Biography and previous work

Chris joined the department at the start of 2013 and is head of the Natural Materials Group, currently holding an EPSRC Early Career Fellowship. He is also the Chair of RAPS, an organisation for Recent Appointees in Polymer Science. Previously he was at Oxford where he undertook his BA in Biological Sciences, MSc in Integrative Biosciences, D. Phil and later a Fellowship By Examination (a.k.a JRF) whilst working in the Oxford Silk Group.

Chris’ research uses tools developed for the physical sciences to better understand Nature’s materials, from latex to collagen, but with a focus on silk. By investigating unspun silk’s flow properties he has been able to gain unique insights into their biodiversity, structure and evolution. Additionally, this work has made important links between natural and industrial fibre processing which has lead to a fundamentally new way of designing, testing and fabricating bio-inspired materials.

Current work

Today he combines multiple instruments with rheology, from microscopes (confocal) and spectrometers (IR) to synchrotrons (SANS at ISIS and SAXS/WAXS at ESRF) in order to understand exactly how silk proteins arrange themselves into one of Nature’s most impressive materials.

Key Projects

SPICE: Silk Processing In Controlled Environments: investigating the flow properties of silk and its natural processing. EPSRC Early Career Fellowship

SHARD: Silk in High Rate and Research into Damage Tolerance: understanding the biology and application of silks sonic properties and response to high rate impact (with Dr. C. Siviour and Prof. F. Vollrath Oxford) Leverhulme Trust

WISS: Why is Silk Spun? Integrating bio-rheology with advanced spectroscopic techniques: project for building combinatorial tools and training a next generation user of large scale facilities (i.e. ISIS, the ESRF and Diamond) EPSRC

More detailed Track Record / Biography

Dr Chris Holland (male) is a Senior Lecturer in Materials Science and Engineering at the University of Sheffield. His group is a leading authority in the field of silk materials, addressing the fundamental question: “how is silk spun?” In May 2018 he completed an EPSRC Early Career Fellow (SPICE, a > £1M grant) and was the principal co-ordinator of the H2020 FET project FLIPT (a ~€4M grant, 7 partners, 1.4% success rate) which finished in February 2020. Such projects have involved integrating a range of micro/spectroscopic techniques with rheology in order to study structure development as silk proteins are exposed to controlled flow stress fields.

 

Previously studying as a Biologist at Oxford and undertaking his D. Phil in the Oxford Silk Group, he characterised the flow properties of unspun spider and silkworm silk, overcoming several complexities in the manipulation and testing of these materials. His work demonstrated evolutionary convergence in the flow properties of silk feedstocks as well as a surprising similarity to polymer melt flow. The implication of this work is that natural selection has resulted in a singularly efficient way of rapidly processing proteins into high performance fibres, and this solution is not totally unlike our modern-day industrial techniques. Following this and by turning evolutionary constraints into design criteria, he developed spinnability indicators to predict the quality of artificial silks before they are spun. This showed without doubt that our shortcomings can be attributed primarily to feedstock quality which have in turn been used to increase UK competitiveness by leading to a patent (GB0807868.5), and to date support for 2 UK spin-out companies (Orthox Ltd. (2008) and Spintex Engineering Ltd. (2019)) and sale of UK rheometers (Malvern Instruments Ltd.).

 

After establishing the field of silk rheology as both credible and important during his D.Phil, he begun investigating how flow catalyses silks hierarchical structure development through the development of novel combinatorial rheology techniques. This was largely attributable to the academic freedom provided by his election to Prize Fellow at Magdalen College, an open competition post-doctoral Fellowship. During this fellowship he obtained funding for an international collaboration with Georgetown University in the US to study silk fibrillogenesis using confocal microscopy (Holland et al. 2012 Soft Matter and cover) as well as a UK collaboration with Prof. Ryan’s group in Sheffield to investigate the energetic costs of silk fibre formation (Holland et al. 2012 Advanced Materials and frontispiece). The results of these studies have profoundly influenced our approach to, and understanding of, silk processing. His confocal rheology studies demonstrated that native silk feedstocks is able to self assemble into hierarchical structures (nano and microfibrils) through the action of shear alone, when previously chemical modification or crosslinking was thought to play a major role. This means that silk spinning may be far less complex than originally thought. His work on shear induced light polarisation imaging (SIPLI) in Sheffield attributed, for the first time, a quantitative energetic cost to silk fibrillation. This was found to be ten times less than a typical polymer (HDPE) and when temperature is accounted for, the energy savings are a thousand-fold.

 

The quantification of the energetic savings offered by nature stimulated not only an intellectual curiosity in better understanding the processing optimisations Nature employs, but also a practical one. Incorporating a more engineering focus into his research, in 2012 Chris was very fortunate to be awarded an EPSRC Early Career Fellowship to enable him to explore SPICE: Silk Processing In Controlled Environments (EP/K005693/1). This provided him with the resources to move to the Materials Science and Engineering Department at Sheffield University and build his own research group: a team of physical and life scientists with the aim of turning natural processes into engineering applications (www.naturalmaterialsgroup.com). During this 5 year fellowship his group outputted 35 publications, helped establish a start-up company and participated in 90+ engagement activities, thus generating positive academic, industrial and societal impact (see researchfish outputs).

 

Research highlights during this time were the development of a fundamental set of silk rheological properties in part to be used in simulation which was used to show that silk is spun via pultrusion not extrusion (Sparkes and Holland, 2017, Nature Communications) and in current modelling efforts (collaboration with Prof. McLeish as part of his Advanced Fellowship EP/N031431/2). Collaborating with another EPSRC Early Career Fellowship holder, Dr. Cornelia Rodenburg (EP/N008065/1), hyperspectral secondary electron imaging was used to visualise and map silk protein structure formation as a result of flow in the spun fibre, which allows us to validate and reverse engineer the natural spinning process (Wan et al, Advanced Materials 2017). Translating the practical expertise developed surrounding silk protein materials, a collaboration with T. Knowles in Cambridge led to the invention of a novel route to microfluidically process silk proteins into protective capsules for protein delivery (Shimanovich et al. Nature Communications and WO2016034730).

 

Recent research highlights are the development of a fundamental set of silk mechanical properties in part to be used in simulation (Laity, 2016), which was used to show that silk is spun via pultrusion not extrusion (Sparkes and Holland, 2017, Nature Communications) and in current modelling efforts (collaboration with Prof. McLeish as part of his Advanced Fellowship EP/N031431/2, Schaefer et al, Macromolecules 2020). Collaborating with another EPSRC Early Career Fellowship holder, Dr. Cornelia Rodenburg (EP/N008065/1), hyperspectral secondary electron imaging was used to visualise and map silk protein structure formation as a result of flow in the spun fibre, which allows us to validate and reverse engineer the natural spinning process (Wan et al, Advanced Materials 2017).