Team:WLC-Milwaukee/Applied Design

PLACEHOLDER

WLC iGEM 2018 | System Design

System Design

An efficient system design is imperative when working with heavy metals and bacteria. While all the bacteria used during this project are safe lab strains, it is best to not introduce excessive amounts of waste to the environment. Even more importantly, while testing the design, high concentrations of lead in water were used. The most careful and environmentally conscious methods were used to dispose of all waste encountered during lab work.

Specifically, our project will work like a pill ingested to combat a disease. We will utilize gelatin capsules that contain our isolated, engineered E. coli. When the E. Coli containing capsule is submerged in a sample of potentially contaminated water, the capsule will dissolve, and our engineered E. Coli will be exposed to the contaminated water. Ideally, if that sample of water is contaminated with lead, our E. Coli will produce an enzyme that catalyzes a reaction in salicylic acid, creating methyl salicylate. This methyl salicylate has a wintergreen odor. To summarize, our system will be composed of a capsule that contains our engineered bacteria that, when exposed to a sample of water, will dissolve allowing our bacteria to produce an easily detectable scent when the water contains lead contamination.

Our project offers a quick, simple, and cheap way to test any sample of water for dangerous levels of lead contamination, leading to the pursuit of remedial action.

What is a capsule?

There are two primary types of capsules: soft capsules and hard capsules (11). The hard capsule is more commonly used and is made of two separate pieces. Soft capsules are made up of a singular piece (11).

Both types of capsules are made from gelatin which is an animal derived material used to make the polymer shell (1). Gelatin in capsules usually consists of 5-15% water in its “dry” state and as a result is incredibly soluble (10). Hard capsules tend to have a lower percentage makeup of water, therefore not being as efficient as their soft capsule counterparts.

Gelatin capsules are very cheap and can be obtained relatively easy from many websites online. A bag of 1,000 small capsules typically costs about $12-$20 depending on the size bought (4). The capsules come in many different sizes ranging from 12.1mm -22.2mm (4).

Sources:

  1. Bokas, T. Soft gel capsules: key considerations for drug makers https://www.epmmagazine.com/opinion/soft-gel-capsules-key-considerations-for-drug-makers/ (accessed Oct 1, 2019).
  2. CDC - Lead - National Health and Nutrition Examination Survey https://www.cdc.gov/nceh/lead/data/nhanes.htm (accessed Oct 1, 2019).
  3. Drinking Water and Lead https://dnr.wi.gov/topic/drinkingwater/lead.html (accessed Oct 1, 2019).
  4. Empty Gelatin Capsules https://capsuline.com/ (accessed Oct 1, 2019).
  5. Frostenson, S. 1.2 million children in the US have lead poisoning. We're only treating half of them. https://www.vox.com/science-and-health/2017/4/27/15424050/us-underreports-lead-poisoning-cases-map-community (accessed Oct 1, 2019).
  6. Lead poisoning https://www.mayoclinic.org/diseases-conditions/lead-poisoning/symptoms-causes/syc-20354717 (accessed Oct 1, 2019).
  7. Lead poisoning: MedlinePlus Medical Encyclopedia https://medlineplus.gov/ency/article/002473.htm (accessed Oct 1, 2019).
  8. Murrell, D. Lead Poisoning https://www.healthline.com/health/lead-poisoning#causes (accessed Oct 1, 2019).
  9. Spicuzza, M. Mayor Barrett declares Milwaukee has turned the corner on lead crisis https://www.jsonline.com/story/news/local/milwaukee/2018/11/16/tom-barrett-milwaukee-has-made-dramatic-progress-lead-crisis/2016862002/ (accessed Oct 1, 2019).
  10. What Are Soft and Hard Gelatin Capsules? https://www.lfatabletpresses.com/articles/soft-hard-gelatin-capsules (accessed Oct 1, 2019).
  11. What is a capsule? https://swallowingdifficulties.com/healthcare-professionals/prescribing-different-formulations/what-is-a-capsule/ (accessed Oct 1, 2019).
  12. Wintergreen: Uses, Side Effects, Interactions, Dosage, and Warning https://www.webmd.com/vitamins/ai/ingredientmono-783/wintergreen (accessed Oct 1, 2019).

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