Interfaces Newsletter September 2020

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Welcome to Interfaces, the newsletter from the Department of Materials Science and Engineering at the University of Sheffield. Every month, we’ll bring you news from the world of Materials, from us and elsewhere, and how discoveries made through the years affect our lives today.

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Welcome Back

As the new academic year starts, Head of Department, Professor John Haycock welcomes students and staff back to the Department.

We are very pleased to welcome our students back this week to lectures, practical classes and tutorials, but of course this year, university life will be somewhat different.  

As with all higher education institutions around the world, we have had to make significant changes to the way we deliver our courses. We will endeavour to provide face-to-face sessions for the practical elements of the course, and personal contact for tutorials, while it is considered safe to do so.  Lectures will be online, but importantly, there will be the opportunity to engage with the lecturers live. 

Clearly this will be a different experience for our students and staff. While we navigate through the present challenges, we will continually strive to ensure that we:

  • prioritise safety both on and off campus
  • provide engaging, inspiring and supportive learning
  • create opportunities for students to socialise, meet people and try out new experiences
  • welcome students into a supportive, collegial community where nothing is more important than their education and wellbeing

Over the summer we have been adapting our research activities by enabling our researchers to return to campus safely, so that we can continue to perform world-leading research, and collaborate with industry and other academics.

Yes, things are different, and we don’t know how the external environment will change over the coming weeks and months, but I wanted to let you know that we are doing what we can to adapt to the ever changing situation, and remain positive that we will continue to provide the very highest standards across teaching and research.

Professor John W Haycock

Head of Department, Materials Science and Engineering


Lab-grown bone could change the way we test new medical treatments

A new technology that could be used to test new treatments for human organs and bone tissue – all whilst reducing the need for animal research – has been developed by engineers at the University of Sheffield.

The study, led by researchers from the University’s Department of Materials Science and Engineering and the Insigneo Institute for in silico Medicine, along with collaborators from Universitat Ramon Llull, Spain, developed a bone-on-a-chip device containing mini scaffolding that can be used to grow human bone tissue in the laboratory.

In a new paper published in Frontiers in Bioengineering and Biotechnology, the researchers demonstrate how the bone-on-a-chip – a tiny chip containing living cells – can be used to grow bone tissue which can then be used to test new potential treatments for diseased or damaged bones.

Testing new medicines usually requires extensive in vivo testing involving animal models. However, the new approach developed by the University of Sheffield-led team has been developed in vitro – entirely in the laboratory – and reduces the need to use animals in research.

The field of organ-on-a-chip aims to create small devices that contain miniature versions of organs such as bone, liver or lungs in the laboratory. By testing new medicines on small versions of human organs rather than in animal models, the hope is that there will be a higher success rate of finding ones that work in humans.

The aim is that one day, the device developed by the Sheffield team could be connected to other organ-on-a-chip devices – such as the liver, heart, lungs, etc – to create a human-on-a-chip that would remove the need for animal research in the development of new medical treatments entirely.

In vitro testing of new treatments is normally done on cells grown on flat, two-dimensional surfaces. However, the team of researchers has created three-dimensional scaffold structures within their bone-on-a-chip that better resembles real bone.

The three-dimensional structures are developed using a material known as a polymerised high internal phase emulsion (polyHIPE) using a technique called emulsion templating. An emulsion is a mixture of oil and water which doesn’t separate – like mayonnaise or milk. A polyHIPE is made using an oil that solidifies under ultraviolet light to create a plastic material which contains millions of tiny interconnected holes where the water used to be. These highly porous materials form a scaffold that helps cells create new bone tissue in 3D.

Having produced the three dimensional scaffolds, the team inserted them into a mini bioreactor to create the bone-on-a-chip device and used in vitro techniques to assess its potential to reproducibly grow human bone tissue from stem cells.

In the new paper, the researchers present findings demonstrating that organ-on-a-chip technologies have the potential to revolutionise pharmaceutical pre-clinical testing by increasing throughput whilst minimising financial and ethical concerns associated with animal research.

Dr Frederik Claeyssens, Reader in Biomaterials from the University of Sheffield’s Department of Materials Science and Engineering, said: “The introduction of microfluidic channels in a porous material allows us to mimic the natural 3D environment of cells better than in standard microfluidics.

“This is, in my view, a great enabling technology to build complex 3D tissues – or organs-on-a-chip – as testing platforms for pharmaceutical testing.

“These platforms have the potential to reduce the time and effort required for, and also reduce the use of animal models for preclinical drug testing.”

To access the paper, visit: https://doi.org/10.3389/fbioe.2020.557111


RILEM Week goes virtual

2020 was supposed to be the year that the University of Sheffield welcomed delegates from across the world for the 74th RILEM Annual Week and 40th Cement and Concrete Science Conference, but Coronavirus put paid to that.

One of the virtual reality poster displays at the Cement and Concrete Science Conference.

Instead, the decision was made for the University of Sheffield to host the conference virtually so that researchers could still share their work, and the latest developments could be shared, as they would have been at a physical conference. An extended deadline for abstract submissions for poster presentations, along with an opportunity for researchers to deliver 4 minute ‘flash’ presentations, meant that those who were unable to physically attend the event could still present their work.

Across the 3-day Cement and Concrete Science and RILEM Week Conference, a total of 91 flash presentations, 127 oral presentations and 11 plenary and keynote talks were delivered, alongside the RILEM week activities of standing committees, technical committees and journal management meetings.

The 320 registered delegates, from time zones as diverse as New Zealand (GMT+12) and Oregon, USA (GMT-7) had access to five parallel conference sessions, together with poster sessions and networking rooms. By using pre-recorded talks, any potential issues with internet connections were avoided, as well as mitigating any issues with extreme time zone differences.

The organisers embraced the virtual aspect of the conference to provide virtual reality rooms for displaying and discussing poster presentations and networking opportunities, and worked hard to make access to all the online sessions simple and easy to navigate by providing user guides tailored to the sessions we were hosting.

Dr Sarah Kearney’s poster display

The sessions themselves were hosted from a socially-distanced technical hub (known for the week as the “nerve centre”) located onsite at the University of Sheffield, where the staff of 3 managed the operation of the parallel sessions, poster rooms and networking spaces.

Professor John Provis, Professor of Cement Materials Science and Engineering in the Department of Materials Science and Engineering at the University of Sheffield and RILEM Honorary President 2019-20, commented, “Changing the way the conference was delivered this year was challenging, and the efforts of the local organising committee – Dan Geddes, Sam Ghazizadeh, Sarah Kearney and Antonia Yorkshire – must be recognised. Their work, with the support of the rest of the Cements@Sheffield team, helped the event to be a huge success, and we’re really proud of how well the event functioned.”

Dr Sarah Kearney added, “Feedback from attendees has been really positive, and we hope that all the attendees enjoyed the week and found the event informative and interesting. We’d like to thank the presenting authors, sessions chairs, and delegates for contributing and attending.”

The Sheffield team are now sharing their experience of online conference planning with the team in Mexico who are hosting the 75th RILEM Week in 2021. Whether the 2021 event also needs to run in an online format remains to be seen, but our experience this year shows that success can be pulled from the jaws of disaster, whatever is thrown at us!


Understanding the atomic effect of magnetic interactions in perovskite materials

New research from the University of Sheffield has advanced the understanding of the atomic structure of materials which will be critical in the progress of future computing applications, such as spintronic and quantum computing.

Magnetic structures in double perovskites. (a) Type I antiferromagnetic structure. (b) Type II antiferromagnetic structure. Edited and reproduced from DOI 10.1021/acs.chemmater.0c02971

Perovskites are a class of compounds which have the same crystal structure as calcium titanate, in which different cations can be embedded, imparting properties such as superconductivity, magnetoresistance, ionic conductivity, and a multitude of dielectric properties, leading to the development of diverse engineering materials.

In this research, scientists from the Department of Materials Science and Engineering were studying the magnetic interactions within the structure of the double perovskite crystals found in a compound made up of barium, manganese, tungsten and oxygen containing either tellurium or tungsten ions to see how the configuration of the electrons in the ions could affect the magnetic structure of the overall material.

By using a range of investigative techniques available at the ISIS Neutron and Muon Source in Oxfordshire, including neutron diffraction, inelastic neutron scattering, muon spectroscopy and magnetic susceptibility, the research group led by Dr Eddie Cussen built up a comprehensive picture of the structure and magnetic behaviour of these materials. They found that although the two materials Ba2MnTeO6 and Ba2MnWO6 are isostructural, and have almost identical structures, exchanging the tellurium ion for tungsten has a dramatic effect on the magnetic behaviour. This comes down to their positions in the periodic table. As tellurium is in group 16, in its Te6+ form it has ten electrons occupying its outer d-orbitals, and can therefore be described as d10. Tungsten, however, is in group 6, leading to its W6+ form taking the configuration d0.

Dr Cussen comments, “We used the advanced diffraction facilities at ISIS to establish that the same crystal symmetry exists in the magnetic systems for two perovskite materials. This geometrically cancelled out many of the stronger magnetic effects and allowed the impact of the empty or full d orbitals of Te and W to take centre stage and ‘choose’ the most stable magnetic structure.”

The researchers found that, in Ba2MnTeO6 at low temperature, the manganese ions (Mn2+) are arranged in a cubic structure, forming a Type I magnetic structure. Above 20 K, the group’s inelastic neutron scattering and muon spectroscopy experiments showed that the material undergoes a transition to form a short-range correlated magnetic state similar to that seen in MnO. ​

However, when studying Ba2MnWO6, they found that it takes the Type II structure. This is likely to be because the empty d orbitals on the W6+ ion can interact with the orbitals on the oxygen ions, creating a mechanism for extending superexchange through the structure and allowing magnetic interactions between next-nearest Mn2+ cations to dominate. Inelastic neutron scattering was used to determine the magnetic interactions in the materials.

The group’s studies not only inform the study of these perovskites, but the influence of the empty d orbitals could also be occurring in other magnetic systems, says Dr Cussen; “Many electronic applications such as sensing, data storage and information processing rely on exploiting transitions between states. The facilities at ISIS have allowed us to quantify the impact of chemical control arising from non-magnetic ions. We can use this as a tool to tweak materials composition so that they lie on the cusp of transition and may be switchable into new states.”

He adds; “This work relies on materials synthesis, crystal structure measurements, heat capacity, magnetometry as well as multiple neutron scattering and muon relaxation measurements. The facilities at ISIS are key to the experiments and this work relied on a diverse team. The resources provided at ISIS: neutrons, muons and the materials characterisation lab, are key to almost every aspect of the work.”

The details of the research can be found in:

Physical Review Materials characterising Ba2MnWO6, available at DOI: 10.1103/PhysRevMaterials.4.014408

Chemistry of Materials characterising Ba2MnTeO6, available at DOI: 10.1021/acs.chemmater.0c02971​

Article adapted from https://www.isis.stfc.ac.uk/Pages/SH20_dorbital_occupation.aspx, acknowledging the work of Rosie de Laune


University of Sheffield researcher honoured with Doctoral Researcher Award

Biomaterials researcher, Dr Betül Aldemir Dikici recently won first place in the Engineering Sciences category of the Doctoral Researcher Awards for her research into development of multiscale porous, osteogenic and angiogenic bone tissue scaffolds.

Betül Aldemir Dikici at work in the lab

Dr Betül Aldemir Dikici from the University’s Department of Materials Science and Engineering has been awarded Doctoral Researcher Award (DRA2020 – http://drawards.org.uk/) in the category of Engineering Sciences for the recognition of her research on development of multiscale porous, osteogenic and angiogenic bone tissue engineering scaffolds.

DRA is an annual UK-wide academic competition in which junior researchers who are pursuing (or have recently completed) doctoral degrees in the UK present their research to an audience of their peers along with experts in a range of disciplines. The awards, which first took place in 2012, are presented in three main categories: Natural & Life Sciences, Engineering Sciences, and Management & Social Sciences.

In May, candidates were asked to submit their CV, research statements, representative research paper, and project description of their PhD research. In July, five finalists in each category were notified, and invited to participate in the competition final. Since the Covid-19 pandemic prevented the event taking place in a physical location, the finalists were asked to take part virtually, presenting their papers online at the event on 12 September.

Betül presenting to the virtual judging panel

Following her presentation, Betül was awarded the 1st place in the category of Engineering Sciences of DRA2020.

Betül has been working as a PhD student, in the Biomaterials and Tissue Engineering Group of Kroto Research Institute and Insigneo Institute under supervision of Dr Frederik Claeyssens and Prof Gwendolen Reilly, and has recently completed her PhD. Her research has focused on the development of emulsion templated matrices for tissue engineering applications.

In the presented work, both the structural and biochemical requirements for the development of scaffolds for bone regeneration were discussed. Multiscale porous polymeric scaffolds have been fabricated by combining emulsion templating and three-dimensional (3D) printing techniques, taking advantage of the photocurability of the polymer (polycaprolactone synthesised at the University). This research suggests an alternative approach to improve the biological performance of polymeric matrices by the decoration of the scaffolds with bone cell-derived extracellular matrix (ECM) decoration.

In vivo and in vitro evaluations demonstrated that ECM-decorated multiscale porous scaffolds developed in this study appear to have great potential to be used as a bone graft substitute.

This work has recently been published in ACS Applied Materials, and more details of Betül’s research, can be found in the selected papers listed below or on her personal website (https://aldemirbetul.wixsite.com/baldemir).

Selected papers

(1) B. Aldemir Dikici, F. Claeyssens, Basic Principles of Emulsion Templating and Its Use as an Emerging Manufacturing Method of Tissue Engineering Scaffolds, Front. Bioeng. Biotechnol. 8 (2020). doi:10.3389/fbioe.2020.00875.

(2) B. Aldemir Dikici, S. Dikici, G.C. Reilly, S. MacNeil, F. Claeyssens, A Novel Bilayer Polycaprolactone Membrane for Guided Bone Regeneration: Combining Electrospinning and Emulsion Templating, Materials (Basel). 12 (2019) 2643. doi:10.3390/ma12162643.

(3) B.A. Dikici, C. Sherborne, G.C. Reilly, F. Claeyssens, Emulsion templated scaffolds manufactured from photocurable polycaprolactone, Polymer (Guildf). (2019). doi:10.1016/j.polymer.2019.05.023.

(4) S. Dikici, B. Aldemir Dikici, S.I. Bhaloo, M. Balcells, E.R. Edelman, S. MacNeil, G.C. Reilly, C. Sherborne, F. Claeyssens, Assessment of the Angiogenic Potential of 2-Deoxy-D-Ribose Using a Novel in vitro 3D Dynamic Model in Comparison With Established in vitro Assays, Front. Bioeng. Biotechnol. 7 (2020). doi:10.3389/fbioe.2019.00451.

(5) B. Aldemir Dikici, G.C. Reilly, F. Claeyssens, Boosting the osteogenic and angiogenic performance of multiscale porous polycaprolactone scaffolds by in vitro generated extracellular matrix decoration, ACS Appl. Mater. Interfaces. 12 (2020) 12510–12524. doi:10.1021/acsami.9b23100.


Materials A2Z

Have you been keeping track of our ongoing journey through the A to Z Materials Science and Engineering? There’s well-known words on there, as well as some that may be less familiar.

Having been progressing through the alphabet since January, we have reached the letter S. Head over to Twitter, Instagram or Facebook and take a look at what you’ve missed by searching for the hashtags #materialsA2Z and #IAmAMaterialsScientist.

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