanski R, Kumar S, Lightley J, Garcia E, Alexandrov Y, Munro I, Johnson S, Kehoe M, Hollick C, Graham J, Donnelly L, Barnes P, Dunsby C, Neil MAA, French PMWet al., 2020, Towards easier, faster super-resolved microscopy, Conference on Single Molecule Spectroscopy and Superresolution Imaging XIII, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Garcia E, Guo W, Kumar S, Gorlitz F, Sparks H, Alexandrov Y, Munro I, Kelly DJ, Warren S, Chennell G, Sardini A, Carling D, Thorpe P, Dunsby C, French PMWet al., 2020, FLIM, FRET and high content analysis, Symposium on Multiphoton Microscopy in the Biomedical Sciences XX held at SPIE BiOS Conference, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: respub-action=search.html&id=00321238&limit=30&person=true