Engineering materials from an understanding of nature - Ingenta Connect
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Impact Objectives
• Investigate the material properties and behaviours of
various biological and engineering materials in different
environments at multiscales
• Investigate how nature designs materials with atomic
precision using computational modelling
• Apply learnings to develop innovative materials with
advanced functions
Engineering materials from
an understanding of nature
Assistant Professor Chia-Ching Chou is using computational modelling to extend understanding of the
origin of the material properties and benefit the design of nature-inspired materials
Can you explain My research focuses on computational the change of materials’ composition or
how you are using investigations of the mechanics of biological structure at the microscale can be linked
computational and engineering materials. We investigate to the change of the materials’ behaviour
modelling to the material properties and behaviours of at the macroscale. From our recent
uncover knowledge various biological and engineering materials study into the effect of mutation in the
about the way in different environments at multiscales. epithelial protein, our simulation shows
nature designs Through a series of simulations and that the local mutations in sequence don’t
materials? numerical analysis, my research will provide necessarily alter the secondary structure
fundamental explanations of the origins formations, but the interaction of amino
Nature uses surprisingly simple building of mutability of materials and enable the acids might affect the higher order assembly
blocks to design and make materials with design of novel materials for biomedical and of intermediate filament and lead to the
intriguing properties, such as light weight, engineering applications. The outcome of change of material’s properties. The results
high strength and remarkable toughness. the studies will extend our understanding could be correlated with diseases associated
Of the basic chemical elements, there are of the origin of the materials’ properties with genetic mutations and other structural
only 20 different amino acids in proteins and benefit the current studies on nature- defects in epithelial keratin to understand
which is fascinating to me. I am working inspired materials to improve their design. the effect of each mutation and develop
on understanding the design of natural possible treatments.
materials and how this relates to a given Can you share a little about what you
material’s composition and properties. Now, have discovered so far from your studies? Are there any findings from these studies
with new electronics devices development, In particular, about local mutations and that you are particularly pleased with?
affordable computational resources, and the structural formations?
breakthrough of computational algorithms, We are very happy to see the approach
the field of computational modelling provides I have studied keratin proteins since I was we developed can successfully construct
great opportunities to investigate how nature a PhD student at Massachusetts Institute a proper atomistic structure as an initial
designs materials and apply those learnings of Technology (MIT). My PhD supervisor, model for the study. In addition, from the
to the development of innovative materials Markus Buehler, first introduced me to simulation of the epithelial protein, we can
with advanced functions. this material and I continued the study at reveal the molecular detail of the effect of
National Taiwan University. We developed local mutations on the protein structure and
You are based at the Institute of Applied a multiscale approach to exploit the higher order assembly.
Mechanics, National Taiwan University. What mechanism of materials’ composition,
type of research are you involved in at the structure, behaviour and mechanics at
Institute? different scales. We have learned that
www.impact.pub 27
Uncovering the properties
of hair and skin keratin
A team based within the Institute of Applied Mechanics at National Taiwan University is investigating
the molecular mechanisms and mechanical properties of different types of keratin. The findings will help
to decipher how the structures of particular materials relate to their distinct functions and help integrate
nanoscale approaches to engineering problems
Recent developments in electronics, One of the team’s investigations involves want to provide details that explain how
computers and computational modelling looking at the molecular mechanisms and the molecular composition affects the
are enabling researchers to analyse mechanical properties of epithelial keratin mechanical properties from a fundamental
the properties of materials that could and trichocyte keratin using multiscale point of view, as well as discussing the
dramatically improve engineering processes modelling. ‘Keratin is a type of intermediate mechanism in different hierarchies of
and even the ways we treat certain diseases. filament protein and can be found in our keratin.
Assistant Professor Chia-Ching Chou leads a hair and skin. For the hair keratin (trichocyte
team that is taking inspiration from nature. keratin), it is very tough (which is why the COMPUTATIONAL MODELLING
prince can use it to climb up the tower in To aid their research, the team is using
EPITHELIAL KERATIN Tangled!), but has low extensibility,’ explains atomistic and multiscale computational
AND TRICHOCYTE KERATIN Chou. ‘From an engineering perspective, modelling. ‘My team focuses on developing
Based within the Institute of Applied hair keratin is an extremely durable material a bottom-up approach to investigate the
Mechanics at National Taiwan University in that has been widely used in commercial relationships of structure, behaviours and
Taiwan, Chou forms part of a project funded products for over 2,000 years, such as wool properties of the biological materials in
by the Ministry of Science and Technology in the textile industry.’ different environments at multiscales,’
in Taiwan that is working to understand the highlights Chou. ‘Molecular dynamics
molecular mechanisms and mechanical The other type of keratin the team is simulation is a powerful tool for us to
properties of materials. studying is skin keratin (epithelial keratin) investigate the composition, structure and
which cannot sustain the same load as behaviour of materials at the molecular level
The hope is that by uncovering the precise hair keratin, but has larger extensibility. and it can be further applied to predict the
structures and mechanisms - and how they Interestingly, while both hair and skin properties of materials if a proper model is
affect the properties of a given material - keratin share a high order of similarity, used.’
the team can apply those findings to the in terms of their molecular structure
development of new materials that will help and hierarchical assembly, the molecular The team starts from the study of
solve a number of problems. structure of hair keratin has stronger microscale models of materials using
interactions, which enables it to better molecular dynamics simulation (MD) and
resist external influence. The team therefore extracts the information from MD to build
28 www.impact.pub
a larger model to investigate the behaviour There are other challenges too. ‘It is understanding how mutations in chemical
at the macroscale. ‘By studying hair and not easy to find keratin mesoscopic compositions can affect the structure and
skin keratin, we want to provide an answer experimental data for us to compare mechanical properties of a material. The
regarding how sequence and chemical the established meso-scale biomaterial protocols they use could one day be applied
By studying hair and skin keratin, we want to provide an answer regarding how sequence
and chemical bonding affect the microscopic, mesoscopic and macroscopic level properties
of materials and contribute to the materials’ distinct properties
bonding affect the microscopic, mesoscopic model, so the experimental data of similar to the study of other fibre-like materials and
and macroscopic level properties of materials, vimentin intermediate filament, their mechanism, which could potentially
materials and contribute to the materials’ was compared first,’ says Chou. ‘When be exploited in the design of bio-inspired
distinct properties,’ confirms Chou. Through we use conventional MD simulations, we polymers, fibre materials, novel composites
the use of MD, they will provide insights sometimes face time scale and chemical and targeted drug delivery systems. l
into the mechanisms of chemical bonds in reaction limitations and may not be able to
materials and illustrate the importance of solve representative molecular structures.’
the environment which the material finds To overcome the challenge, they have
itself within. chosen to use advanced MD simulations,
such as Replica exchange molecular
Project Insights
Importantly, by elucidating the link between dynamics. This has helped the team to break FUNDING
the chemical composition, protein structure through the time scale limitations and solve Ministry of Science and Technology
and properties of different keratins, the representative molecular structures. (Taiwan): Grant number
team will be able to build knowledge of 1082218E002072MY2
other fibre-like materials. ‘In addition, we FUTURE PROGRESS
TEAM MEMBERS
hope to learn how mutations in chemical Chou is now developing their model to
Chien-Yu Pan, Chen-Yu Yang, Tsung-Wan
composition affect the structure and study the properties of keratin fibrils at a Hsiao, Yu-Chang Lai, Tzu-Lun Huang
properties of keratins, and apply those larger scale. ‘Recent studies have shown
results to diseases that are caused by that the keratin intermediate filament CONTACT
mutations,’ Chou outlines. network plays an important role in a cell’s Assistant Professor Chia-Ching Chou
response to tensile and shear stresses,’
clarifies Chou. ‘From the larger model, T: +886 2 33665639
CHALLENGES WITH COMPLEXITY
E: ccchou@iam.ntu.edu.tw
Understandably, given the complexity of we can further study the mechanisms of
W: https://sites.google.com/g.ntu.edu.tw/
the project, the team has faced a number the keratin network in a cell’s response to ccchou
of challenges which they have worked hard tensile and shear stresses and the effects
to overcome. ‘For certain keratin protein of various single-point mutations, which BIO
molecules whose molecular structure would help us understand the effect of each Dr Chia-Ching Chou received her PhD
has not been solved by experiments or mutation and develop treatments.’ They degree from MIT. She is an Assistant
are also planning to apply this approach to Professor in the Institute of Applied
simulation, the team uses homology
Mechanics, National Taiwan University.
modelling methods or previous in-house build other keratin proteins and investigate
Her research interests are associated
approaches developed by the group to build how the environmental influence affects the with the employment of atomistic and
an initial model,’ points out Chou. However, structure and mechanical property using full multiscale computational modelling
there are limitations to the crystal protein atomistic models. to understand the mechanics of
structure they use as a template, so they materials, including biomaterials and
combine the results to build a full-length Ultimately, Chou and the team are filling synthetic materials at the nanoscale and
in knowledge gaps that are vital to our microscale, with an aim to integrate
model.
nanoscale approaches to engineering
problems.
Atomistic model of keratin k5/k14-2B heterodimer
www.impact.pub 29You can also read
