A New Platform for Biomechanical Imaging Based on Brillouin Scattering

Lead Research Organisation: University of Exeter
Department Name: Physics

Abstract

Mechanical changes in body tissues are widely associated with diverse clinical problems including many of the serious complications of diabetes, atherosclerosis and cancer, but their microstructural bases are poorly understood. In large blood vessels, stiffness is linked to increased risk of cardiovascular mortality - although the contribution of the stiffness from individual tissue constituents to this risk is unknown. Understanding the mechanisms linking stiffness to structure is limited by our ability to measure mechanical properties on length-scales which allow the relationships with tissue structure and composition to be established. BLS microscopy has the potential to fill this void, as demonstrated in a recent publication (Palombo, Madami, Stone and Fioretto, Analyst, 2014, 139, 729-733) where mechanical maps of structure and elasticity were generated based on Brillouin peaks corresponding to specific tissue components. New techniques of imaging the chemical composition of cells and tissues are making a major impact in many fields of biology and medicine. This proposal is concerned with the development of Brillouin light scattering (BLS) imaging, a new method for microscopic imaging of mechanical properties. The mechanical properties of the connective tissues, cartilage or blood vessels are central to their physiological function and changes in mechanical function are implicated in diseases ranging from diabetes to osteoarthritis. BLS imaging therefore offers the prospect of directly imaging a functionally important property, both in tissues and single constituents e.g. collagen and elastin fibres, whose biomechanics probed at multiple frequencies are almost completely unexplored, which will open a new window on tissue mechanics and offers the prospect of developing new diagnostic techniques.

The principle of the approach is to detect the change in frequency of inelastically scattered light arising from the generation of sound waves in the sample. Calculation of the speed of the wave provides a measure of the mechanical properties of the material. Preliminary studies have used confocal BLS microscopy to produce Brillouin frequency maps of an epithelial tissue, which can be combined with Raman micro-spectroscopic maps of chemical composition (Palombo et al. Analyst 2014). Complementary studies have investigated Brillouin scattering in collagen and elastin, the fibrous proteins of the extracellular matrix, and their relationships to fibre micromechanics (Palombo et al. J R Soc Interface, asap).

This work provides the basis for the proposed investigations. The methodology will be applicable to many problems of connective tissue physiology and pathology, but the immediate aim will be to investigate the mechanics of extracellular protein fibres - collagens, elastin, proteoglycans - and the effects of physiological and pathological conditions. These changes are widely associated with diverse clinical problems including many of the serious complications of osteoarthritis and diabetes, but their microstructural bases are poorly understood. The project will require construction of a system that will enable biomechanical imaging through Brillouin scattering with a Virtually Imaged Phase Array (VIPA) spectrometer. This will enable us to develop a significantly faster and more versatile technology for the analysis of fibres (and tissues) and to define functionally significant changes which can, in the longer term, become targets for monitoring or therapeutic intervention.

Planned Impact

This proposal will develop novel techniques for mechanical testing and noninvasive mechanical imaging. Our immediate application is to fundamental problems in tissue biomechanics, which will have direct impact on our understanding of ageing and a wide range of diseases. However, in the longer term, the methodology will also be applicable in many areas of materials research and can form the basis of entirely new approaches to clinical diagnosis, which will generate impacts in many areas.
The team will develop an advanced Brillouin imaging microscopy to measure, identify and localise elasticity and composition in biomaterials. We propose studying important, fundamental open-problems related to tissue structure, mechanics and biophysics, for the academic and clinical communities. The programme is focussed at investigating protein fibres of the extracellular matrix and how physiological and pathological changes affect the mechanics at a molecular level. Ultimately, this new analytical tool may replace current techniques based on elastography and ultrasounds and provide a powerful clinical diagnosis of pathology. A pioneering aspect of the project is the application of the new imaging platform to the essential building blocks of biological tissues: the protein fibres of extracellular matrices. Brillouin imaging or mechanical microscopy offers a unique combination of advantages since it is contact-free, enables fast 3D scanning, has mechanical specificity and high spatial resolution, and relies on intrinsic properties of materials. This gives the new method an unprecedented potential for in vivo applications. The outputs of this research will be shared with clinical collaborators leading to improvements in the setup design and operation to realise a clinically viable multimodal device for possible commercial exploitation. Beyond this, efforts will be made to generate wider impact on the society and economy by advancing knowledge and improving healthcare and by exploring other technological applications of the methods. The specific pathways through which this multiple impact will be achieved are described below.

Societal impact: Impact on the society includes advancing knowledge and improving healthcare. Changes in the mechanical properties of the extracellular matrix are implicated in major diseases such as atherosclerosis, arthritis, disc degeneration and many forms of cancer which are enormous burdens to patients; the public health impact shows that atherosclerosis accounts for one in three of all deaths in the developed world, whilst more than one in three people in the UK develops cancer during their life. A better understanding of these mechanical changes and the development of methods of monitoring them will enhance understanding of disease processes and lead to new therapeutic approaches.

Economic impact: Advancing knowledge and improving healthcare through improved understanding of disease and novel imaging tools has a substantial impact on economy as well as people. Noninvasive clinical tests able to give reliable information and to replace current gold-standard techniques will make surgical interventions obsolete and unnecessary, hence greatly reducing the costs.
There is also a ubiquitous need for mechanical analysis in diverse systems e.g. polymers, synthetic metamaterials, auxetic materials and synthetic biomaterials to which our methodology can be applied. There is active and growing research in these fields in Engineering at Exeter and once our instrument is operational we shall engage with these groups to explore such applications.

Publications

10 25 50
 
Description I have set up a new instrument based on Brillouin scattering which detects the micromechanics of biomaterials in a contactless manner. Mechanical properties are relevant to normal tissue function and changes are observed in disease. Brillouin spectroscopy provides a valuable contrast mechanism to detect heterogeneity and degeneration in elasticity of tissues on a micro-scale. I have discovered that there are many variables in setting up the new experiment - it involves selection of appropriate optics and geometries. As not a great deal of experimental details is available in the literature or a consensus has been established in the design of the optimum set-up, I am attempting various strategies for detection of the Brillouin signal in turbid media which, I hope, will prove effective. I am also investigating the origin of the Brillouin signals in the GHz spectral range based on complementary quasistatic stress-strain testing and correlative Raman scattering to assign the scale of measured mechanical properties. This has been recognised as one of the main priorities in the recently established EU-Horizon 2020 COST Action 'BioBrillouin', of which the PI is the Vice-Chair and UK Management Committee representative.
Key findings are now translating in the publication of an opinion review from experts (myself and a few colleagues in the COST network) which will be submitted to Biophysical Journal later this month.
Exploitation Route Others may want to look at the findings generated by this research to set up their own microscope and/or to use the relevant mechanical data (namely the elastic modulus) of protein fibres and connective tissues to conduct a comparative / correlative analysis and/or to develop new theoretical models for describing the multiscale mechanics of natural biopolymers. This might lead to newly designed tissue engineering approaches. The results of this research are now being exploited for an EPSRC Impact Acceleration Account grant in partnership with Unilever (started 1st March 2018) whereby Unilever is the end-user and various samples of interest have been analysed using the new technique.
Sectors Agriculture, Food and Drink,Chemicals,Education,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

URL https://www.osapublishing.org/boe/abstract.cfm?uri=boe-10-3-1329
 
Description The findings on micromechanical properties of protein fibres and connective tissues have attracted the interest of the private sector, including personal care industry, and new collaborations have began to develop. This will form integral part of follow-up grant proposals to continue the work started with this grant (instrument development) to enable a wider impact. It is expected that novel healthcare devices will be based on the developed technology, as already demonstrated in ophthalmology (Intelon spin-out and clinical trials at MIT Hospital). The PI is the Vice-Chair of the Horizon 2020 COST Action 'BioBrillouin' (2017-2021) which brings together researchers, clinicians and industry to further the development and translational aspects of the novel methodology of Brillouin microspectroscopy. Moreover an EPSRC IAA grant have been awarded to develop partnership with Unilever and increase impact of this research. Findings are now being used to support the development of an open-access database of Brillouin spectra from standard biomaterials as a part of a new grant: (PI: Francesca Palombo) COST Innovators Grant "BLiSS-BMD" IG16124, 2021-22, 116,150€ .
First Year Of Impact 2014
Sector Chemicals,Education,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology
Impact Types Cultural,Societal,Economic

 
Description Publication of an opinion review on the progress of Brillouin microscopy in life sciences
Geographic Reach Europe 
Policy Influence Type Membership of a guideline committee
 
Description Training/educational development for postgraduates/research users
Geographic Reach Multiple continents/international 
Policy Influence Type Influenced training of practitioners or researchers
Impact Impact through training/educational developments for postgraduates/research users (including courses and course material) of Brillouin microscopy. This is realised through organisation and delivery of annual Training Schools (since 2017) within the remit of the COST Action BioBrillouin.
URL https://www.biobrillouin.eu
 
Description As co-applicant: COST
Amount € 507,935 (EUR)
Funding ID CA16124 
Organisation European Cooperation in Science and Technology (COST) 
Department COST Action
Sector Public
Country Belgium
Start 03/2017 
End 04/2021
 
Description As co-applicant: UK National Ion Beam Centre facility access
Amount £11,693 (GBP)
Organisation University of Surrey 
Department Ion Beam Centre
Sector Public
Country United Kingdom
Start 02/2017 
End 02/2018
 
Description BLiSS-BMD Brillouin Light Scattering Spectroscopy - BioMaterial Database
Amount € 116,150 (EUR)
Funding ID IG16124 
Organisation Medical University of Vienna 
Sector Academic/University
Country Austria
Start 11/2021 
End 10/2022
 
Description CRUK / EPSRC Multidisciplinary Project Award
Amount £499,876 (GBP)
Funding ID NS/A000063/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2017 
End 09/2021
 
Description Development of advanced optical tools for early detection and diagnosis of oesophageal cancer with high mechanical and chemical specificity
Amount £499,139 (GBP)
Organisation Gloucestershire Hospitals NHS Foundation Trust 
Sector Public
Country United Kingdom
Start 01/2022 
End 12/2025
 
Description EPSRC DTP PhD studentship - University of Exeter College on Engineering, Maths and Physical Sciences
Amount £70,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2016 
End 07/2019
 
Description Exeter Biomaterials Optical Characterisation Suite - EBOC
Amount £632,086 (GBP)
Funding ID EP/V034251/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 11/2020 
End 05/2022
 
Description Raman Nanotheranostics - RaNT - developing the targeted diagnostics and therapeutics of the future by combining light and functionalised nanoparticles
Amount £5,752,646 (GBP)
Funding ID EP/R020965/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2018 
End 12/2022
 
Title Brillouin scattering microscopy 
Description This is a new biophotonics set-up for contactless micro-mechanical imaging of biological samples. 
Type Of Material Technology assay or reagent 
Year Produced 2017 
Provided To Others? Yes  
Impact Testing is underway on a wide range of biological samples. 
 
Title Datasets on hydrogels as tissue models for Brillouin validation and benchmarking 
Description We published Data and deposited raw data within a university repository related to a study of gelatine hydrogels that can provide benchmarking tools for other Brillouin instrument developers and users. The publication in "Data in Brief" also include analysis methods and algorithms developed for this study. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact Not known yet but it is anticipated that the data will be used within our BioBrillouin community for testing and validation. 
 
Title Development of an algorithm for software analysis of Brillouin imaging data 
Description The model was developed with the aid of a software developer (Simon Harding) and is aimed at handling and processing datasets from Brillouin imaging measurements. 
Type Of Material Data analysis technique 
Year Produced 2019 
Provided To Others? Yes  
Impact Impact on practice and recommendations for other developers and users of the technique. 
 
Description Clinical translation of Brillouin microscopy 
Organisation Gloucestershire Hospitals NHS Foundation Trust
Country United Kingdom 
Sector Public 
PI Contribution We are developing Brillouin microscopy in combination with Raman microscopy for application to oesophageal cancer diagnostics
Collaborator Contribution Ethics submission and consent of patients. Collection of biopsy tissues, histopathological analysis and modelling
Impact https://www.cancerresearchuk.org/our-research/researchers/professor-hugh-barr
Start Year 2017
 
Description Development of Brillouin imaging in Biomedical Sciences 
Organisation National Center for Scientific Research (Centre National de la Recherche Scientifique CNRS)
Department IN2P3-Lyon
Country France 
Sector Academic/University 
PI Contribution Participation (by myself and two members of my research team, Dr Noemi Correa PDRA & Michelle Bailey PhD) in a pan-European COST network, which includes standardisation of Brillouin microscopy measurements through a multi-centre study.
Collaborator Contribution Partners in this network have contributed expertise and background in optics, photonics, microscopy and spectroscopy.
Impact Outputs include a range of publications e.g. Elsayad K, Palombo F, Dehoux T, Fioretto D. (2019) Brillouin Light Scattering Microspectroscopy for Biomedical Research and Applications: introduction to feature issue, BIOMEDICAL OPTICS EXPRESS, volume 10, no. 5, pages 2670-2673, DOI:10.1364/BOE.10.002670. Moreover, a range of invited talks at conferences and organisation of conferences/meeting within the network, e.g. 4th BioBrillouin Conference, Exeter, 9-11/09/2020. Additionally, funding applications e.g. https://ec.europa.eu/info/funding-tenders/opportunities/portal/screen/opportunities/topic-details/ict-36-2020. The collaboration is multi-disciplinary and involves Physics, Chemistry, Biology and Medical Sciences.
Start Year 2017
 
Description Development of Brillouin imaging in Biomedical Sciences 
Organisation University of Perugia
Country Italy 
Sector Academic/University 
PI Contribution Participation (by myself and two members of my research team, Dr Noemi Correa PDRA & Michelle Bailey PhD) in a pan-European COST network, which includes standardisation of Brillouin microscopy measurements through a multi-centre study.
Collaborator Contribution Partners in this network have contributed expertise and background in optics, photonics, microscopy and spectroscopy.
Impact Outputs include a range of publications e.g. Elsayad K, Palombo F, Dehoux T, Fioretto D. (2019) Brillouin Light Scattering Microspectroscopy for Biomedical Research and Applications: introduction to feature issue, BIOMEDICAL OPTICS EXPRESS, volume 10, no. 5, pages 2670-2673, DOI:10.1364/BOE.10.002670. Moreover, a range of invited talks at conferences and organisation of conferences/meeting within the network, e.g. 4th BioBrillouin Conference, Exeter, 9-11/09/2020. Additionally, funding applications e.g. https://ec.europa.eu/info/funding-tenders/opportunities/portal/screen/opportunities/topic-details/ict-36-2020. The collaboration is multi-disciplinary and involves Physics, Chemistry, Biology and Medical Sciences.
Start Year 2017
 
Description Development of Brillouin imaging in Biomedical Sciences 
Organisation Vienna Biocenter
Country Austria 
Sector Charity/Non Profit 
PI Contribution Participation (by myself and two members of my research team, Dr Noemi Correa PDRA & Michelle Bailey PhD) in a pan-European COST network, which includes standardisation of Brillouin microscopy measurements through a multi-centre study.
Collaborator Contribution Partners in this network have contributed expertise and background in optics, photonics, microscopy and spectroscopy.
Impact Outputs include a range of publications e.g. Elsayad K, Palombo F, Dehoux T, Fioretto D. (2019) Brillouin Light Scattering Microspectroscopy for Biomedical Research and Applications: introduction to feature issue, BIOMEDICAL OPTICS EXPRESS, volume 10, no. 5, pages 2670-2673, DOI:10.1364/BOE.10.002670. Moreover, a range of invited talks at conferences and organisation of conferences/meeting within the network, e.g. 4th BioBrillouin Conference, Exeter, 9-11/09/2020. Additionally, funding applications e.g. https://ec.europa.eu/info/funding-tenders/opportunities/portal/screen/opportunities/topic-details/ict-36-2020. The collaboration is multi-disciplinary and involves Physics, Chemistry, Biology and Medical Sciences.
Start Year 2017
 
Description Development of Brillouin spectroscopy technique 
Organisation University of Perugia
Department Department of Physics and Geology
Country Italy 
Sector Academic/University 
PI Contribution Bi-lateral contribution to developing a new technique for application to the biomedical sciences
Collaborator Contribution Prof Daniele Fioretto is the named collaborator on this grant and he contributed by exchanging ideas and being a co-author in the resulting publications.
Impact Two articles and one under review so far. This collaboration is multi-disciplinary: PI's discipline is Physical Chemistry, the collaborator's discipline is Soft Matter Physics
Start Year 2015
 
Description Impact and Knowledge Exchange Award 
Organisation Unilever
Department Unilever Research and Development
Country United Kingdom 
Sector Private 
PI Contribution We developed the Brillouin microscope used for testing Unilever's substrates
Collaborator Contribution Unilever provided samples of interest for testing and validation of our technique
Impact We have produced data that have been analysed to inform manufacturing processes in Unilever. We hope to submit publications related to this project. This is a multi-disciplinary collaboration, spanning research areas in biophysics, biochemistry, material and analytical sciences.
Start Year 2018
 
Title Software package described in the publication "Image analysis applied to Brillouin images of tissue-mimicking collagen gelatins" 
Description We developed a method for the automated retrieval of Brillouin line shape parameters from imaging datasets acquired with a dual-stage VIPA Brillouin microscope. We applied this method for the first time to BLS measurements of collagen gelatin hydrogels at different hydration levels and cross-linker concentrations. This work demonstrates that it is possible to obtain the relevant information from Brillouin spectra using software for real-time high-accuracy analysis. 
Type Of Technology Software 
Year Produced 2018 
Impact Versatile tool for real-time high-accuracy readout of Brillouin signals from dual-stage VIPA imaging instruments, with possible extension to single-stage VIPA. We are furthering the software development including various shapes of curve-fitting functions in the algorithm. 
URL https://doi.org/10.1364/BOE.10.001329
 
Description Open Day for Clinicians 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact COST BioBrillouin Open Day for Clinicians, Perugia (Italy), 12-14 Sep 2018. Four clinicians attended for a discussion on the clinical translation of Brillouin within the remit of aortic aneurism. The clinicians were from the Karolinska Institutet University Hospital in Stockholm, Sweden. They provided research questions for us to be addressed using our developed technique, and they reported increased interest in this new method and the potential to detect mechanical degeneration in aortic wall that can inform intervention and treatment.
Year(s) Of Engagement Activity 2018
 
Description School Visit (Sidmouth College) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact My team engaged in three separate workshops / school visits across the South West, as part of an outreach programme of Exeter Science Centre in 2021. Each workshop was attended by around 20 pupils, and sparked questions after the talk and demo, and the school reported increased interest in STEM subjects.
Year(s) Of Engagement Activity 2021