Meeting with UNICEF: What can we do to improve global arthroplasty?

BioTrib ESR, Ben Clegg had the pleasure of attending a small presentation at the UNICEF headquarters in Stockholm in December, with Ungaforskare

We had an engaging discussion on how we thought innovation could be used to improve our society. With a focused workshop on how we can service disadvantaged children in our turbulent world. What I gained from this is how we can improve and engage human connection to improve equality on all bases.

The meeting itself didn’t focus on anything specific within the medical industry, however it did stimulate a few thoughts on what we could do as early-stage researchers, something which was starkly aware of when discussing how we can aid the disadvantaged children in our previous discussions.

Within Biotrib we are all working towards an overall collective goal of improving the quality of biological implants, and I feel that we have a really great purpose as a collective. Nevertheless, it was brought to my attention that we are focusing on the cutting edge of technology which is mostly only available to those at the forefront of society.

The first things that came to my mind was the availability and access of hip replacements to those in the global south, with regards to hospitals, surgeons, equipment and money. This kind of disparity is even apparent in countries like the UK, with geographical inequality persisting in the north south divide in England [1].

So… what can we do to improve this? As early-stage researchers, I would enjoy an open discourse and increase the awareness of these issues, and maybe some of us could go on to make not just a difference in the medical field, but also aid those less fortunate than ourselves.

 

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

Ben is researching the Wear particle characterization and bio-compatibility of newly 3D printed self-lubricating polymer composites in total joint replacements at Luleå University of Technology, Sweden.

 

 

 

References

[1] Ryan-Ndegwa, S., Zamani, R. & Akrami, M. Assessing demographic access to hip replacement surgery in the United Kingdom: a systematic review

[2] Header Image:  – https://www.strategicmarketresearch.com/market-report/hip-replacement-implants-market

 

 

Recycling orthopedics, what happens after cremation?

In Sweden around 100,000 people pass away every year, and 70% of those are cremated [1]. Since 2016 it has been mandatory for the church to arrange recycling for any and all metallic components left after cremation.

Since then, 60 tons of metal has been recycled. It was calculated that a value of 250 Million dollars could be recouped per year if the Swedish numbers were extrapolated to the United states and Europe.

These metal parts are melted down back into ingots and can be repurposed into new materials. These normally cannot be re used as implant materials, due to increased chance of infection rate and if cremated have been chemically altered by the heat. But the high-grade titanium and cobalt ores can find there way into the aviation industry [2].

For future thoughts and discussion … What can we do with the implants that are not used and have been replaced the ever-advancing technologies and materials?

References

  1. Lidgren, L., Raina, D.B., Tägil, M. and Tanner, K.E., 2020. Recycling implants: a sustainable solution for musculoskeletal research. Acta Orthopaedica91(2), pp.125-125.
  2. https://www.theguardian.com/sustainable-business/2015/oct/06/metal-body-parts-hip-knee-replacements-cremation-circular-economy-recycling
  3. Header Image: https://ryortho.com/breaking/the-afterlife-of-cremated-orthopedic-implants/

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

Ben is researching the Wear particle characterization and bio-compatibility of newly 3D printed self-lubricating polymer composites in total joint replacements at Luleå University of Technology, Sweden.

The state of total Hip replacements in the developing world

Total hip arthroplasty is a fantastic operation that massively improve the patient’s quality of life. Most hospitals in the western world have access to state-of-the-art facilities which aid them with the surgery. In low-income countries, this access is limited. So how does it compare?

A study from Malawi [1] was chosen, as the first study to follow up on patients >10 years in a low-income country. The results are staggeringly positive and can even be compared to registries of high-income countries [2].

A 10-year mortality was at 20% (Malawi) vs 25% (UK) and a revision rate of 8% vs 5%. The Harris hip scores also compared rather favorably with high income countries. This is mainly attributed to the lower age of patients at an average of 52 years (Malawi) vs 68 (UK)

It should be noted that this was a relatively small study of only 70 patients, but one must bear in mind that only 3 hospitals in Malawi (a country with a population of 20 million) has the capability of performing a THA operation, and that patients live long distances from the hospital meaning they cannot afford the return journey.

Complications such as infection and dislocation are known as notable complications for this operation in low-income countries, but were not met in this study.
I think that this study reflects how well we can service people in need even in the poorest of conditions, and makes us think what good we could do by aiding countries like Malawi to improve their medical infrastructure.

 

References

[1] Graham SM, Howard N, Moffat C, Lubega N, Mkandawire N, Harrison WJ. Total Hip Arthroplasty in a Low-Income Country: Ten-Year Outcomes from the National Joint Registry of the Malawi Orthopaedic Association. JB JS Open Access. 2019
[2] National Joint Registry for England. Wales, Northern Island and Isle of Man. 14th annual report

 

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

Ben is researching the Wear particle characterization and bio-compatibility of newly 3D printed self-lubricating polymer composites in total joint replacements at Luleå University of Technology, Sweden.

Willy Wonka – an eminent biotribologist?

Researchers at the University of Leeds, Dr Siavash Soltanahmadi, Prof Michael Bryant and Prof Anwesha Sarkar based at the School of Food Science have looked into why the melt in the mouth taste of chocolate is so irresistable.

The paper Insights into the Multiscale Lubrication Mechanism of Edible Phase Change Materials investigates the lubrication behaviour of phase change materials (chocolate being one of many) from an oral tribology context.

During mastication, a phase change often occurs in a sequence of dynamic interactions between the ingested phase change materials and oral surfaces from a licking stage to a saliva-mixed stage at contact scales spanning micro- (cellular), meso- (papillae), and macroscales. Often the lubrication performance and correlations across length scales and different stages remain poorly understood due to the lack of testing setups mimicking real human tissues.

Unprecedented results from this study supported by transcending lubrication theories reveal how the tribological mechanism in licking shifted from solid fat-dominated lubrication (saliva-poor regime) to aqueous lubrication (saliva-dominant regime), the latter resulted in increasing the coefficient of friction by at least threefold. At the mesoscale, the governing mechanisms were bridging of cocoa butter in between confined cocoa particles and fat coalescence of emulsion droplets for the molten and saliva-mixed states, respectively.

Prof Anwesha Sarkar, from the School of Food Science and Nutrition at Leeds, said it is the “location of the fat in the make-up of the chocolate which matters in each stage of lubrication, and that has been rarely researched”. [BBC News]

Dr Soltanahmadi said: “Our research opens the possibility that manufacturers can intelligently design dark chocolate to reduce the overall fat content.” [BBC News]

This paper garnered significant public interest with articles quickly published in The Guardian and BBC News as well as many many other media outlets.

The broader context of this work paves the way for new types of low fat food that optimise the mouth-feel (enabled via oral tribology insights) which may help users lose weight without comprimising food perception and taste!

Xolography: No time for layers in medicine and healthcare

With the introduction of the new volumetric 3D printing technique known as Xolography[1], the conventional approach of layer-by-layer printing in additive manufacturing is altered. To harden the resin, it uses two different types of wavelengths and various initiators. In comparison to conventional photopolymerization techniques, this speeds up the process and produces a smoother surface with more material options.

A new company using this technology, Xolo3D, has published a paper in nature [1]. The brief video about this technology is available here Xolography. See the header image which shows The Xcube: Volumetric 3D printer and new photoinitiator from Xolo3D [1].

How it is different from the other 3D photopolymerization techniques?

Xolography is a dual color volumertric 3D printing process and uses the light to cure the photoresin similar to the SLA/DLP printers. However, Xolography employs the novel kind of initiator. When the single wavelength light strikes this initiator, the curing process does not begin. It takes two wavelengths of light (blue and red) to start photopolymerization, and the initiator cures wherever the two wavelengths of light meet.

This has some limitations as well:
⦁ Transparent resins are required (as printing zone is bigger and avoidance of absorption of light is necessary)
⦁ Highly viscous resins (in order to prevent from sinking after they have been printed and to avoid any kind of support structures)

This innovative technology makes printing faster, smoother (no polishing is necessary), and more material possibilities. This technology, specifically bioprinting techniques like printing high-resolution hydrogels, has enormous potential in the medical field.

More interested readers are guided to the nature paper and webinar from the R &D manager of Xolo3D. Webinar by Niklas König

 

 

References:
[1] Regehly M, Garmshausen Y, Reuter M, König NF, Israel E, Kelly DP, Chou CY, Koch K, Asfari B, Hecht S. Xolography for linear volumetric 3D printing. Nature. 2020 Dec;588(7839):620-624. doi: 10.1038/s41586-020-3029-7. Epub 2020 Dec 23. PMID: 33361791.

 

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

Dilesh is researching the Development of 3D-printable, self-lubricated polymer composites with improved wear resistance for total joint replacement at Luleå University of Technology, Sweden.

Can ChatGPT help develop medical devices?

Open AI, an artificial intelligence R&D company, recently launched ChatGPT, an AI based on an optimized language model to interact with humans in a conversational manner. As mentioned on Open AI’s website, once a user has created an online profile, it becomes possible to engage in a dialogue with ChatGPT, which is capable of answering follow-up questions, admitting mistakes, challenging incorrect premises and rejecting inappropriate requests.

For example, when ChatGPT is asked “How can AI improve 3D printing?” and then “Do you have more specific examples for 3D printing in medical applications?” the AI is able to instantly give the answers visible in the image. The AI gathers information to provide relevant insight into possible medical application areas where AI could help humans optimize the current 3D printing process. This dialogue system represents an excellent opportunity to realize the full potential of AI by saving time collecting information and compiling it into written text, although reference checking remains essential.

 

Asking AI (ChatGPT) how AI can improve 3D printing in medical device applications

Open AI’s goal is “to make AI systems more natural and safer to interact with” by using ChatGPT to receive user feedback. Since ChatGPT is capable of answering questions and writing a text on a topic resulting from the collection of information available online, it can be used by students, teachers or scientists for writing purposes. The increasing accessibility and performance of AI will challenge areas that include writing, such as education (homework) or science (publication introductions). Managing the integration of AI into our work processes and setting its limits will likely lead to interesting discussions about the balance between benefits and drawbacks.

 

Learn more about OpenAI and use ChatGPT here.

 

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.

A guide to in vitro testing

Sometimes, designing a suitable in vitro protocol is not an easy task and every biologist knows it. The two most important aspects when you design an experiment are: the research question and the model that you want to use to represent the reality. In my opinion, finding the research question is definitely hard, but not the hardest part. The most difficult part is when you want to artificially reproduce an entire micro/macro-environment in a cell lab. The preferred method would be to just skip complex in vitro testing and go directly in vivo but we, as scientists, are committed to respecting life, including animal life. This is why we spend much of our time and resources developing new methodologies to test different aspect of many biological mechanisms.

The first thing to do when you are trying to develop a good in vitro model is breaking the problem in small little bricks and then analyze them separately. Most of the time you cannot include a lot of parameters at the same time in a single test. Then, one is left with a lot of variables and decisions to set and modify to mimic the real test environment. This could be tricky since nowadays we have a lot of options to choose when you talk about cell culturing. There are a lot of products in the market that could be used for your experiments. This is of course good news, but sometimes this could also be quite confusing. It is not rare that a colleague contacts me to seek advice about cells, media, supplements and so forth.

The good news is that there are a lot of papers that helps other researchers in picking the right methodology, test or products that best suits their needs. Typical in vitro testing problems can be: selecting the right cell line or primary cells, choosing the right culture media both to keep the cells healthy and to mimic the natural environment as closely as possible. Moreover, all of this must obviously meet reality! Everything is feasible on paper, but the transition from a piece of paper to the cell lab is too complex to be imagined in its entirety in advance.

My tips and tricks to create successful in vitro protocol are few and perhaps well-known but maybe they could help someone to find again the right perspective about this. First of all, plan as much as you can but do not skip lab work. This is so important! Always put yourself out there so you will face real problems and you will take real decisions to get rid of them. Secondly, be loyal to your research question and make decisions based only on that. Lastly, while you work with “standard” or “well established” methods always try to improve them. Try to push things to the limit, but don’t try something just because it’s new. Try it only if it makes scientific sense!

 

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

Niccoló is researching Bioimaging of biomaterials and biological characterization of 3D-printed alloys for reconstructive surgery at Uppsala University, Sweden.

 

3D Bioprinted Implants for Critical Size Bone Defects

Header Image: Scheme (A) and image (B) of the FRESH process showing the gel of interest (A. green, B. black) printed in the temporary support gel. After printing layer by layer, the 3D structure is released by melting the support gel.

A critical size bone defect is defined as the absence of a bone segment that would not heal spontaneously and require surgical intervention to make the bone functional again. The exact size and volume of a critical size bone defect depend on the patient and the location, but in most cases refers to a defect that is greater than 1 cm in length and greater than 50% of the circumference of the bone in volume. Critical size bone defects are the result of pathologies or traumatisms such as infections, tumor resections, non-union fractures or accidents and lead to a difficult clinical scenario for the surgeon and the patient. As the bone is not able to insure bone regeneration to fill the gap, several surgical procedures promoting osteogenesis (bone formation) are currently used like the Induced Membrane Technique, Distraction Osteogenesis and autologous (from the patient) grafting. These procedures present several limitations such as multiple surgical interventions, infection, long duration of reconstruction, donor site morbidity. There is an un-meet clinical need for scaffolds supporting bone formation and viable osteointegration in a cost-effective manner while minimizing patient morbidity (complications). 3D printed implants represent a promising alternative currently under investigation in the orthopaedic research field [1].

Within the ETN BioTrib working on orthopaedic implant technology, some projects aim at making progress towards the development of biodegradable scaffolds specific to patients’ bone defects. 3D bioprinting according to a design following the complex internal architecture of bone with collagen (main bone component) and autologous cells would combine interesting features to support bone regeneration while the implant is degraded. However, reaching mechanically stable scaffolds (not collapsing or deforming under their own weight) over several millimeters with good resolution can be hard when printing superimposed layer of soft gels. The emerging FRESH (Freeform Reversible Embedding of Suspended Hydrogels) bioprinting technology, first described in 2015 by Dr. Feinberg’s group, represents a promising approach to overcome this limitation, as collagen is printed into a secondary gel used as a temporary support.

The main advantage is to maintain the intended 3D geometry using biologically relevant soft gels that would collapse if printed in air. Once the 3D structure is FRESH printed, the support gel is discarded through melting while maintaining the stability and resolution of the collagen 3D structure. FRESH scaffolds present limitations encountered in 3D bioprinted scaffolds, namely vascularization of thick scaffolds, and ability to resist loading which is needed for bone implants. FRESH bioprinting of functional implant for critical size bone defects requires further development, but this technology expands the bioprinting possibilities in academia and industry [2].

References
[1] Mayfield, C. K., Ayad, M., Lechtholz-Zey, E., Chen, Y., & Lieberman, J. R. (2022). 3D-Printing for Critical Sized Bone Defects: Current Concepts and Future Directions. Bioengineering, 9(11), 680. https://doi.org/10.3390/bioengineering9110680
[2] Hinton, T. J., Jallerat, Q., Palchesko, R. N., Park, J. H., Grodzicki, M. S., Shue, H. J., Ramadan, M. H., Hudson, A. R., & Feinberg, A. W. (2015). Three-dimensional printing of complex biological structures by freeform reversible embedding of suspended hydrogels. Science Advances, 1(9). https://doi.org/10.1126/sciadv.1500758

 

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.

BioTrib: External Expert Advisory Board Meeting

Great recent External Expert Advisory Board meeting for BioTrib!

Early Stage Researchers provided an overview of the progression in each of the work packages and their own career development.

Erudite conversations, succinct presentations and insightful recommendations from the board. Special thanks to the external advisory members including the Chair, Dr Vishal Borse, Jude Meakin, Sara Manzano, Heather Yates and Lars-Erik Rannar.

Header Image: A sample of the BioTrib personnel present at the EEAB.

Additive Manufacturing in Medical Applications

Additive Manufacturing (AM) is the process of creating an object by building it one layer at a time. It is a sustainable production method that eliminates the need for excess material and unnecessary waste. It can be used to fabricate complex shapes without tooling. The cost of manufacturing with AM is often not cheaper than conventional processing, particularly if the product is designed for mass production. AM processes include VAT photopolymerization, material jetting, material extrusion, binder jetting, powder bed fusion, sheet lamination, and directed energy deposition. These AM processes are briefly explained as follows:

  • VAT photopolymerization: liquid photopolymer in a vat is cured by light, and the material form is liquid.
  • Material jetting: droplets of material are selectively deposited, and the material form is liquid.
  • Material extrusion: material is dispensed through a nozzle in layers, and the material forms are filament, pellets, and paste.
  • Binder jetting: a liquid bonding agent is selectively deposited, and the material form is powder.
  • Powder bed fusion: thermal energy fuses regions of a powder bed, and the material form is powder.
  • Sheet lamination: sheets of material are bonded to form an object, and the material form is sheets.
  • Directed energy deposition: focused thermal energy fuses materials as deposited, and the material forms are powder and wire.

The medical applications of AM are classified as follows:

  1. Medical models: Medical models are based on patient anatomy, and they can be used for preoperative as well as postoperative planning. They are widely used in the craniomaxillofacial area, also for limbs, the spine, and the pelvis. Powder bed fusion, material extrusion, and binder jetting are three AM processes that are usually utilized for medical models.
  2. Implants: Implants are manufactured directly or indirectly by AM to replace damaged or missing tissue. AM is a favorable choice for manufacturing personalized implants. Most of the implants are constructed from metals using the powder bed fusion process. In some cases, polymers and ceramics are utilized to fabricate the implants.
  3. Tools, instruments, and parts for medical devices: Tools, instruments, and parts for medical devices improve clinical operations. Patient-specific dimensions and shapes might be used. Surgical instruments as well as orthodontic appliances can be considered in this classification. The VAT photopolymerization process is often employed to manufacture tools, instruments, and parts for medical devices.
  4. Medical aids, supportive guides, splints, and prostheses: Parts created with AM are external to the body and can be customized. Long-term and postoperative supports, motion guides, fixators, external prostheses, prosthesis sockets, and personalized splints can be taken as examples of this category.
  5. Biomanufacturing: A combination of AM and tissue engineering is considered Biomanufacturing which mostly uses polymers, ceramics, and composites. Porous structures are also utilized that are favorable to attracting cells and cell growth.

Reference:

[1] Salmi, Mika. “Additive manufacturing processes in medical applications.” Materials 14.1 (2021): 191.

 

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

Mahdieh is researching the Design of Self Lubricating Prothesis at ETH Zurich, Switzerland.

Aircrafts and Medicine: an unexpected connection

Sometimes unexpected events occur at unexpected times, providing inspiration for medicine. In this instance, it pertains to ophthalmology, more specifically intraocular lenses, and it occurred during World War II. Intraocular Lenses (IOLs) are optical lenses that can correct refractive defects by being implanted in the eye. IOL-based cataract surgeries are currently one of the most popular and safest surgical procedures performed globally. (Yu, 2018)

The Second World War did, in fact, mark the genuine commencement of the IOL. Harold Ridley was a civilian ophthalmologist, who were operating on Royal Air Force pilots who suffered eye injuries, engaged in aerial combat over the South of England. On August 15, 1940, he underwent 19 surgeries on a pilot, whose Perspex canopy had shattered, sending numerous splinters of poly(methyl methacrylate) (PMMA, Figure 1) into his eyes.

Figure 1. (a) MMA (methyl methacrylate) forms the basis for acrylic IOLs. (b) (PMMA) is a transparent thermoplastic.

He discovered that the PMMA splinters, unlike glass splinters, remained inert in the patient’s eye and that the immune system had not responded to them during the course of the treatment. Ridley came to the realisation that PMMA could be utilised to create artificial lenses that could be inserted into the eye to replace the natural lenses that had been removed during cataract surgery. (Kretz, 2014)

He then, together with the Rayner Optical Company, produced the first IOL (Figure 2) adopting ICI’s Transpex I, a high quality version of PMMA. On November 29, 1949, at St Thomas’ Hospital, London, Ridley performed surgery inserting the first lens into a 42-year-old woman after an extracapsular cataract excision. (Scholtz, 2006)

Figure 2. Scanning electron micrograph of a Ridley intraocular lens made from PMMA

Today, millions of people’s lives have been made better thanks to Ridley’s brilliance. IOLs are now widely used for refractive outcomes improvement throughout clear lens exchange, not just during cataract surgery. The quality of vision following cataract surgery has never been greater in the developed world thanks to the incremental advancements in IOL design.

Take-Home Message: always keep an open mind, you never know where the next important medical discovery might come from!

 

References

Yu, N. F. (2018). State of the art of intraocular lens manufacturing. The International Journal of Advanced Manufacturing Technology, 1103–1130.

Scholtz, S. (2006, September). An Ophthalmic Success Story: The History of IOL Materials. From CRSTEurope: https://crstodayeurope.com/articles/2006-sep/0906_18-php/

Kretz, F. S. (2014, May 19). A Brief History of IOL Materials. From theOphthalmologist.com: https://theophthalmologist.com/subspecialties/a-brief-history-of-iol-materials

 

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

She is studying a PhD in Tribological Characteristics of Nanofibrous Electrospun Materials at ETH Zurich.

Would you accept an organ transplant from an animal donor?

Would you accept an organ transplant from an animal donor? Nature’s recent paper “ Will pigs solve the organ crisis?” [1] sparked this question in my brain. On one hand, animal-grown organs might significantly reduce transplantation waiting times. On the other hand, practical and ethical concerns arise from genetically modified animals, cruelty, organ rejection, and infections.

According to Organ donor, 17 people die on the organ transplant waiting list each day [2]. In the US, more than 100.000 people are waiting for a transplant. Kidney, liver, and heart are the most transplanted organs. Approximately 35.5 thousand transplants were performed between the months of January to October 22 [3]. That means only approximately one in 3 people will receive a much-needed transplant.  These statistics do not reflect the global reality – even in some countries, regional differences may influence the likelihood of a patient getting a needed new organ.

Could animal-grown organs be the solution to long-transplant lines?

Genetic modifications are allowing size-compatible organs, lack of immune rejection, and thus increased lifespans [1]. However, the biggest limitation lies in the increased risk of virus spillover from animals to humans and the presence of endogenous retroviruses that might be harmful to the patient [1]. Polemic issues with human testing on brain-dead patients were also pointed out by the paper [1]. From the animals’ perspective, it is also important to assure that genetic modification does not impart suffering. They must also be treated properly. Although xenografts hold great potential, further testing, development, and regulation are required before we can have an answer to our questions.

Header Image:VCH’s Lions Gate Hospital surgery” by Vancouver Coastal Health is licensed under CC BY-NC-ND 2.0.  

 

REFERENCES

[1] Reardon, S. (2022). Will pigs solve the organ crisis? The future of animal-to-human transplants. In Nature (Vol. 611, Issue 7937, pp. 654–656). Springer Science and Business Media LLC. z

[2] Health Resources & services. Organ donation statistics. Available at: <https://www.organdonor.gov/learn/organ-donation-statistics> Accessed 24 Nov. 22

[3] Organ procurement & transplantation network. Data. Available at: <https://optn.transplant.hrsa.gov/data/> Accessed 24 Nov 22.  

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.  

Tribology & Biotribology

Tribology could be considered the most interdisciplinary subject known compared with other engineering or physical science disciplines. Overall, it is related to Mechanical Engineering, Materials Science Engineering, Chemistry, Physics, Mathematics, as well as Biology. Based on the Greek root “tribos”, meaning to rub, tribology is the study of surfaces that have relative motions. Tribological considerations, such as surface roughness, material compatibility, and contact stresses, should be noticed in the design, manufacture, and use of anything that is in contact with another object. The applications of tribology include individual components (gears, bearings, brakes, etc.), assemblies (engines, pocket watches, etc.), manufacturing processes (rolling, turning, grinding, stamping, etc.), construction (mine slurry pumps, oil drilling rig, excavator, etc.), and natural phenomena (water/wind erosion, plate tectonics, etc.). The commonality between these applications is that two different surfaces are in contact or have a relative motion. Two aspects of these surfaces, including physical (surface roughness) and chemical (intervening layers), should be taken into consideration due to their vital roles in tribology.

Overlapping key fields of study in Tribology

Tribology is mainly composed of three fields, namely friction, wear, and lubrication. These terms can be defined as follows:

Friction: Friction is the resistance to relative motion between two bodies in contact. There are two microscopic forces, called molecular adhesion and mechanical abrasion, between these two objects in touch. Molecular adhesion includes electrostatic, Van der Waals, as well as metallic bonds while mechanical abrasion comprises elastic, plastic, and viscoelastic deformations. Friction can be measured by the coefficient of friction which is a constant of proportionality.

Wear: Wear is the removal or displacement of material from one body when subjected to contact and relative motion with another body. Like friction, wear is a system property and not a material property. There are several distinct wear regimes, including abrasive wear, adhesive wear, fretting corrosion, erosive wear, rolling contact fatigue, and tribo-corrosion. Some of these regimes can operate simultaneously or sequentially. The wear rate significantly changes according to the wear mode which is a function of the Tribosystem.

Lubrication: Lubrication is the use of a fluid to minimize friction and wear. The critical roles of a lubricant are to reduce friction, prevent or minimize wear, transport debris away from the interface, and provide cooling. Different lubrication regimes, including boundary lubrication, mixed lubrication, and fluid film lubrication, are determined based on the fluid film thickness. These regimes are also described by the Stribeck curve.

The expression of “Biotribology” was first defined by Dowson in 1970, which considers all aspects of tribology associated with biological systems, particularly the synovial joints and joint replacements. Biotribology pertains to friction, wear, and lubrication at biological interfaces. Studying the biotribology of the natural synovial joints helps us to better understand the joints’ function as well as the development of related diseases, and to figure out what kind of medical interventions are required. This could contribute to enhancing the quality of life of patients suffering from diseases associated with synovial joints.

 

Learn more at Tribology 101 – Introduction to the Basics of Tribology | Dr. Arun Sikder, Bruker USA, 2019

 

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

Mahdieh is researching the Design of Self Lubricating Prothesis at ETH Zurich, Switzerland.

Industrial secondment at SWERIM AB

Since August, Vidhiaza and Giulio have been going to SWERIM AB as part of their BioTrib secondment plans. SWERIM AB is an institute that conducts industrial research and metals development. They have a location in Stockholm, just an hour away by train from Uppsala. At SWERIM AB, Vidhiaza and Giulio conduct experiments with the powder that they use for additive manufacturing. This brings a lot of synergy to their research as Uppsala University does not have the instruments to perform powder research.

Below, Vidhiaza is pictured with a spreadability tester in the SWERIM AB powder lab. This equipment can mimic the movement of a powder recoater that exists in an additive manufacturing machine to produce a layer of powder. Vidhiaza and Giulio use this machine to check and predict if their powder will be readily spreadable during the AM process, i.e., the powder produces a nice, dense layer.

Here Giulio is pictured with a setup for powder flowability measurements. SWERIM AB powder lab has different set ups for powder flowability according to different standards. Flowability is also an exciting and relevant powder property to AM process because it is directly related to how well an AM machine can dispense the powder.


Overall, the secondment at SWERIM AB has been very educative for Vidhiaza and Giulio, and it definitely enriches their research experience as BioTrib ESRs!

 

This article was written by Giulio Cavaliere as part of a series articles curated by BioTrib’s Early Stage Researchers.

Giulio Cavaliere is investigating Additively manufactured biodegradable alloys for bone replacement at Uppsala University, Sweden.

 

 

 

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

Vidhiaza is researching the Development of Development of 3D-printed gradient alloys for joint implant component at Uppsala University, Sweden

Filippo Ganna breaks the hour record on a 3D printed Pinarello bike

Header Image: 3D Printed Pinarello Bolide F HR 3D bike [1].

The ultimate benchmark for a cyclist, 60 minutes alone in a velodrome, suffering and draining any drop of energy left in the body. It’s the Hour record, the longest distance cycled in an hour from a stationary position.

From 1876, when the American Frank Dodds rode 26.508 km on a penny-farthing, the hour record has been held by the greatest cyclists in history from Fausto Coppi to Eddy Merckx, from Francesco Moser to Bradley Wiggins.

But the record is not just an incredible demonstration of human strength and endurance, it’s also the place to test and develop new cutting-edge technologies. In 1984 Francesco Moser smashed the record established 12 years before by Eddy Merckx using a revolutionary bike with composite lenticular wheels and a very peculiar frame shape.

Rider on Pinarello Bolide F HR 3D Bike [1].
38 years later the hour record is once again Italian, Filippo Ganna cycled 56,792 Km in an hour in the Swiss velodrome of Grenchen. The bike he rode is almost as impressive as the record itself. The Pinarello Bolide F HR 3D was the first metal 3D-printed bike. The company used a high permeance aluminum alloy (scalalloy) 3D printed in an EOS M400, an industrial scale powder bed fusion (PBF) system. This was a proof of concept and used all the advantages of 3D printing over traditional manufacturing techniques. Firstly, the flexibility in design, the scale-like pattern on the seat tube greatly helps with the aerodynamic, but this is only obtainable through additive manufacturing. But also, fast prototyping allows customizing the frame to the need of any individual athlete without the need of realizing expensive and time-consuming mold for carbon fiber frames.

 

References

[1] “Bolide F HR 3D | En | Pinarello Global.” Accessed October 21, 2022. https://pinarello.com/global/en/bikes/road/competition/bolide-f-hr-3d/bolide-f-1.

 

This article was written by Giulio Cavaliere as part of a series articles curated by BioTrib’s Early Stage Researchers.

Giulio Cavaliere is investigating Additively manufactured biodegradable alloys for bone replacement at Uppsala University, Sweden.