Project Abstract
The “Silent Killer” Nitrous Oxide (
Notably, the largest proportion of nitrous oxide produced is from the agricultural sector which is why initially our project focussed on aiding that sphere. As we consulted with farmers and scientists specialising in
We figured out that we could specialise our project within an area that was underlooked at; we looked closer to home, to the National Health Service. The National Health Service is the publicly funded healthcare system in the UK. After speaking to Lyndsay Muirhead, Clinical Sustainability Project Manager of the University College London Hospital NHS Trust, we became aware of
Figure of total carbon footprint from: Office for National Statistics (2024). Measuring UK Greenhouse Gas Emissions - Office for National Statistics. [online] Ons.gov.uk. Available at: https://www.ons.gov.uk/economy/environmentalaccounts/methodologies/measuringukgreenhousegasemissions#:~:text=In%202023%2C%20total%20UK%20territorial [Accessed 22 Sep. 2024].Figure for percentage of total carbon footprint is from healthcare sectors and within that the NHS sector: Mehlmann-Wicks, J. (2023). More support needed to help the NHS reach net zero. [online] The British Medical Association is the trade union and professional body for doctors in the UK. Available at: https://www.bma.org.uk/what-we-do/population-health/protecting-people-from-threats-to-health/more-support-needed-to-help-the-nhs-reach-net-zero#:~:text=The%20health%20service%20contributes%20around.Figure for percentage of carbon footprint that represents nitrous oxide emissions: Evidence-Based Policy Report: Reducing Environmental Emissions attributed to Piped Nitrous Oxide Products within NHS Hospitals. (n.d.). Available at: https://www.publications.scot.nhs.uk/files/piped-nitrous-oxide-products.pdf.
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However, Entonox presents a secondary issue in hospitals: a threat to staff safety. In the USA, the 'safe' exposure limit is set at 25 parts per million (ppm) (note: Mills, G.H., Singh, D., Longan, M., O’Sullivan, J. and Caunt, J.A. (1996). Nitrous Oxide Exposure on the Labour Ward. International Journal of Obstetric Anesthesia, 5(3), pp.160–164. doi:https://doi.org/10.1016/s0959-289x(96)80024-0. [Accessed 22 Sep. 2024]. ) , whereas in the UK, this limit is significantly higher at 100 ppm ⁶. Alarmingly, 20% of NHS hospitals have reported exceeding this 100 ppm threshold. (note: Robinson, J. (2023). Hospital Staff Exposed to Levels of Nitrous Oxide That Exceed Legal Limits in a Fifth of Trusts. [online] The Pharmaceutical Journal. Available at: https://pharmaceutical-journal.com/article/news/hospital-staff-exposed-to-levels-of-nitrous-oxide-that-exceed-legal-limits-in-a-fifth-of-trusts [Accessed 22 Sep. 2024]. ) Prolonged exposure to high concentrations of Entonox can have severe consequences, including diminished cognitive function, impaired sensory-motor skills, addiction, megaloblastic anaemia, neurological damage (such as myelopathy from vitamin B12 inactivation), bowel distension, ear injuries, agranulocytosis, and reduced fertility due to insufficient room ventilation. (note: Royal College of Nursing (2023). Risks of Exposure to Entonox to Nursing and Midwifery Staff. ) Our project aims to design a system to reduce the number of affected NHS staff members by addressing these exposure risks.
Our project would hypothetically help with two large problems within the NHS as of current in a much cheaper and more sustainable way. Due to the infrastructure already in place our project is very viable as well as localised to our region and unique with no other iGEM team before tackling this problem and only one other competitor on the mainstream market. This mainstream market competitor is Medclair. Medclair is the only other current option available for the NHS. The product we would hopefully be replacing is their mobile destruction unit (MDU). They also sell a Central Destruction Unit but our design aspects make a more suitable replacement for the MDU. The current MDU requires one unit per bed and costs around £30,000. (note: Obtained through verbal discussion with Paul Owen UK&I National Sales Manager ) whereas ours would cost £160 (note: Figure taken from Hardware cost projection - cost breakdown can be found on the engineering page ) Furthermore, through collaboration with Lyndsay Muirhead she informed us that the MDU is also very loud, hot and uncomfortable for the patients due to the mechanism used by Medclair (thermal cracking). This means the MDU also uses more energy to start up and heat to high temperatures. Furthermore, design aspects as the machine being quite large and bulky as well as taking time to turn on and off make it hard to work efficiently within the workplace. We have taken these considerations on board when designing our project to bring the NHS a more sustainable, cheaper alternative to ensure they can still use this important and efficient gas but not compromise the health of their workers or the environment in the process.
Our solution
Our solution is to redesign the contents of the current MDU, with the use of NosZ, an enzyme that breaks
Additionally, we needed to find a way for our E. coli to absorb more copper in an attempt to increase the rate of enzymatic activity. This is due to the role of copper ions as an essential cofactor for NosZ. In order to do this, we engineered our E. coli to upregulate ComR which suppresses ComC expression. This increases the permeability the outer membrane of E. coli to copper ions, leading to greater periplasm concentrations.
Our hardware optimises the biological design by maximising efficiency while sustaining the bacterial population through a fermenter-like cylindrical design with multiple chambers to allow several batches of expired