Freeze-drying microscopy is a technique used to identify vital formulation parameters for products undergoing lyophilisation. Linkam have created compact freeze drying solutions ideal for both research and industry. Read more about freeze drying microscopy and the Linkam freeze drying stages here.
A huge congratulation to Brian and Jackie Golder who recently celebrated their 20th anniversary as part of the production team at Linkam. We celebrated their hard work and dedication by throwing a small party, where the whole team got together to tell old stories and enjoy delicious finger foods and desserts.
Brian and Jackie were awarded a Linkam trophy in honour of their hard work, as well as £1000 toward a holiday destination of their choice.
From everyone here at Linkam, thank you both for your hard-work and commitment, we hope you have the holiday of a lifetime. You deserve it!
We're excited to get going with this year's projects and have plenty of new products that we will be launching throughout 2017. For regular updates keep an eye on the website, Twitter and LinkedIn pages.
We'll also be exhibiting our products at several trade events across the globe. You can find details of the shows Linkam, and our distributors, will be attending in 2017 on our Events page.
We’re continually aiming to improve our stages and customer satisfaction, that’s why we’ve launched the brand new THMS-CKE600.
Building on the success of the original THMS600, this variant scraps the metal interior for a soft spongey one. The Linkam engineers also removed the heating block and piping for some much tastier jam and cream.
After some steady rolling and layering, the base of the stage body was complete.
Although the THMS-CKE600 can not do the classic heating and cooling, it tastes pretty nice.
Unfortunately this is just a prototype!
2016 has been an amazing year here at Linkam. With the continuing success of the company, Linkam is forever growing and we’ve had the pleasure of adding five new additions to the team this year.
We’ve also had the opportunity to attend many different shows all over the world, giving us the chance to showcase our stages, talk to customers and learn more about how our stages are being used in real-world applications.
This year has also seen several new stages and system launches, which have all proved highly popular in a variety of different fields. The Linkam team are always working on new developments. You can keep up to date with all our new releases on our website, as well as on Twitter and LinkedIn.
Let’s end 2016 with a throwback to a Linkam Christmas favourite:
We wish you all a Merry Christmas and happy new year!
The Linkam team recently enjoyed a great afternoon of family fun on Epsom Downs, home of the famous Derby Stakes horse race.
We were joined by our partners and families for our trip to the Downs where we enjoyed a wide array of finger foods, beverages and desserts.
While some enjoyed a relaxing afternoon on the grass, others took part in some high intensity sports and kite flying. We were also lucky to have some talented artists in the midst who did some great face painting for the kids.
All in all it was an enjoyable afternoon for the entire family. A big thank you to Jim Hayward, one of our great production engineers, for organising a lovely day out. We’re looking forward to the next one!
By Tabassum Mujtaba
From the mating dance of the peacock spider to brood parasitism in the common cuckoo, behavioural ecology is a fascinating and complex science. It is defined as the study of the evolutionary behaviour of animals due to ecological selection pressures, and even the smallest of organisms such as bacteria can effectively emulate eukaryotic social behaviours.
Streptomycetes are one such genus which can form multi-cellular colonies with distinct multi-nucleated hyphae structures. These hyphae have distinct compartments separated through infrequent cross-walls. The group is also significant due to their medicinal purpose; they produce over half of the world’s antibacterial and antiparasitic drugs and are commonly known for their forest like smell caused by the organic compound Geosmin.
The group harbour perplexing traits and behaviours. When mechanically macerated, the hyphae surprisingly do not ‘bleed’ to death suggesting the end is plugged and compartmentalised. Furthermore, growing hyphal tips can form up to 100 septa and in such multi-nucleated species, which lack DNA damage control proteins, we are left wondering how DNA can be protected from intense intra-cellular movement.
Imaging cells is a great way of gaining insight into the complex intracellular machinery and dynamic processes. Cryo electron microscopy is a popular method, however the process is sensitive and labour intensive. Fluorescence microscopy although sensitive to biological processes, lacks imaging of the cell morphology and resolution.
Cryo-CLEM is a technique which combines the high resolving power of electron microscopy with the specific labelling capacities of fluorescence microscopy, creating a better picture of cellular mechanics by imaging the same sample location and superimposing the complementing information.
For such a technique Linkam, alongside Professor Bram Koster and his laboratory at Leiden University Medical Centre, created the cryo-stage CMS196M. Fluorescently labelled samples are embedded in vitrified “glass like” ice and under cryo-conditions the fluorescence signal and the structural details are preserved.
September’s Paper of the Month is a collaboration between the laboratory of Professor Gilles Van Wezel and the Koster laboratory and their work using the CMS196M to answer the questions surrounding the complex behaviour of Streptomyces albus.
They conducted fluorescent light microscopy which highlighted gatherings of lipid blebs within hyphae structures. Through the use of cryo-CLEM they were able to directly label these molecules and visualise them in frozen samples allowing the study of fine cellular details in 3D.
These assemblies were termed cross-membranes and were found to span across various hyphal regions between cell wall and cell membrane.
Visualisation studies and permeability assays determined a number of these cross-membranes are impermeable, thus explaining how the bacteria may survive physical maceration. Furthermore comparative visualisation with chromosomes showed the cross-membranes create nuceloid free zones, thus explaining how the bacteria undergo severe compartmentalisation without suffering from DNA damage.
When discussing the motivations of their work, Dr Roman Koning said: “The motivation of our correlative cryo light and electron microscopy research was twofold, having both a technical and biological goal.
In terms of the biology, we found occasional intricate lipid structures in Streptomyces bacteria. Streptomyces are long bacteria that grow in soil and waters, do not divide by fission and have a branched mycelium. We wanted to be able to image specific lipid structures in Streptomyces in order to find out what their structure and function could be.
Since these structures were sparse they were difficult to find by cryo-EM and therefore we tried to locate these lipids by chemically tagging them and localizing them using fluorescence microscopy, after which we imaged the same positions using cryo electron tomography in order to get to know more of what they look like. Additionally many additional (light microscopy) experiments were performed to determine and prove what their function is.
It appeared that the lipid structures are formed by lipid tubes between the cytoplasmic membrane and the cell wall that can constrict the cell cytoplasm and thereby completely divide it, forming different cellular compartments without fission”.
Through the power of cryo-CLEM the group were able to uncover many of the perplexing mysteries surrounding the unique behaviour of Streptomyces albus. It is exciting to consider the future use of the cryo-CLEM technique and the scientific unknowns we have yet to uncover.
By Tabassum Mujtaba
Celler, K. et al. Cross-membranes orchestrate compartmentalization and morphogenesis in Streptomyces. Nat. Commun. 7:11836 doi: 10.1038/ncomms11836 (2016).
When you next take a train from St Pancras have a think about what might be going on beneath your feet.
Just across the road from the station, and 28 metres below the pavement, world leaders in their field are working with some of the highest resolution microscopes on the market to investigate the causes of cancer and other diseases.
The recently opened Frances Crick Institute brings together scientists from all over the world under one roof and is a partnership between Cancer Research UK, Imperial College, King's College, the Medical Research Council, University College London and the Wellcome Trust.
I was privileged to be invited to visit recently and I would like to thank the Head of Electron Microscopy, Lucy Collinson, and her colleague, Marie Charlotte, for an extremely interesting tour of the labs. Lucy and her team only moved in a few weeks ago, but already had systems up and running and collecting data - even though they were still surrounded by packing cases.
It was great to see the Linkam CMS196 Cryo Correlative stage was already unpacked and ready to start work.
Siting some of the most sensitive scientific instruments in the world so close to one of the busiest train stations in the country was always going to be a challenge. Ensuring that the vibrations from the London Underground and Eurostar do not affect their research has led to some novel civil engineering solutions providing vibration isolation flooring.
Everyone had big smiles on their faces, and no wonder. The bright and roomy new labs and microscopy rooms, the meeting spaces and offices all make for a great working environment, and it’s a far cry from their previous location. It all feels very conducive to continuing and advancing the great work being done.
The Crick is clearly going to be one of the foremost international life science research facilities and great advancements in our understanding of life will be made there.
By Duncan Stacey
Is it a fungus? Is it an alga? No it’s Staphylococcus aureus.
The last 400 years has seen rapid advancements in the technical capabilities of microscopes, allowing scientists to answer such questions by exploring a world not visible to the naked eye.
Providing a realistic sample environment is also integral to understanding science in the real world. This is where Linkam comes in by creating sample characterisation chambers which work in conjunction with microscopes and spectrometers and allow control of physical parameters around samples.
As one of the leading international companies in this field it was vital that we attended the 16th edition of the European Microscopy Congress (EMC) which only happens every four years and was held this year at the Lyon Convention Centre from 28th August to 2nd September.
EMC gathered over 2500 visitors and proved to be an excellent event to showcase our stages which included the DCS600, the RH95 system, the TST350 tensile stage, WS37 warm stage, the LTS420E and the CMS196M Cryo-CLEM stage.
Each morning featured a cutting edge plenary lecture delivered by some of the world’s leading scientists. One of our favourites was that delivered by Professor Bram Koster, head of the Electron Microscopy in the department of Molecular Cell Biology at Leiden University Medical Centre. His talk centred on electron microscopy techniques and applications and featured our very own cryo-CLEM stage – the CMS196M.
Cryo-CLEM is a new and emerging technique to combine the individual advantages from both Fluorescence and EM by imaging the same sample location with both techniques and superimposing the complementing information. The CMS196M provides a perfect solution for the correlation of high resolution structural information with biochemical processes within cells and as such proved a very popular product during the show.
The convention centre was situated in the beautiful city of Lyon and we were lucky enough to be sandwiched between the Parc de la Tête d'Or and the River Rhone. We enjoyed warm summer evening walks along the river and dined on exquisite French cuisine.
We would like to say thank you to those we spoke to during the conference and we look forward to seeing you all for the next EMC - Copenhagen 2020.
By Tabassum Mujtaba
Thermophotovoltaics (TPV) is the conversion of thermal radiation released by a thermal emitter into electricity by means of a photovoltaic cell.
Power generation with a TPV system can be envisaged for almost any process and an absence of moving parts has the advantage of low maintenance costs. Thermal emission scales with temperature to a power of 4, meaning temperature above 1000 °C is required to generate significant power in such systems.
However, the wide spectral width of thermal radiation limits the efficiency of TPV conversion as only part of the spectrum is accepted by the photovoltaic cell. A tight control over the thermal radiation spectrum is required to prevent energy dissipating into the environment. The emitter is structured in such a way as to emit thermal radiation outside the required spectral range.
Current methods use structural resonances to control thermal emission. These require complex lithography and possess intrinsic angle dependent spectral variations.
August’s Paper of the Month by Dyachenko et al., attempts to solve the TPV efficiency problem by designing and using a unique refractory metamaterial as an emitter instead of the traditional structural resonances. This metamaterial is engineered to prevent emission of long wavelength photons through a specifically engineered transition from dielectric to metallic response.
Metamaterials are traditionally made of layers of repeating composite material, designed to have a particular property which is not found naturally. The group designed a new metamaterial made of layers of tungsten and a dielectric material to create a refractory material with unique high temperature stability and selective thermal emission.
Dyachenko et al., conducted several verification experiments to test whether their unique metamaterial matched up to the theoretical expectations. Results indicated a strong absorptivity at short wavelengths and suppression of absorptivity at longer wavelengths, an important parameter for emitters in TPV systems. As the thermal emissivity and absorptivity are equal in reciprocal systems, then the same selective properties are expected for thermal emission. It was also shown that the obtained properties are almost angle independent.
By placing the metamaterial under cycles of extreme thermal stress, they were able to test the thermal stability of the material. The metamaterial was subjected to high temperature annealing experiments in the Linkam TS1500V stage. They chose to use the TS1500 as it allowed measurement of in-situ reflection and emission spectra of the samples using an FTIR spectrometer with a microscope at extreme temperatures up to 1500°C and under vacuum conditions.
The results were encouraging with optical characteristics being stable up to 1000°C supporting its thermal stability for TPV systems.
The refractory metamaterial does not need lithography and can be deposited by alternating magnetron sputtering. The highlight of the work is the support for the thermal stability and spectral properties of the unique metamaterial for TPV systems.
The last century has seen remarkable advancement in theoretical and practical therapeutics. One such development is cell cryo-preservation: the process of freezing cells and preserving them for future transfusions. Current methods involve the introduction of cryo-protectants, such as DMSO and glycerol, and freezing to levels below which biochemical reactions cannot occur.
Cryo-preserved cells are vulnerable to Ice Recrystallisation (IR). This is the formation of large ice crystals at the expense of smaller crystals and occurs during repeated freezing and thawing events. These crystals can rupture cell membranes and thus post-thaw cell numbers are often much lower than the number frozen. IR is a major factor in causing primary graft failure in transplantation patients.
Red blood cell transfusions are life changing procedures to those who have suffered from significant blood loss or for those suffering from illnesses such as leukaemia. In order to freeze samples of red blood cells (RBCs), the cells undergo an extensive glycerisation process – 40% V/V. However prior to transfusion, glycerol must be removed to less than 1% v/v to prevent haemolysis, but de-glycerisation is a lengthy process which prevents this method of being used in emergency situations.
Current cryo-protectants do not control or inhibit IR, thus it is necessary to find new cryo-protectants that can control IR to improve the success of the cryo-preservation process.
July’s Paper of the Month by Briard et al., discovered a novel class of carbohydrate derivatives with ice recrystallisation inhibiting properties that retain potency at lower glycerol percentages. The new ice recrystallisation inhibitors (IRIs) are of low molecular weight making them ideal additives to cellular systems. Briard et al., tested the ability of these molecules to reduce ice recrystallisation and ultimately improve the survival rate of cryo-preserved cells.
The group used human red blood cells (RBCs) to test the properties of the IRIs as experimental assay procedures have long since been established for RBCs. One aspect of the experiments treated the RBCs to 15% glycerol, compared to the 40% clinical standard, in an attempt to reduce the post thaw processing time.
They recreated typical cryo-cell conditions to get a real estimate of the effect of IR inhibitors on frozen cell samples. They used the Linkam FDCS196 to freeze the RBC samples and image the effect of the IRIs on ice crystal sizes. The inhibitor’s presence was found to reduce mean ice crystal size, resulting in a higher rate of cell integrity.
The transportation of cells between storage and medical facilities results in frozen samples being exposed to ambient temperatures repeatedly. Such phenomena are known as transient warming events (TWEs) and are understood to debilitate cell viability. The cyclic exposure to ambient temperatures followed by freezing temperatures can increase the size of ice crystals explaining the damage to the cells.
The group tested the effect of IRIs on crystal size during TWEs. In the presence of the inhibitors, mean ice crystal size was not found to increase during TWEs, however in the absence of the IRIs the crystal size increased. The increasing size of ice crystals play a major role in the reduction of post thaw viability.
Professor Ben, of the research group, discusses the motivation behind his work and the role of the FDCS196:
“The Linkam cryostage is an essential piece of equipment to perform the studies we described. Our motivation to design these compounds is twofold. Firstly we have always been interested in understanding the nature of the cryo-injury that cells/tissues sustain upon freezing and secondly we use this information to design new and greatly improved cryo-protectants that will enable the many novel cellular and regenerative therapies that are currently being developed. The current problem is that there is no shelf life to these cellular products as they cannot be cryo-preserved efficiently.”
These studies found aryl-glycosides to be the most potent of their IRIs. Their experiments confirmed the introduction of IRIs to the 15% glycerol samples significantly increased post-thaw viability to approximately 90% for aryl-glycosides. Cryo-microscopy confirmed the ability of the inhibitors to reduce mean ice crystal size and IR during TWEs, which in turn increased post thaw viability. Their work provides promising results by addressing issues with current cryo-protectants and with further study, may pave a way for improved cellular cryo-preservation in the future.
By Tabassum Mujtaba
Briard, J. G. et al. (2016). Small molecule ice recrystallization inhibitors mitigate red blood cell lysis during freezing, transient warming and thawing. Sci. Rep. 6, 23619
The Linkam team are always looking for engaging and dynamic shows to showcase our wide range of stages. Last month we visited the Diamond Light UK Bio-XFEL Single Particle Imaging Workshop in Didcot, the home of the UK’s largest synchrotron.
X-ray Free Electron Lasers are electrons which have been accelerated close to the speed of light. The frequency of these waves lies within the range of x-rays, 3×10 16 Hz to 3×10 19 Hz. This beam of tiny particles releases packets of energy, and this radiation has many different practical applications.
The energy released by these waves is powerful enough to image bio-molecules, this in turn eliminates the need of crystallisation methods to determine 3D macromolecular structures.
Speakers from all over the globe came to deliver cutting-edge talks in biological imaging. An interesting range of talks were delivered, such as Changyong Song’s “XFEL single-shot imaging of specimens on fixed targets” and Helen Saibil’s “Single particle cryo-EM of macromolecular machines”.
We would like to thank the organisers for holding such an insightful show and we look forward to seeing you all soon at the next Bio-imaging event.
What gives chocolate its rich creamy texture? How can we keep the creaminess while reducing the fat content? For almost a century Leatherhead Food Research (LFR, www.leatherheadfood.com) has been analysing and answering such questions by looking at the intricate microstructures of food. By doing so, Leatherhead has supported and contributed hugely to the progression of the food and beverage industry.
We recently paid a visit to their facility in Leatherhead, Surrey. Kathy Groves, Head of Science & Microscopy, has been using the Linkam Optical Shearing System – CSS450 – to analyse the microstructures of various foods.
One of the more important sectors they focus on is research into helping the food and beverage industry develop healthier products. With a quarter of people in England classified as obese, there is a clear need to replace high calorie foods with lower calorie versions. But finding healthy replacements for flavoursome salt, fats and sugars is a challenge. For the public to embrace these changes, the products must have similar taste, texture and physical properties as their less healthy predecessors.
With its shearing function and temperature control, the CSS450 provides the perfect sample characterisation chamber to analyse the microstructure of new formulations. The imaging option of the system allows changes in sample structure to be visualised and comparative differences to be analysed. This gives key information on how food and drink behave when sheared, such as happens in the mouth.
Linkam products have great potential for use in food research. We demonstrated some of our other stages to Leatherhead, including the humidity system – the RH95, which can alter the relative humidity and temperature around samples, making it a great system for shelf life testing. The stages created much interest, which reinforced our belief in the need for our products within this market.
We would like to thank Kathy Groves and Leatherhead Food Research for inviting us to their laboratory and providing us with essential insight into the food research market.
By Tabassum Mujtaba
Just like the human body, cells require a skeleton to guide growth, support and movement. This essential ‘cytoskeleton’ is comprised of a particular set of proteins present in all cellular organisms: humans, plants, animals and even bacteria.
June’s Paper of the Month by Elie et al. focused on the role of a neuronal protein, Tau, and its link to two major cytoskeletal proteins: actin and microtubules.
These cytoskeletal filaments have a well-established dynamic and synergistic relationship in terms of cellular growth, division and movement. However the molecular basis governing this synergy remains poorly understood, although several proteins have been identified as potential ‘linkers’ between actin and microtubules. As they play a crucial role in cellular function, determining the mechanics of their relationship is fundamental in understanding cellular irregularities and pathologies.
Tau is a neuronal protein known to promote the polymerisation of microtubules along the body of nerve cells and regulate the actin cytoskeleton. As such, it becomes an excellent candidate for further experimentation as a co-organisational protein of actin and microtubules. Elie et al. investigated Tau’s ability to simultaneously organise both proteins.
Through live Total Internal Reflection Fluorescence (TIRF) microscopy, they found tau induced a bundling effect on actin. Co-sedimentation assays of tau with both cytoskeletal proteins, illustrated tau as a cross-linker between actin and microtubules. Through these cross-links, macro-molecular structures were able to form.
Microtubule and actin polymerisation is temperature-dependent thus these parameters were strictly controlled. They used the Linkam MC60 warm stage controller to control the temperature parameters for their live TIRF microscopy experiment.
Fluorescently labelling proteins is a popular way of visualising protein localisation and interactions. Co-ordination experiments were conducted by fluorescently labelling actin and microtubules. They visualised their concomitant polymerisation and organisation in the presence of fascin – an actin bundling protein – and tau. In presence of fascin they found only actin bundled together with no effect on microtubules or microtubule-actin co-ordination. However in the presence of tau, growing microtubules and actin filaments were found to co-align with each other, confirming tau as a cross-linking protein of these two major cytoskeletal elements.
Recent studies have highlighted tau protein presence in junctions between neurons. Elie et al., propose that tau may participate in the microtubule/actin coordination that controls synapse formation and function. Uncovering some of the mystery around cytoskeletal organisation will have important medical repercussions. Abnormal tau protein is linked with Alzheimer’s, a neurodegenerative disease. Advancements in understanding such intricate protein relationships may aid in further unearthing the pathways which lead to cytoskeletal pathologies.
By Tabassum Mujtaba
At Linkam each of our stages are designed and built in-house by our experienced engineers. Machining is a lengthy process and production time is limited by the capabilities of the equipment. Investing in new machinery is just one way in which Linkam endeavours to improve business practice and overall customer satisfaction.
Our newest gadget is the HAAS Automation VF-4SS which will be used right in the heart of production. The ingeniously designed side-mount tool changer holds 40 different tools, providing an “all-in-one” feature for stage production. The internal capacity of the machine now allows some of our bigger stages to be made in one production cycle, without the need for other machinery.
Dan Kirk, our production manager, reports on the new tool: “With the new VF-4SS, we’re expecting significantly reduced production times. It can hold more tools, house bigger stages and it incorporates the programmes we used previously. We’re looking forward to much more efficient and faster production runs.”
By Tabassum Mujtaba
Linkam high temperature stages are used in a wide variety of applications including geology, metallurgy, ceramics and high temperature polymers. When some samples are heated to high temperatures, they can release volatile components which condense on the window, obscuring the optical path. To overcome this, Linkam engineers have developed a simple but extremely effective solution. The new HS1500 stage incorporates a large window that can be rotated to move a clear area into the optical path.
Operating up to 1500 °C, the unit features a 55 mm rotatable quartz window which allows the user to turn the window to a new, clear, area during the experiment if they observe volatile emissions settling onto the viewing window. This new functionality is especially useful in observing how materials such as ceramics, metallic alloys, polymers and many more react to ultra-high temperatures, without compromising the image quality.
The HS1500 stage features a ceramic heating cup which when used in conjunction with the ceramic cover creates a micro oven around the sample and heats at an incredible rate of up to 200 °C/min. The stage body has precision quick-release gas valves which can be used to purge the sample chamber with an inert gas to reduce any oxidation effects on the sample itself.
Sales and Marketing Manager, Dr Duncan Stacey, says of this launch: “At Linkam, we are continually talking to our customers, listening to their ideas and suggestions. The HS1500 is a great example of how we listened to an issue affecting some of our customers and developed a simple but effective solution.”
To learn more about Linkam and our approach to the development of temperature stages to address multiple applications challenges, please visit our website.
Andrology is a profoundly important and sensitive area of health research. Many different factors can lead to a decrease in male fertility, for example, cancer treatments, illnesses, and age, so studying and storing healthy sperm samples from such males becomes an important measure in ensuring their potential to father children in the future.
The Association of Biomedical Andrologists (ABA) is a group dedicated to aiding andrologists in male health research. We recently attended the 11th ABA annual general meeting in Cardiff from the 18th to 19th May, where many topics such as semen analysis and preservation were explored.
The event was held in The Angel Hotel, which is a stone’s throw away from Cardiff Castle. The castle is one of the biggest heritage attractions in Wales and boasts a rich history dating back almost 2000 years, featuring Romans, Normans and Victorians. Beautifully sculpted stone animals designed by William Burges line the outside walls of the castle. It is a stunning site with the ancient architecture still withstanding the forces of time.
We showcased our upright and inverted WS37 warm stage systems, both designed with andrology in mind. The systems proved very popular among the attendees, many of whom commented on the practicality of the features. The extremely accurate temperature control, data logging and the liquid crystal validation slide make the WS37 warm stages the ideal solution to provide repeatable conditions for Sperm analysis – a necessary feature for the andrology community.
In the evening, a lovely Welsh-themed conference dinner was held for the attendees, serving potato and leek soup, Welsh roast lamb and Barabrith honey cheesecake – which tasted surprisingly like Christmas pudding!
The final day saw some much anticipated events such as ‘Question Time’, the annual general meeting and the andrology debate: ‘Is the routine testing of antisperm antibodies clinically useful in the management of the sub-fertile male?’
It proved to be another exciting and successful trip for Linkam. We would like to thank the ABA for holding a superb event and thank you to all those who came over for a chat. We hope to see you all again next year.
By Tabassum Mujtaba
May’s ‘Paper of the Month’ is a collaboration between a number of different laboratories and Institutes: the Max Planck Institute of Colloids and Interfaces, Nanyang Technological University, Massachusetts Institute of Technology and the Wyss Institute for Biologically Inspired Engineering.
Their paper ‘Multi-scale thermal stability of a hard thermoplastic protein-based material’ determined the thermal properties of a potentially novel and sustainable biopolymer to replace the unsustainable petrochemical polymers we rely so heavily on today.
Since the industrial revolution, petrochemicals have been used extensively: in aromatics, plastic production, and fuel. Not only are they environmentally damaging but reserves of petrochemicals are running out. They take millions of years to form, and substantial use of them over the last two centuries means future generations will have to go without.
Yet their chemistry and structure are excellent for creating thermoplastics. When heated, weak forces of attraction between polymer chains – intermolecular forces – break, allowing the chains to move past each other and the plastic to be reshaped. When the plastic cools, these bonds reform and the new shape is held.
In contrast, thermosetting plastics have a strong cross linked network of bonds, which allows them to retain their shape when heat is applied, although extreme temperatures will cause both thermoplastic and thermosetting plastics to permanently decompose. Thermosetting plastics have many useful applications but thermoplastics’ wide commercial use comes from their ability to be reheated and reshaped a number of times.
The search is on to find alternatives to petrochemical based polymers, but it is challenging because not many biopolymers have the chemical properties required to replace thermoplastics. Even when such properties are induced through chemical processing, the biopolymers often lose the integrity of their physical nature. However, one exception may be Sucker Ring Teeth (SRT), made of a protein called Suckerin, which is found in the tentacles of squid and cuttlefish.
The research group first molecularly characterised the macromolecule to find it displayed many of the chemical properties true to thermoplastics. Hydrogen bonds – a type of intermolecular force – are found between SRT’s β-sheets and, just like thermoplastics, when heated these bonds break and SRT can be reshaped.
Using X-ray scattering, spectroscopy and nano-mechanical techniques, the group determined its molecular mechanical and thermal properties. Using the Linkam THMS600 stage, which can control the temperature of the sample from -196°C to 600°C with an accuracy of 0.01°C, they precisely varied the temperature to test the thermal properties of SRT.
Thermal extrusion experiments were conducted to test the thermoplastic nature of the polymers. With the addition of water and the plasticiser glycerol, it could be heated and cooled into various stable forms, reprocessed a number of times and proved successful in additive manufacturing. They determined SRT to be crystalline polymers of β-sheets with amorphous regions, which is structurally stable until 220°C. The properties of the treated SRT polymer are highly promising for synthetic commercial production.
By determining the thermal and molecular properties of this biopolymer, the group has established a potential sustainable alternative to thermoplastics. With the results showing potential, the future range of applications for SRT may extend to 3D printing, synthetics and biomedical devices.
By Tabassum Mujtaba
Latza, V., Guerette, PA., Ding, D., Amini, S., Kumar, A., Schmidt, I., Keating, S., Oxman, N., Weaver, JC., Fratzl, P., Miserez, A., Masic, A. (2015). Multi-scale thermal stability of a hard thermoplastic protein-based material. Nature Communications. 6: 8313