Tissue Engineering for Articular Cartilage Regeneration

Light micrograph of hyaline cartilage

Articular cartilage is a living material composed of a relatively small number of cells known as chondrocytes surrounded by a multicomponent matrix. Mechanically, articular cartilage is a composite of materials with widely differing properties. Approximately 70 to 85% of the weight of the whole tissue is water. The remainder of the tissue is composed primarily of proteoglycans and collagen. Proteoglycans consist of a protein core to which glycosaminoglycans (chondroitin sulfate and keratan sulfate) are attached to form a bottlebrush-like structure.

The structure of articular cartilage is often described in terms of four zones between the articular surface and the subchondral bone: the surface or superficial tangential zone, the intermediate or middle zone, the deep or radiate zone, and the calcified zone.

Currently, the most used techniques for articular cartilage regeneration are microfracture (MF), osteochondral autologous transplantation (OAT), osteochondral allograft transplantation (OCA), particulate articular cartilage implantation (PACI), and autologous chondrocyte implantation (ACI). However, these methods have limitations including calcification, formation of transient fibrocartilaginous tissue, and the low capacity of binding to surrounding normal cartilage [1, 2]. Therefore, scaffolds with improved bulk mechanical properties could increase the efficacy of treatment and promote an earlier return to normal activity.

In recent years, tissue engineering technology has been considered the most promising method for regenerating the articular cartilage [3] [4].

In tissue engineering applications, biomaterial scaffolds play animportant role in providing a 3D environment that supports cellgrowth, matrix deposition, and tissue regeneration. An ideal tissue engineering scaffold should meet several important criteria:

  1. Be biocompatible, minimizing local tissue reactions andmaximizing cell growth and tissue integration.
  2. Be biodegradable with good absorption rate, providing support for early cell proliferation and allows for gradualdegradation after the formation of new tissue.
  3. Have adequate porosity and interconnectivity to allow cellmigration and efficient exchange of nutrients and waste.
  4. Possess suitable mechanical properties to support tissue growthunder natural mechanical loads.


To date, many biomaterial scaffolds have been extensively studied, including natural polymers extracted from living organisms and synthetic materials derived from various chemical processes used intissue repair and regeneration.

Natural biomaterials are popular as scaffolds for cartilage repair and regeneration due to their excellent biocompatibility for cell adhesion and differentiation. In particular, natural scaffolds used in tissue engineering of articular cartilage include carbohydrate-based hyaluronic acid, agarose, alginate, chitosan, and protein-based collagen or fibrin glues.

Due to its ease of fabrication and chemical modification, excellent biocompatibility, high versatility, suitable mechanical properties and controllable biodegradability, synthetic polymers are currently being investigated for their potential as a scaffold for cartilage tissue. The most common synthetic polymers for cartilage engineering scaffolds are polylactic acid (PLA, present in both L and D forms), polyglycolicacid (PGA), and its copolymer poly-lactic-co- Glycolic acid (PLGA).

Conventional natural or synthetic scaffolds still need to be improved to achieve better biocompatibility and functional properties for cartilage regeneration. Because the size of native cartilage tissue is only nanometers, and chondrocytes directly interact with nanostructured ECM, the biomimetic properties and excellent physicochemical properties of nanomaterials are essential for chondrocyte growth. [5].

Solution electrospinning (SES) is a technique that allows the production of nanofibrous scaffolds and allows for the tuning of the 3D scaffolds by changing the fiber diameter and scaffold porosity. The process consists of a pump that pushes out, through a metal needle (spinneret), the polymer solution, inserted in a syringe. The presence of a high voltage source that energizes the polymer solution causes formation of a conical jet (Taylor cone) which is then drawn into a fiber by electrostatic repulsion [5] [6]. The resulting fibers are deposited on a flat or tubular electrode (collector). The thin electrospun fibers range from a few hundred nanometers to a few micrometers and are suitable candidates to mimic the structure of the natural extracellular matrix (ECM) as they can stimulate cell ingrowth and proliferation [7].

Advances in fabrication methods have solved the scalability problem and enabled the development of porous structures that allow long-term cell invasion and growth. Despite all these advantages, electrospun scaffolds have yet to be fully evaluated in preclinical models and clinical settings, hindering widespread acceptance of this breakthrough technology in biomedicine [8]


[1] C. Vinatier and J. Guicheux, “Cartilage tissue engineering: From biomaterials and stem cells to osteoarthritis treatments,” Annals of Physical and Rehabilitation Medicine, vol. 59, pp. 139 – 144, 2016.

[2] W. Wei, Y. Maa, X. Yao, W. Zhou, X. Wang, L. Chenglin, J. Lin, Q. He, S. Leptihna and H. Ouyang, “Advanced hydrogels for the repair of cartilage defects and regeneration,” Bioactive Materials, vol. 6, p. 998–1011, 2013.

[3] S. Jiang, W. Guo, G. Tian, X. Luo, L. Peng, S. Liu, X. Sui, Q. Guo and X. Li, “Clinical Application Status of Articular Cartilage Regeneration Techniques: Tissue-Engineered Cartilage Brings New Hope,” Stem Cells International, 2020.

[4] A. Martín, H. Zlotnick, J. Carey and R. Mauck, “Merging therapies for cartilage regeneration in currently excluded ‘red knee’ populations,” Nature Partner Journal Regenerative Medicine, vol. 4, 2019.

[5] N. Maurmann, S. L and P. P, “Electrospun and Electrosprayed Scaffolds for Tissue Engineering,” Cutting-Edge Enabling Technologies for Regenerative Medicine, pp. 79 – 100, 2018.

[6] R. Soares and al., “Electrospinning and electrospray of bio-based and natural polymers for biomaterials development,” Mater Sci Eng C Mater Biol Appl, pp. 969-982, 2018.

[7] D. Alexeev and al., “Electrospun biodegradable poly(epsilon-caprolactone) membranes for annulus fibrosus repair: Long-term material stability and mechanical competence,” JOR Spine, vol. 1, 2021.

[8] E. Z. D. Yilmaz, “Electrospun Polymers in Cartilage Engineering—State of Play,” Front. Bioeng. Biotechnol., 2020.

[9] L. H. J. A. K. Zhang, “The Role of Tissue Engineering in Articular Cartilage Repair and Regeneration,” NIH Public Access, 2009.


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.

For Patients: A To-Do List Before Total Joint Replacement

Joint replacement surgery is an effective procedure that can considerably improve your quality of life. However, before you undergo surgery, there are a few things you should do to prepare. Here is a to-do list to help you get ready for your joint replacement surgery:

  1. Meet with your surgeon: Before the surgery, you will have a consultation with your surgeon. During this meeting, your surgeon will explain the procedure and answer any questions you may have.
  2. Get medical clearance: Your surgeon will likely require that you get medical clearance from your primary care physician before the surgery. This will ensure that you are healthy enough to undergo the procedure.
  3. Stop smoking: If you smoke, your surgeon will likely ask you to quit before the surgery. This is because smoking can slow down the healing process and increase the risk of complications.
  4. Arrange for help: Joint replacement surgery requires a period of recovery, so you will need someone to help you with daily tasks during this time. Make arrangements for someone to help you before the surgery.
  5. Gather necessary items: You will need to have certain items on hand for your recovery, such as comfortable clothing, slippers, and a raised toilet seat. Make sure you have these items before the surgery.
  6. Prepare your home: You will need to prepare your home for your recovery by making it easy to navigate and removing any potential hazards.
  7. Stock up on supplies: You will need certain supplies for your recovery, such as pain medication and ice packs. Make sure you have these items before the surgery.
  8. Get a good night’s sleep: The night before the surgery, make sure you get a good night’s sleep to ensure you are well-rested and ready for the procedure.
  9. Eat a healthy diet: Eating a healthy diet before surgery can help to improve your overall health and speed up your recovery.
  10. Avoid certain medications: Your surgeon will likely advise you to avoid certain medications, such as blood thinners, before the surgery.
  11. Follow instructions: Be sure to follow all instructions given to you by your surgeon before the surgery.
  12. Take your pre-op medications: You will be given certain medications to take before the surgery. Be sure to take them as directed.
  13. Do your exercises: Your surgeon may give you exercises to do before the surgery to help prepare your body for the procedure.
  14. Get your affairs in order: Before the surgery, take care of any important business or personal matters.
  15. Keep your loved ones informed: Keep your loved ones informed of your surgery and recovery progress.
  16. Pack a bag: Pack a bag with the essentials you will need during your hospital stay.
  17. Prepare for transportation: Arrange for transportation to and from the hospital.
  18. Keep your ID and Insurance card handy: Keep your ID and Insurance card handy for the day of the surgery
  19. Keep your surgeon updated: Keep your surgeon updated of any changes in your health condition before the surgery
  20. Read the patient manual: Read the patient manual provided by the hospital and be prepared for the pre-op process
  21. Get your finances in order: Get your finances in order and make sure you understand the cost of the surgery and any possible additional cost
  22. Set realistic expectations: Be realistic about the recovery process and the results of the surgery
  23. Follow post-op instructions: Follow all post-op instructions given by your surgeon

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

Edona’s research is focussing on Understanding the Nature, Origin and Degradation of Implant Debris at the University of Leeds, UK

Post-joint replacement progressions – Biologic and regenerative therapy

Biologic and regenerative therapies are relatively new research areas in the field of joint replacement surgery. These therapies involve using biological materials, such as stem cells and growth factors, to enhance the healing process and improve the longevity of the implant.

One of the main benefits of biological and regenerative therapies is that they can potentially reduce inflammation and promote the formation of new tissue, leading to faster healing and improved joint replacement function.

Stem cells, for example, have the ability to differentiate into various types of cells and have been shown to have regenerative properties. Growth factors are substances that stimulate cell growth, proliferation and differentiation and have been used to enhance the healing process.

Another benefit is that biological and regenerative therapies can potentially reduce the wear and tear on the implant, which can help to prolong its lifespan.

However, it’s important to note that biological and regenerative therapies are still considered experimental and not widely available. Nevertheless, there are ongoing studies and clinical trials to evaluate the safety and efficacy of these therapies in joint replacement surgery.

It’s also essential to consult with your surgeon to understand if this approach is appropriate for you and if it is available in your area.

Overall, the use of biological and regenerative therapies has the potential to enhance the healing process and improve the longevity of the implant, but more research is needed to understand the benefits and risks of these therapies fully.


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

Edona’s research is focussing on Understanding the Nature, Origin and Degradation of Implant Debris at the University of Leeds, UK

Degradation of a metal-on-polyethylene (MoP) hip prosthesis: Preclinical outcomes

According to NJR (2021) report, UK continues to have the largest use of metal on polymer (MoP) hip replacements. An increasing number of the prevalence of revision surgery caused by adverse local tissue reaction in MoP THRs has recently been reported which is 3.2% at a mean follow-up of over 10 years (Hussey and McGrory, 2017). The issues are associated with debris/ion generated due to combined action of wear and corrosion termed as tribocorrosion/biotribocorrosion. As a result, the impact of these influential factors need to be assessed prior to implantation.

There are numbers of research questions related to hip implant failure which could be addressed during this preclinical testing using modern hip simulator. Such as, which interfaces are more prone to corrosion degradation? What is the tribocorrosion mechanism? etc. Often the results from preclinical testing showed deviance from clinical outcomes due to various reasons including testing protocol that is required to follow.

To address the above questions, Yang et al. (2022) have conducted an experiment under walking gait cycles to investigate the long-term biotribocorrosion at the MoP THR. His study revealed that the modular taper/trunnion junction was the main cause of MoP THR biotribocorrosion, not the bearing surfaces. The presence of tribochemical reaction layer on the surface proved the hypothesis as shown in the above figure (taken from the Yang et al. (2022) article and modified). The formation of this tribolayer could be impacted by number of ways. Even the changing of serum could have significant effect on the corrosion rate which may lead to poor prediction for clinical application. One of the limitation of his study is the lower number of loading cycles than recommended by ISO which need to be dealt in future.


Featured header image: Graphical abstract produced from figures taken from Yang et al. (2022)


Hussey D K, McGrory B J. Ten-year cross-sectional study of mechanically assisted crevice corrosion in 1,352 consecutive patients with metal-on-polyethylene total hip arthroplasty. J Arthroplasty 32(8): 2546–2551 (2017)

National Joint Registry 18th Annual Report 2021, https://www.njrcentre.org.uk/

Yang, S., Pu, J., Zhang, X., Zhang, Y., Cui, W., Xie, F., … & Jin, Z. (2022). A preliminary experimental investigation on the biotribocorrosion of a metal-on-polyethylene hip prosthesis in a hip simulator. Friction, 1-13.  


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

Raihan is researching In-situ Measurement of Nano-scale Wear Utilising Advanced Sensors at the University of Leeds, UK.        

Porosity control and influence in 3D bioprinted scaffolds

Header Image: Schematic representation of scaffolds characterized by three different lay-down patterns. (a) 0◦/90◦. (b) 0◦/60◦/120◦. (c) 0◦/45◦/90◦/135◦. [1]

The main objective of 3D bioprinting is to recreate human tissues with the same mechanical, structural and biological properties as the corresponding native tissue, in order to solve the problems associated with conventional transplantation techniques (donor site morbidity, organ shortage, etc.). For this purpose, different cell types combined with different biomaterials have been bioprinted according to specific models, but obtaining a 3D scaffold with the desired properties remains a challenge.

The advantage of 3D bioprinting over conventional scaffold fabrication techniques is the ability to control the 3D architecture of scaffolds through parameters such as pore size and geometry. Pore size and shape influence the resulting mechanical properties as well as cell behavior and tissue growth over time. Domingos et al. showed that for a lay down pattern of 0◦/90◦ (filament orientation between layers) with different pore sizes, poly(ε-caprolactone) scaffolds with smaller pores exhibit significantly higher stiffness under compressive conditions, which is an important property in applications such as bone tissue engineering. For different pore shapes with the following lay down pattern: 0◦/90◦, 0◦/60◦/120◦ and 0◦/45◦/90◦/135◦ (see figure) and the same porosity, the increasing number of angles between the filaments of the different layers leads to an increase in the deformability of the construct under compressive conditions.

Regarding the influence of architecture on cell behavior, viability and proliferation of human mesenchymal stem cells (hMSCs) were studied for 21 days and showed that larger pores with a lay down pattern of 0◦/90◦ improve viability and proliferation.



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.

Poly(electrolytes) applications for friction reduction

Header image: schematic of a polymer brush interface. 

Polyelectrolytes are charged polymers with special hydration properties. They are present in our bodies as sulfated glycosaminoglycans (e.g., chondroitin sulfate) and play an important role in lubrication and tissue homeostasis. Tissue engineering novelties are trying to bring the best out of the synthetic world, by mimicking the special properties of these electrolytes, grafted to all kinds of materials [1].

Kwon and Gong [2] studied the effect of negatively charged biomimetic polyelectrolytes for multiple applications, including low friction. Pavoor et al. [1] show the effects of the friction of grafting negatively poly(acrylic acid) and positively charged poly(allylamine hydrochloride) on ultra-high molecular weight polyethylene. Qin et al. [3] showed that the polydopamine-assisted immobilization of chitosan (net positive charge) can improve the biocompatibility and tribological properties of Cobalt Cromium implants. They demonstrated a tenfold decrease in the coefficient of friction upon brush-grafting.  


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.





[1]          P.V. Pavoor, B.P. Gearing, O. Muratoglu, R.E. Cohen, A. Bellare, Wear reduction of orthopaedic bearing surfaces using polyelectrolyte multilayer nanocoatings, Biomaterials. 27 (2006) 1527–1533. https://doi.org/10.1016/j.biomaterials.2005.08.022.

[2]          H.J. Kwon, J.P. Gong, Negatively charged polyelectrolyte gels as bio-tissue model system and for biomedical application, Current Opinion in Colloid & Interface Science. 11 (2006) 345–350. https://doi.org/10.1016/j.cocis.2006.09.006.

[3]          L. Qin, H. Sun, M. Hafezi, Y. Zhang, Polydopamine-Assisted Immobilization of Chitosan Brushes on a Textured CoCrMo Alloy to Improve its Tribology and Biocompatibility, Materials. 12 (2019) 3014. https://doi.org/10.3390/ma12183014.    

Space and Medicine: an unexpected connection

So many lives have been saved thanks to the Hubble Telescope.

It sounds incredible but, among the tens of thousands of examples of technologies and their positive impacts on human lives, there is one story that reminds us how remarkable space exploration can be. An extraordinary story that begins with a colossal failure.

Mammography with arrows highlighting artefacts indicative of breast cancer

The image shows a mammography, and the arrows indicate microcalcifications, which are sometimes the telltale sign of breast cancer.

It was possible to detect those microcalcifications sharply because of the legendary Hubble telescope. You may be wondering how.

At the beginning of its usage, the first Hubble images were blurry because the primary mirror had been over-smoothed and flattened 2 thousandths of a millimeter too much. It is roughly one-fiftieth the thickness of a sheet of paper, yet thick enough to bounce the incident light slightly out of focus. Thus, various techniques were developed to increase the dynamic range and spatial resolution of Hubble’s initially blurred images before detecting the true cause and repairing it.

These techniques had also been applied to medicine and, in this case, allowed doctors to detect calcifications in the female breast that were smaller than before and would otherwise have gone undetected, resulting in earlier diagnosis and treatment, which is critical as the earlier the cancer is detected and treated, the greater the chances of a patient making a full recovery.

This is only one of many, many, endless instances of how space research can improve our lives.

Furthermore, this is an excellent example of how, even when a project appears to fall short of its goals or is deemed a failure, the spillover effects on the daily lives of human beings can be enormous.

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.

Ben Clegg – Best Oral Presentation Prize

A few weeks ago I had the pleasure of presenting and attending at the conference for the Swedish Society of Biomechanics in Stockholm.

This was my first networking event outside the BioTrib consortium, so it was a great chance and experience to meet fellow colleagues working in the medical engineering field. The first day was a PhD and Post doctoral event enabling us to meet and chat with present and future associates. The following two days composed of engaging presentations and posters.

And I am honoured to have received the award for the prize of Best Oral Presentation! Titled: Biocompatibilty of 3D printed Polymers for use in total joint replacements.

I am looking forward to future conferences and networking events to present my forthcoming work and meet up with new friends and collaborators. I would like to thank Luleå University of Technology, the BioTrib consortium and Professor Nazanin Emami for providing me with the platform and opportunity to present my work and help promote myself in the field of Medical Engineering.

I thank you for taking the time to read this

Ben Clegg

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.

EFORT 2022

The European Federation of National Associations of Orthopaedics and Traumatology (EFORT) recently hosted its 23rd Congress in Lisbon, Portugal. This years main theme was Modern Patient Needs – Challenges and Solutions In Orthopaedics and Trauma.

PhD student Rob Elkington along with NU-SPINE Early Stage Researchers Beril Yenigul and Kaushikk Iyer all attended to present their orthopaedic biotribology projects to one of Europes largest meetings of knee, hip, and spine surgeons and researchers.

Kaushikk Iyer presented his ongoing research work which demonstrates the development of a novel portable benchtop setup that act as a representative to an orthopaedic joint wear simulator used as a pre-clinical evaluation tool for the testing of spine, hip and knee prostheses. Using Hardware-in-the-Loop (HiL) simulation, advanced control algorithms can be designed and tested rigorously and rapidly on the setup before its deployment into the joint wear simulator to test profiles of ISO standards and beyond that represent daily-living activities of patients.

Rob Elkington presented his poster on ‘Biomimetic PEEK Surfaces For Cartilage Preserving Focal Resurfacing’ which employs novel highly lubricious polymer brush systems optimised to interface with cartilage and preserve healthy tissue for minimally invasive focal cartilage repairs and hemiarthroplasty to delay and mitigate the need for total joint replacements.

Beril presented her poster on the ‘Design of Facet Joint Resurfacing Bearings for Tribological Testing Purposes’ which showcases a new paradigm in preclinical testing for facet joint implants in a custom built simulator.

Header Image: Kaushikk Iyer, Rob Elkington, Beril Yenigul who are all studying PhDs in Medical Engineering at the University of Leeds.

Super Innovation in Uppsala

Uppsala University and its Innovation hub have an enviable record of translating high-end science and engineering to the wider sector, with a few examples of this excellence provided here. The Uppsala Innovation Centre has been ranked in the global top five and has an extensive list of business start ups.

This article explains the role and services provide by Uppsala University Innovation and the support provided to students and researchers.  Importantly, the advisors have industrial experience which allows them to truly span the divide between academia and the commercial sector and can better identify the barriers and opportunities for the transfer of knowledge between sectors. 

Prof Cecilia Persson

Prof Cecilia Persson at Uppsala University, a BioTrib scientist in charge, has worked with Uppsala Innovation and the Innovation Centre closely, developing her new bone cement which will reduce the adverse effects of the current generation of injectables used to treat spinal fractures.

Controlling wear

Demand for total joint replacements in the UK continues to soar, driven by an aging population and an increasing number of younger patients undergoing these procedures.

Total knee replacement (TKR) operations are one of the most common surgical procedures globally with 2.6 million performed each year. Components have a limited life of approximately 15 years and in some cases earlier than expected replacement is required due to excessive wear. There are also additional serious concerns as wear debris can cause adverse reactions such as osteolysis, and soft tissue lesions.  The increasing implant rates and the burgeoning healthcare costs emphasize the need for research to improve implant function and longevity to avoid the need for expensive revision surgeries.

Video highlighting the wear mechanisms of all additively manufactured specimen types

Wear control, which relies on understanding the mechanisms of wear, is crucial in preserving the life of mechanical components and reducing costs. Additive manufacturing (AM) techniques can produce parts with tailored microstructure, however, little has been done to understand how this impacts the mechanisms of wear. In this paper Dr Myant and colleagues study the impact build orientation can have on initial grain arrangement and crystal orientation on the wear mechanisms of austenitic stainless steel in dry sliding contact.

Read more: Bahshwan, M., Myant, C. W., Reddyhoff, T., & Pham, M. S. (2020). The role of microstructure on wear mechanisms and anisotropy of additively manufactured 316L stainless steel in dry slidingMaterials & Design196, 109076.

Header figure: Graphical abstract of the Bahshwan research paper.

Transient mixed lubrication model of the human knee implant

Fantastic paper (Transient mixed lubrication model of the human knee implant) from Rob Hewson’s Group at Imperial outlining a computational approach to implant design in terms of the biotribology of knee replacements. Crucially, the investigation uses real-world implant geometries and a statistical description of the surface roughness. Interestingly the model predicts that, under the motion and loading cycles from the standard ISO 14243-3, the implant can demonstrate elastohydrodynamic, mixed and boundary lubrication.

Pressure distribution (in MPa) mapped onto the tibial insert at (a) 2% of the ISO gait cycle, (b) 48% of the ISO gait cycle, (c) 84% of the ISO gait cycle.

The paper was published in a special issue of the Journal ‘Biosurface and Biotribology’ in celebration of the life of Prof Duncan Dowson who, more than anyone, made an outstanding contribution to Biotribology especially from a Leeds perspective.

Image from Butt, H, Nissim, L, Gao, L et al. (3 more authors) (2021) Transient mixed lubrication model of the human knee implant. Biosurface and Biotribology. ISSN 2405-4518

Women living with HIV – carrying the burden of the pandemic.

Source: Sophia Forum – We are still here – accessed 25-10-21

All groups affected by HIV should have access to appropriate care and the opportunity to, for instance, enter clinical trials and access innovative treatments. A recent editorial noted the mismatch between those PLWH that were recruited to clinical trials (overrepresentation of young white males) and those seen in the general population (a more heterogeneric demography). Women have been severely underrepresented in many areas of HIV treatment and care including inclusion in research. This appears to be an ongoing issue across the HIV landscape with alternative approaches required to allow both access and opportunity in advancing care and its underpinning research. This is essential as in the UK a third of people living with HIV are women and globally the figure stands at fifty percent and it is incumbent on everyone that the right interventions are utilised in this as well as any other community. This is particularly important where intersectional issues make marginalisation and stigma even more challenging.  The near-invisibility of WLWH is not a recent phenomenon but one that has existed from the early 80s when HIV came to the fore and the public’s attention.  This is one legacy that the community needs to overcome and as Jacqui Stevenson says:

No more excuses: Making HIV research work for women. (Sophia Forum)

Other marginalised groups such as those from BAME backgrounds, whilst being disproportionately affected, were also largely excluded from trials and medical care more generally.

As ART has produced improved outcomes in terms of life expectancy, the demographics of people living with HIV has changed radically. A significant number of PLWH including women have a life expectancy similar to that found in the general population.  However, there are disparities between groups (see, for instance, Solomon et al 2020) and a general reduction in quality of life for PLWH due to the onset of a range of geriatric syndromes a decade or more earlier with ongoing discrimination. This has been emphasised recently by ongoing research and advocacy by Jacqui Stevenson who has studied WLWH growing older. The outcomes of the research provide eight asks to improve the lives of WLWH.

Advice for women and HIV including using PrEP can be found at:

Validation and Verification

Collectively, verification and validation are a cornerstone of many areas of research, none more so that in engineering and the physical sciences. Yet many early stage researchers have yet to appreciate their definitions or fully understand the signficance of these activities.  William Morales’, blog provides a brief introduction to Device Design Verification and Validation – useful for those just beginning in their careers in the MedTech arena or indeed anyone who needs a quick refresher.  However, there is still of lot of discussion about the use of the terms particulary between fields as there maybe nuances or historical context that means the defintions deviate – for instance the article at ResearchGate by Ryan and Wheatcroft (2017).  Simple defintions may employ something along the lines of:

  • verification - am I building something right
  • validation - am I building the right something

Software engineering, an increasingly important aspect of medical devices, especially through the rise of in situ/in vivo monitoring, has it owns definitions. Sargent defines the processes by which a researcher can V&V computational simulations whilst Viceconti et al (2021) discuss V&V for in silico trials.

Excellent paper from the Nu-Spine ETN – Congratulations to Seung and co-authors!

Seung Hun Lee and colleagues at ETH Zurich have recently published a peer reviewed paper “Comprehensive in vitro Comparison of Cellular and Osteogenic Response to Alternative Biomaterials for Spinal Implants” in Materials Science and Engineering: C. The article explored the effects of silicon nitride (SN) in terms of cell proliferation, mineralization and osteogenesis, all of which were deemed positive with respect to the effects of other materials including Ti and PEEK. A similar result to that of SiN was found for zirconia toughened alumina. Further, the paper demonstrates the potential of surface texturing in enhancing the osteogenic capacity of this material. The graphical abstract for the paper can be found below.

CC License – NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0).
Seunghun S. Lee, Stephanie Huber, Stephen J. Ferguson,
Comprehensive in vitro comparison of cellular and osteogenic response to alternative biomaterials for spinal implants,
Materials Science and Engineering: C, Volume 127, 2021, 112251, ISSN 0928-4931, https://doi.org/10.1016/j.msec.2021.112251.