Robert Elkington

PRG4 or lubricin is a protein with a bottle-brush shape that can be perfectly mimicked by polymer brush grafting to biomaterial surfaces. This imparts to biomaterials’ surfaces super lubricous properties and a coefficient of friction (µ) lower than 0.01.  In addition, polymer brushes grafted to material surfaces may impart tunable hydrophilicity, self-cleaning, catalysis, controlled cell, and bacteria adhesion [1]. They can be applied for response actuation and drug delivery. Lubrication polymer brushes can be charged (positive and negative charges), amphiphilic, or act via steric hindrances[1]. The end properties can be controlled by molecular weight, grafting density, and radius of gyration.

One of the mechanisms of lubrication is brush hydration. The thick water film would prevent the probe from contacting the surface[1]. In nature, this role is played by hyaluronic acid and other sugar molecules in articular cartilage, for example. The sugar molecules are conjugated to lubricin forming a mucinous domain. The protein is anchored by a somatomedin-B (SMB) domain to hyaluronic acid from the extracellular matrix of cartilage cells (chondrocytes) [2,3]. The glycosylated domains can trap water and establish electrostatic repulsion promoting lubricity of the tissue [4,5]

Several strategies have been developed to mimic this biochemical environment. Poly(l-lysine) (PLL) brushes were grafted onto poly(ethylene glycol) (PEG) surfaces to obtain good lubricity and biocompatibility[6]. Morgese et al. grafted to poly(glutamic acid) different polyoxazolines. These polymers are known for passivating surfaces and promoting now-fouling without eliciting immune responses. In samples with hydroxybutyrate (HBA), she obtained a biomimetic material that could bind to degraded cartilage and regenerate tissue[7]. This implies interesting solutions for people with early-onset arthritis.

To conclude, bottle-brush materials might be the future of cartilage tissue engineering, but more studies need to be conducted to show the in vivo feasibility of the concepts. We expect these new materials to influence scaffolds/gels potentially entering the market in the next decades.

REFERENCES

[1]          S. Ma, X. Zhang, B. Yu, F. Zhou, Brushing up functional materials, NPG Asia Mater. 11 (2019) 24. https://doi.org/10.1038/s41427-019-0121-2.

[2]          Y. Lee, J. Choi, N.S. Hwang, Regulation of lubricin for functional cartilage tissue regeneration: a review, Biomater Res. 22 (2018) 9. https://doi.org/10.1186/s40824-018-0118-x.

[3]          I. Bayer, Advances in Tribology of Lubricin and Lubricin-Like Synthetic Polymer Nanostructures, Lubricants. 6 (2018) 30. https://doi.org/10.3390/lubricants6020030.

[4]          S.M.T. Chan, C.P. Neu, G. DuRaine, K. Komvopoulos, A.H. Reddi, Atomic force microscope investigation of the boundary-lubricant layer in articular cartilage, Osteoarthritis and Cartilage. 18 (2010) 956–963. https://doi.org/10.1016/j.joca.2010.03.012.

[5]          I.M. Schwarz, B.A. Hills, Surface-active phospholipid as the lubricating component of lubricin, Rheumatology. 37 (1998) 21–26. https://doi.org/10.1093/rheumatology/37.1.21.

[6]          S. Lee, M. Müller, M. Ratoi-Salagean, J. Vörös, S. Pasche, S.M. De Paul, H.A. Spikes, M. Textor, N.D. Spencer, Boundary Lubrication of Oxide Surfaces by Poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) in Aqueous Media, Tribology Letters. 15 (2003) 231–239. https://doi.org/10.1023/A:1024861119372.

[7]          G. Morgese, E. Cavalli, J.-G. Rosenboom, M. Zenobi-Wong, E.M. Benetti, Cyclic Polymer Grafts That Lubricate and Protect Damaged Cartilage, Angew. Chem. 130 (2018) 1637–1642. https://doi.org/10.1002/ange.201712534.

 

This article was written by André Plath as part of an ongoing series of scientific communications written and curated by BioTrib’s Early Stage Researchers.

André is researching Boundary Lubrication of Fibrous Scaffolds at ETH Zürich, Switzerland.

Reaching back over 2,000 years, an ancient network of trade routes called the ‘Silk Road’ connected the East and the West. Precious goods, splendid cultures and religions travelling along thousands of miles, stroke, exchanged and merged. The term ‘Silk Road’ was first used by German geographer Ferdinand von Richthofen in 1877, as silk is one of the favourite goods traded from China to Europe, also as a metaphor for the ideas travelled from different civilizations.²

Amazed by this picture (marks are the origins of all ESRs who joined BioTrib this year) and the idea of ‘BioTrib Silk Road’ presented by Prof Richard during our ESRs meeting, I started to think about the importance of international research collaboration in the modern world.

 

“Ideas transcend borders, no country controls the marketplace of ideas.”

— Alejandro Adem ³

Indeed, there isn’t a researcher who knows everything in the world, nor a university owns all of the state-of-the-art equipment and facilities. We have to collaborate, and we love to collaborate. When people from diverse backgrounds meet, idea sparks. When institutions collaborate, science thrives. While in BioTrib, deep international connections have formed between universities and industries from the UK, Sweden, Switzerland, Germany, China and Australia; researchers are not only from different academic backgrounds but also diverse cultural backgrounds. The diversity and inclusiveness are the treasures of BioTrib and I can’t wait to see our footprints of contribution to academic research on this ‘BioTrib Silk Road’.

Header Image: Marco Polo Geography and Map Division/Library of Congress, Washington, D.C. (gct00215-ca000005) ¹

 

References

(1) Marco Polo on the Silk Road https://www.britannica.com/topic/Silk-Road-trade-route

(2) The Silk Road https://www.nationalgeographic.org/encyclopedia/silk-road/

(3) The benefits and challenges of international research collaboration https://www.universityaffairs.ca/features/feature-article/the-benefits-and-challenges-of-international-research-collaboration/

 

This post was written by Esperanza Shi as part of an ongoing series of scientific communications written and curated by BioTrib’s Early Stage Researchers.

Esperanza is researching the Optimisation of Scanning Strategies for 3D Printed Artificial Joints at Imperial College London, UK.

 

The ongoing 4th Industrial Revolution has shifted the traditional paradigm of producing medical devices. Additive Manufacturing (AM), a mould-less technology commonly referred to as 3D printing, plays an essential role in the shift taking place in this field.

Because of the high degree of geometrical freedom that can be achieved, AM is being used to conceive polymeric microneedles (MNs) with tailored design. For instance, Caudill and co-workers (2021) studied the benefits of microneedle vaccination over the traditional subcutaneous one. An AM process that relies on resin photopolymerization (i.e., continuous liquid interface production) was used to fabricate the MNs in two different shapes: square pyramidal and faceted (cf. image given in this post).

Cargo loading was performed via surface coating and assessed for the different MN designs. Whilst surface area increased 21.3%, cargo loading augmented 36% from square pyramidal to faceted with horizontal grooves, which pinpoints the importance of geometry design to loading biologics on MNs. Furthermore, transdermal delivery through MN vaccination was more effective in triggering primary antigen-specific IgG as well response duration when compared to subcutaneously or intradermally delivering paths.

Caudill et al. (2021) findings represent a major step towards a simpler, effective, and pain-free vaccination process that can potentially increase global vaccination. Furthermore, this self-administered vaccination path may aid in prompt responses during epidemic and pandemic scenarios. In that sense, AM has proved to be a feasible manufacturing route for improving drug delivery systems via tailored shapes and geometries.

Read more of this fascinating paper here: Transdermal vaccination via 3D-printed microneedles induces potent humoral and cellular immunity

This post was written by Pedro Luiz Lima dos Santos as part of an ongoing series of scientific communications written and curated by BioTrib’s Early Stage Researchers.

Pedro is researching the Functional Biotribology of the Surface Engineering of 3D Printed Components at the University of Leeds, UK.

A £7 million research project has been launched to develop a new imaging and keyhole surgery approach to the treatment for secondary bone tumours of the spine. 

Known as metastatic bone disease, the tumours spread from a primary cancer located elsewhere in the body. The condition is particularly associated with breast cancer.  

The bone tumours cause vertebrae to weaken and eventually fracture, leaving people in severe pain, immobility and requiring surgery. In some cases, the fracture may damage the spinal cord and cause paralysis. For these patients, however, quality of life is a key issue and complex surgery may be inappropriate. 

A research collaboration between the University of Leeds, Imperial College London and UCL has received funding to develop an alternative approach based on developing new imaging and modelling techniques that will enable clinicians to predict which patients are at a high-risk of a vertebra fracturing.  

They would then be fitted – using minimally invasive surgery – with a tailor-made implant to strengthen the spine and prevent the fracture. 

The project – Oncological Engineering: A new concept in the treatment of bone metastases – has attracted £7 million in research funding, including £5.6 million grant from the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation, the Government-funded body set up to support research and innovation. 

According to Cancer Research UK, 150 people every day are diagnosed with breast cancer. Although more than 76% of people with the disease survive for more than ten years, some patients do develop stage 4 cancers, of which it is estimated about 50% to 60% get bone tumours.  

In stage 4 cancers, the disease has spread to other organs. 

Within five years, the research team hope to have developed new techniques and materials that will revolutionise the treatment of bone metastases.  

The approach is based on personalised medicine, assessing an individual’s risk that the spine has weakened so much that a vertebra will fracture. In those cases where surgeons intervene to strengthen the spine, the implant will be tailor-made.  

Predicting the risk of a vertebrae fracturing 

Researchers will develop news approaches to patient imaging and computer modelling, enabling them to track tumour development in the spine over time and how it might be weakening individual vertebrae. The information would be compared with the loading on the spine, enabling clinicians to predict which of the vertebrae is at risk of fracturing. 

Implant made of advanced materials 

Those vertebra at a high-risk of collapse would be supported by an implant inserted into the spine using minimally invasive techniques.  

The implant would be made from what is called a metamaterial, a material that has uncommon properties that can be fine-tuned to the needs of the patient, for example the material could harden when under stress. 

Metamaterials are currently used in the aerospace industry but with advances in 3-D computer printing, the research team believe they could be adapted to provide tailor-made structural integrity to vertebrae at high risk of fracturing. 

The advanced manufacturing group from the Dyson School of Design Engineering at Imperial College, London, will be developing a novel 3D printer capable of fabricating the intricate implant designs. Their machine will utilise smart optical systems to print photopolymers at extremely fine resolution. 

By using minimally-invasive techniques to implant the material, the recovery period for patients will be days – rather than weeks or months with the surgery that is required if one of the spinal bones fractures. 

The NHS long-term plan for cancer treatment had called on researchers to develop new interventions that would improve the quality of life of patients living with advanced cancers. 

It is hoped the new techniques will be applied to other areas of the healthcare sector.  

A year on since the start of BioTrib we have now completed recruitment of all 15 Early Stage Reseachers and achieved a milestone 500 followers on LinkedIn!

Thanks to everyone in the BioTrib community!

Additive manufacturing also known as 3D printing has rapidly evolved since the 80’s and is now a major fabrication methodology for rapid prototyping of custom-made object [1]. Its benefits are applied in many fields such as medical, academic, aerospace, robotics and industrial machinery. 3D printing encompasses different technologies like stereolithography (SLA), fused deposition modeling (FDM) or selective laser melting (SLM) using metal powder. Those printers exhibiting different workflows and using different materials allow to access wide range of possibilities for the characteristics (structural complexity, color, resolution, etc) and properties of the final constructs [2] [3].

3D printing is making great strides every year and the business market is growing with them so as to respond to customers demand and to access a wider range of applications. In order to promote these new 3D printing related innovations, Formnext is taking place every November in Frankfurt since 2015. Formnext is a global exhibition on additive manufacturing and industrial 3D printing gathering hundreds of exhibitors and thousands of visitors. This event is an opportunity for the actors of 3D printing to exchange with companies and discover novelties in terms of printers, materials, post processing solutions and software.

Formnext also represents a human experience as this convention brings together people working in a wide range of fields, from experts to beginners in 3D printing. Formnext 2021 allowed the additive manufacturing community to meet again after 2020’s edition which took place online because of COVID-19.

Now let’s see how these innovations will be put to good use!

[1] Matias, Elizabeth & Rao, Bharat. (2015). 3D printing: On its historical evolution and the implications for business. 551-558. 10.1109/PICMET.2015.7273052.
[2] Deshmukh, Kalim & Houkan, Mohammad & AlMa’adeed, Mariam & Sadasivuni, Kishor kumar. (2020). Introduction to 3D and 4D printing technology: State of the art and recent trends. 10.1016/B978-0-12-816805-9.00001-6.
[3] Wohlers Associates Inc. (2013). Wohlers report. Fort Collins, CO: Wohlers.

 

This article was written by Marie Moulin as part of an ongoing series of scientific communications written and curated by BioTrib’s Early Stage Researchers.

Marie is researching the Bioprinting of Bone and Cartilage at Uppsala University, Sweden.

Seasons greetings from BioTrib. We wish you a very pleasant winter break and a happy new year!

This concludes posting for 2021, we are looking forward to more novel and pioneering tribology and biomedical engineering research in the new year!

Should you like to make more contacts within your University? How can we maintain a social relationship during the Covid pandemic? What would happen if people from different departments and hierarchies would talk more often to each other?

These are some of the questions I asked myself before taking part in this initiative a few weeks ago. The Covid pandemic radically changed the opportunities for interaction with people. But whether a smile in passing, a quick “hello” or a lingering conversation, shared moments bring vibrancy to life. Human interaction is a necessity for everyone and the desire for connection is a core need essential to feeling satisfied with your life.

Since I started this new experience at ETH Zürich, I was eager to meet as many people as possible, from all over ETH and other institutions, to keep me socially fit and also to compare with people and deal with different perspectives and cultures and upgrade my training and skills, not only in scientific fields. So, when I saw this opportunity called ETH LunchLottery [1], which I had never heard about before, I decided immediately to sign up. Unfortunately, like me, just a few people know about this occasion to meet people and that’s why I’m interested in talking about and sharing it.

The idea here is basically to mix staff and doctoral students as much as possible, once a month, by assigning randomly every participating employee one or several lunch or coffee break partners to meet both online and in person. Then a smart matching algorithm optimizes for the perfect match. All participating employees automatically receive a customized e-mail about the upcoming LunchLottery initiative [2] and partners’ e-mail addresses. You’re ready! Employees connect with new colleagues from other departments and hierarchy levels [2]. You can decide with your lunch/coffee break partners when and where to meet them. This will help to make new connections and exchange ideas with all sorts of people. It will enrich everyday working life immensely by getting to know new people and hearing about the work they do across all units and functional levels, or just by having an exciting chat on various topics. It could also be a great idea for setting up small projects and collaborations with other departments.

And in this regard, after this experience, I asked myself: “Could we take a cue from this kind of event also to develop networks and to share our knowledge or to simply get to know better the other BioTrib’s members, also considering the different geographies and time zones? Could be an idea to get in touch and know even other ETNs’ members in the most relevant scientific fields?”. A short interruption to our daily routine could be a good idea to get to know other colleagues better and it would also help to open many doors and possibilities for all of us, as well as to gain additional knowledge and skills to help us to manage and do better our jobs. And even more, in light of the pandemic we are still immersed in, I believe it is a perfect opportunity to allow people to return to real life.

Networking and relationship building will lead to innovation!

[1] https://ethz.ch/services/en/news-and-events/events/eth-lunch-lottery.html
[2] https://lunch-lottery.com

 

This article was written by Alessio Amicone as part of an ongoing series of scientific communications written and curated by BioTrib’s Early Stage Researchers.

Alessio is investigating the Elucidation of Friction-Induced Failure Mechanisms in Fibrous Collagenous Tissues at ETH Zürich, Switzerland.