The University of Southampton

Author: Jessica Mihaylova

The lab-grown brain: engineering neural tissue

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Neurodegenerative disease has interested me for a while. Having had family with dementia and multiple sclerosis, I’ve known about them from a young age. After Nick Evan’s tissue engineering lecture, I thought about using tissue engineering to treat neurodegenerative diseases. Could we use biomaterials, 3D printing, or stem cells to regenerate lost or damaged neurones?

What are the possibilities?

Use of hydrogel for neural tissue engineering(5)

I began to look into how tissue engineering could be useful in treatment of these diseases, and found many approaches. For example, 3D printing bio-scaffolds- structures that allow cell growth and mimic the extracellular matrix. Essentially, a 3D structure which allows neurones to grow in the brain. The scaffold needs to be able to maintain integrity during implantation, not be toxic, allow neuronal migration and proliferation, allow electrochemical communication, and release substances in a controlled manner. One class of materials that looks promising is smart hydrogels. Due to their high water content, they mimic the soft tissue environment and respond to external stimuli. The scaffolds can release growth factors and provide stem cells for nerve regeneration. However, research is still in early stages, as so far, only collagen has been useful for nerve regeneration and hasn’t been implanted in patients. If research advanced, patients with neurodegenerative diseases could have this scaffold implanted to regenerate lost neurones (1).

One unique issue is that the adult brain is designed against neuronal regeneration. Neurones don’t regenerate once they’re lost and there are cell-secreted molecules which make sure of this. Any attempts to regrow neuronal tissue will face this problem and will need to avoid attack from microglia, the brain’s immune cells (2). If you want to introduce foreign material to a brain, you need a strategic and delicate approach.

Mini-brains to use as models?

Mini-brain (6)

Another interesting idea I found is that we could create mini-brains from stem cells and engineer them into neurones. This organoid could be used to model diseases like Alzheimer’s and test different treatments on it (3). Alzheimer’s disease is characterised by the build-up of amyloid plaques and tau in the brain (4). With mini-brains, mechanisms can be studied, and drugs can be tested to see if they reduce amyloid and tau build-up. Mini-brains could not only help us understand the disease, but could also be revolutionary for personalised medicine. If we use stem cells from individual patients, a personalised mini-brain could be created, allowing better treatment. This is such an exciting and innovative approach which highlights the possibilities of neural tissue engineering, and if successful in Alzheimer’s treatment, it can be used for other diseases.

What about the ethics?

It is also important to consider ethics in this research. If we get closer to engineering a lab-grown brain, could it have consciousness and feel pain and emotion? Also, current research aims to treat disease and injury, but could it be used to enhance cognitive abilities? Research is still far from these realities, but considering and putting measures in place ahead of time might not be in vain. My research into this topic exposed me to interesting ideas and I will follow the research to keep updated on how neural tissue engineering advances, and how ethics plays into the research being done.

Sources

  1. https://pmc.ncbi.nlm.nih.gov/articles/PMC10302050/
  2. https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0505
  3. https://www.thenila.com/blog/innovative-mini-brains-could-revolutionize-alzheimers-treatment
  4. https://www.alzheimers.org.uk/about-dementia/types-dementia/alzheimers-disease
  5. https://jbiomedsci.biomedcentral.com/articles/10.1186/s12929-018-0491-8
  6. https://health.economictimes.indiatimes.com/news/industry/washington-3d-mini-brains-developed-in-lab/50995518

Prosthetics with a mind of their own? An overview of BMIs in prostheses

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What is Brain-machine interface and how does it work?

In recent years, the field of neuroprosthetics has advanced greatly. Neuroprosthetic devices use Brain-Machine Interface (BMI), devices which translate signals from the brain to prosthetic limbs. These devices allow an amputee or a patient who has suffered a spinal cord injury to have prosthetic limbs which closely mimic the action of a natural limb. (1)

When a patient has a missing limb, the brain still thinks that the limb is there, and still transmits signals to the missing limb. A BMI picks up these signals using sensors, either electrodes on the scalp or brain implants. Some BMIs are more advanced and can send back signals to the brain, allowing prosthetic users to feel touch, pressure, texture and even pain. The Utah array is one example of this, an implant which allows the feeling of different textures and pressures. (2) The Modular Limb Prosthesis (MLP) is another example. In 2018, Johnny Matheny was able to play the piano with his MLP, and users have said it almost feels like a real hand. (3).

There are a lot of requirements for an implanted BMI to work, such as dealing with the hostile environment of the body. It’s unsurprising that an electrical device implanted into the most complex system known to man could cause an uproar from the brain’s immune system. Implants can cause inflammation which weakens signals and decrease the accuracy of the signal. Those in the field are still exploring materials which the brain would welcome i.e. increase the biocompatibility of BMIs (4).

Do we risk losing what makes us human? The ethical side 

Aside from the bioethics involved in many areas of medicine, such as the balance of risk and benefit, user safety, and unknown effects, the area of brain-machine interface raises a whole new set of ethical considerations. (5)

A big one is the issue of humanity and personhood. The interaction between brain and machine raises the question of whether the machine is part of the person, or simply a tool. Could the person be considered a cyborg? Does it change their sense of identity? There are also considerations of whether the device actually changes the way users think and how it affects neural pathways. Going down this route, we eventually reach the question of what is it that really makes us human, and does a little device change that? (6)

You could say that something like a missing limb changes the patient’s identity anyway, and that because of the improvement it brings to a patient’s life, using BMIs is worth it. You could also say that many medical interventions already link us with technology, such as pacemakers, so BMI doesn’t make us any more a ‘cyborg’ than any other medical device. However, BMI advancements do mean that nervous signals can be processed by artificial intelligence before reaching the prosthetic limbs, which raises questions of privacy. Does it open the possibility of thoughts being transferred to computers? It might sound far-fetched, but without appropriate regulation, the use of BMIs could lead to an almost dystopian man-machine hybrid. The field of neuroprosthetics has great potential for improving the lives of many people, and it is an exciting task which combines neuroscience and cutting-edge engineering. However, should BMI be treated with caution? Does it have the potential to alter our humanity? (7).

Sources:

(1) https://pmc.ncbi.nlm.nih.gov/articles/PMC3497935/#sec2

(2) https://www.wired.com/story/this-man-set-the-record-for-wearing-a-brain-computer-interface/

(3) https://www.jhuapl.edu/news/news-releases/210318-home-study-Modular-Prosthetic-Limb-Matheny-piano-Amazing-Grace

(4)https://www.sciencedirect.com/science/article/pii/S2452199X24003724#:~:text=Some%20materials%20trigger%20tissue%20reactions,response%20is%20minimal%20%5B42%5D.

(5)https://pmc.ncbi.nlm.nih.gov/articles/PMC7654969/#:~:text=Implanting%20the%20BCI%20sensor%20into,are%20referred%20to%20as%20the

(6) https://bmcmedethics.biomedcentral.com/articles/10.1186/s12910-017-0220-y

(7) https://pmc.ncbi.nlm.nih.gov/articles/PMC11091939/