In the sensing and sensors lecture, we were shown an example of a prosthetic limb in 2021 with haptics responsive enough that a blindfolded 85-year-old could pick up a hollow eggshell without damaging it¹.

This really made me think about the functions you’d need to replicate in a prosthetic arm beyond it being just an appendage for it to fulfill all the roles of the lost limb. I’d only come across haptics being used to extend a user’s ‘self’ in videogame hardware, but with some reflection and research (including on WW2 planes using haptics to forewarn pilots of stalls²) it made sense that the device increasingly becomes an extension of the user with improvements to effective information flow.

So what other sensations are there to improve this link? What other advancements have there been? The sense that immediately comes to mind is temperature, but following that, pain. Pain and discomfort naturally protect us from harm, driving you to avoid potential injury.

In 2018, researchers at Johns Hopkins’ University displayed an electronic synthetic skin called “e-dermis”. A structure of rubber and fabric with sensor “nerve endings” could interact with peripheral nerves of amputees, feeding back curvature and sharpness as “touch” and “pain” respectively. The e-dermis can be implemented on existing prosthetics, enabling users to tell whether they were holding a sharp or smooth object³.

Later in 2020, RMIT University (Royal Melbourne Institute of Technology) developed another electronic synthetic silicone skin. Vanadium oxide’s electronic behaviour changes in response to temperatures above 65˚C, creating a temperature trigger when integrated into the “skin” for pain decision making. Researchers suggested potential applications in non-invasive skin-grafts upon further development, with the “brain-mimicking circuit” having adjustable thresholds to modify sensitivity⁴.

For anyone reading on these advancements there’s a point that probably stands out though. Do the advantages of simulated pain outweigh the discomfort a prosthetic could inflict on the user when the sensor is on a repairable part?

“After many years, I felt my hand, as if a hollow shell got filled with life again,”-Anonymous principal volunteer tester³.

When implementing the “e-dermis”, stimuli produced by the synthetic skin matched sensations in users’ phantom limbs. Additionally, interaction with peripheral nerves is increasingly well documented to reduce phantom limb pain^5,6,7. If reactive pain and sensory feedback can reduce persistent phantom limb pain in amputees, improving brain body mapping for prostheses, the very pain and discomfort we want to avoid could act to unify prosthetic and person.

I was also curious what advancements in sensory prosthetics could do for those paralysed by extension. A 2025 study by researchers at the University of Chicago⁸ worked with individuals with spinal cord injuries. Electrodes were implanted into the sensory and motor regions of the brain, allowing not only control of a robotic arm and hand, but sensation through it. Subjects could feel edges, shapes and movement through their connection to the robotic arm.

Amazingly, subjects had such good control of the limb they could even drive cars (in simulation).

The development of sensation in prosthetics is so much further than I realised, where else could these technologies go? Where else might they end up?  If pain, touch, and temperature feedback can be integrated into artificial limbs, could future developments allow individuals to experience a completely artificial yet fully sensory body?

References

• ¹ Wong, W. G., 2021, Bionic Hand Provides Strength and Haptic Feedback, Medical Design, Machine Design, available at: https://www.machinedesign.com/medical-design/video/21174228/bionic-hand-provides-strength-and-haptic-feedback accessed 26/03/25
• ² Loftin, L. K., Jr. (1985). Quest for Performance: The Evolution of Modern Aircraft (NASA-SP-468). NASA Scientific and Technical Information Branch.
• ³ Lunday, A. (2018, June 20). New “E-Dermis” Brings Sense of Touch, Pain to Prosthetic Hands. Johns Hopkins Biomedical Engineering., available at: https://www.bme.jhu.edu/news-events/news/new-e-dermis-brings-sense-of-touch-pain-to-prosthetic-hands/ accessed 25/03/25
• ⁴ Lacour, S. P. (2020, August 17). Pain-sensing electronic silicone skin paves the way for smart prosthetics and skin grafts. The Conversation. available at: https://theconversation.com/pain-sensing-electronic-silicone-skin-paves-the-way-for-smart-prosthetics-and-skin-grafts-145386 accessed 25/03/24
• ⁵ Graczyk, E. L., Resnik, L., Schiefer, M. A., & Tyler, D. J. (2023). Peripheral nerve stimulation enables somatosensory feedback while treating phantom limb pain: Long-term usability and satisfaction. Brain Stimulation, 16(5), 1302-1311. https://www.sciencedirect.com/science/article/pii/S1935861X23017618
• ⁶ Dietrich, C., Nehrdich, S., Seifert, S., Asper, R., Miltner, W. H. R., & Weiss, T. (2012). Sensory feedback prosthesis reduces phantom limb pain: Proof of a principle. Neuroscience Letters, 507(2), 97-100. https://www.sciencedirect.com/science/article/abs/pii/S0304394011014807
• ⁷ Dietrich, C., Nehrdich, S., Seifert, S., Blume, K. R., Miltner, W. H. R., Hofmann, G. O., & Weiss, T. (2018). Leg prosthesis with somatosensory feedback reduces phantom limb pain and increases functionality. Frontiers in Neurology, 9, 270. https://www.frontiersin.org/articles/10.3389/fneur.2018.00270/full
• ⁸​Marasco, P. D. (2025). Navigating the complexity of touch. Science, 387(6731), 248-249. https://www.science.org/doi/10.1126/science.adu7929​

Introduction:

While studying for a debate regarding the use of embryonic stem cells (ESCs) in research, I stumbled across articles about organoids. I remembered them being mentioned in one of our earlier lectures, therefore these articles peaked my interest. So I dug deeper. What interested me was the slightly morbid idea of growing a human brain and what that means. This digging led to another branch of this scientific, dystopian tree: brain chimeras. In this blog, I will be discussing why brain organoids and chimeras are made, what they are used for and what ethical issues rise.

Are we as scientists, justifying the use of these chimeras the same way Dr. Frankenstein justified the creation of his monster, selfishly in pursuit of greater knowledge despite the pain and suffering this may create?

What are they and how are they made?

Organoids are 3D, self-organised tissue cultures made from stem cells. They are made by using iPSCs (induced pluripotent stem cells) which are made from adult somatic cells. This is done by reprogramming these somatic cells using transcription factors to make the cell pluripotent similar to ESCs.

To grow these organoids the iPSCs are cultured to form an embryoid body (EB) which mimics the features of an early stage embryo. This is exposed to different mediums to encourage differentiation into brain cells then grown in a growth medium.

Organoids can be made with human stem cells and animal stem cells. This results in brain Chimeras which are made by engrafting human foetal tissue/iPSCs into a neonatal animal (e.g. mouse) brain.

Why are they important?

We all know someone who is battling with a neurological condition. Many of these conditions are debilitating, ruin lives and have high mortality rates. This highlights the significance of this research.

One in two of us will suffer with dementia in our lifetime. Therefore, research into neurodegenerative disease is more important than ever before.

Although these organoids and human-animal brain chimeras are relatively new there has been a tremendous volume of studies which use this technology. They can offer important insight into the progression of neurodegenerative disease leading to new treatments. However, one could argue that these ‘brains’ are still fundamentally different and less complex than a real human brain as most animals are biologically very different and display different symptoms of neurological problems.

The issue

The main debate lies with the idea that human brain organoids or human-animal brain chimeras could be capable of intelligent thought. This raises many concerns as currently organoids hold no legal or moral rights within science. Are these chimeras thinking the same as a human may think? Are they self aware? More complex than say an ordinary mouse? And why should this matter?

There are significant regulations when using hESCs for research, such as the 14 day rule, however, organoids and human-animal chimeras are not regulated the same way, it does not even require a license as long as it does not use hESCs. Why is this?

These brain organoids and chimeras have the same moral status as many animals that are used in research. Should this be the case?

There is no right answer here as you cannot possibly know what a chimera or brain organoid could be thinking.

Conclusions and Reflections

Prior to researching this topic I did not appreciate the complexity and possible future of these models, I had a similar initial reaction to using any animal model; that it is a cruel and disturbing idea. However, animal models and hESCs have contributed greatly to the world of science, without them many treatments (HIV medication, cancer medications, vaccines) would not have been developed. This shows how important in vivo research is and these organoid/chimeric models may just add to the possibilities.

Contrary to this, I was surprised to find that making an organoid does not require any sort of formal license. I believe organoids should be treated with the same moral significance as hESCs as there is a grey area regarding their consciousness.

In conclusion, organoids and chimeric models raise many ethical and thought provoking questions, however, they offer invaluable research opportunities which could help many people, although they should be treated with more moral significance similar to that of hESCs.

References:

CAPPS B. Do Chimeras Have Minds?: The Ethics of Clinical Research on a Human–Animal Brain Model. Cambridge Quarterly of Healthcare Ethics. 2017;26(4):577-591. doi:10.1017/S0963180117000093

Grenier, K., Kao, J. & Diamandis, P. Three-dimensional modeling of human neurodegeneration: brain organoids coming of age. Mol Psychiatry 25, 254–274 (2020). https://doi.org/10.1038/s41380-019-0500-7

Kwisda, K., White, L. & Hübner, D. Ethical arguments concerning human-animal chimera research: a systematic review. BMC Med Ethics 21, 24 (2020). https://doi.org/10.1186/s12910-020-00465-7

Eigenhuis KN, Somsen HB, van der Kroeg M, Smeenk H, Korporaal AL, Kushner SA, de Vrij FMS, van den Berg DLC. A simplified protocol for the generation of cortical brain organoids. Front Cell Neurosci. 2023 Apr 4;17:1114420. doi: 10.3389/fncel.2023.1114420. PMID: 37082206; PMCID: PMC10110973.

When we first looked at gene editing, I had mixed feelings. As some who studies engineering, I believe in innovation and using technology to help people. However, as some whose sibling has a disability, I thought about how the advancement of gene editing pushes the narrative that those with disabilities need ‘fixing’. Therefore, I decided to research the topic further.

First of all, what is gene editing?

Gene editing is the process of deleting, inserting or replacing genetic material within animals, plants and bacteria to alter their characteristics. It has different applications, but I’m focusing on gene therapy and using different techniques to treat diseases. The development of CRISPR-Cas9 has created a quicker, cheaper method for gene editing, leading to the current buzz around the topic.

Laws surrounding gene editing:

While it is illegal in the UK to implant a gene-edited embryo, in 2016, the HFEA approved licensing to allow gene editing of human embryos in research. Many of my classmates thought this was a good change as it could lead to more knowledge and potential cures about inheritable disorders like Cystic Fibrosis. However, is this any different from previous attempts in eugenics? The removal of genetics at an embryonic level will lead to the eradication of different, ‘undesirable’, traits from society. The practice may also lead to the relaxation of laws and the possibility of designer babies.

Gene therapy case:

While gene editing is often associated with inheritable disorders, it can be used to cure cancer. There have been successful results from a study in 2010, where a patient suffering from lymphoma underwent CAR T cell therapy. In this treatment, the patients T cells are collected and then genetically altered in the laboratory so they can recognise the cancerous cells. They are then put back inside the body to fight the cancerous cells.

Cost of gene editing:

However, gene therapies are expensive! In the US it is estimated that $20.4 billion is spent annually on gene therapies. If this money was spent on creating a more inclusive environment through education of the public and the changing of laws, this could have a far greater effect on the people already living with genetic disorders. Is it not better to create an environment where people can live well with these disorders, then create one which focuses on their removal?

Different opinions:

The NHGRI conducted surveys to investigate patient perspectives on gene editing. Many patients, especially those with Huntington’s, argued that gene editing should be used to prevent other people from inheriting the disease, despite the argument that it could isolate them from society and reinforce the belief that people with disabilities have a low quality of life.

Furthermore, Wellcome Connecting Science hosted a citizen’s jury vote based on the following question: ‘Are there any circumstances under which a UK Government should consider changing the law to allow intentional genome editing of human embryos for serious genetic conditions?’. All the jurors had been affected in one way or another by hereditary diseases and by the end most jurors (17-4) agreed that human embryos should be edited. While a small sample, this vote indicates that the scientific community and the legislators are listening to those who it truly affects, something which has previously been overlooked and distinguishes gene editing from previous, eugenic practices.

Final Thoughts

I believe that the advancement of gene editing will help those with genetic disorders and provides cures which were previously unavailable. I think that this outweighs the negatives of gene editing especially considering many people with genetic disorders believe in the benefits. However, I think that the narrative surrounding gene editing needs to include those who are affected the most to make sure that it is continuing to be done in a positive way which doesn’t isolate people or become modern-day eugenics.