Week 4 Cont. - Investigation of Filtration and Preventing Disease

The application of our nanofibers will be to create a filter that will block microbes and bacteria that cause disease. The conducted research in this specific area, more specifically, seeing what are the most common bacteria in contaminated water, what are the ranges of size of these bacteria, and the effects of the specific bacterium. The four most common bacteria in untreated water were Fecal Coliform (general), E. Coli, Enterococcus Faecium, and Giardia [14]. The overarching goal is to create a filter that has a specific pattern (most likely a square-crossing pattern) in order to block and trap the bacteria that are in the water supply. PEO is miscible in water that is why this experiment will a larger control in which other solutions that are immiscible in water can be spun and used.


Classification of Bacteria in Water that Cause Disease:

Figure 7. Fecal Coliform Colony (SEM magnified) [7]

Fecal Coliform, as seen to the left, are rod-shaped, small, non-sporulating bacterium. They are not very hazardous to human health; however, specific strains of them (E. Coli) can be very dangerous and potentially life-threatening. Failing home septic systems can allow coliforms in the effluent to flow into the water table, aquifers, drainage ditches and nearby surface waters. Sewage connections that are connected to storm drain pipes can also allow human sewage into surface waters [14]. Animal waste as well as agriculture waste from fertilizers contribute to the formation of coliform. Severe diseases can arise from lethal strains of this bacterium such as: ear infections, dysentery, typhoid fever, viral and bacterial gastroenteritis, and hepatitis A [14]. Without proper treatment, deadly genetic mutations of the RNA inside the bacterium will be certain death. This specific bacterium is approximately 0.60~0.70 μm in diameter and has an approximate volume of 0.816 cubic μm. The nanofibers spun must be so the diameter of each fiber is approximately 0.50 μm and the area of the square pattern is smaller than the diameter of one of these bacteria.

Figure 8. E. Coli under SEM Imaging [10]

A specific form of Fecal Coliform is E. Coli which is known to be a deadly without treatment. Virulent strains of E. coli can cause gastroenteritis, urinary tract infections, and neonatal meningitis.[14]. E. Coli is approximately 2.0 μm in length, has a diameter of 0.50 μm, and volume of 0.70 cubic μm. Although E. Coli is relatively easy to treat if found in the early stages of the disease, it can be lethal if found too late. E. Coli is especially tricky to diagnose because the symptoms arise right before serious illness so there is a insufficient amount of time to kill the bacterium.The image on the right shows how E. Coli are rod-shaped and also are always in colonies.


The last two common bacteria found in contaminated water are Enterococcus Faecium and Giardia. E. Faecium is quite large; with a length of 1 to 2 mm [14]. They can move very fast and are known to target human arteries and hearts. They usually overtake and replace Fecal Coliform in water supply by engulfing them through phagocytosis (cell membrane forming around a substance or foreign object) [14]. Giardia cysts are 8 to 14 μm and the actual bacterium is about 5 μm in diameter. Giardia has symptoms that mimic other gastrointestinal problems and the common symptoms are persistent diarrhea, weight loss, abdominal cramps, nausea, and dehydration. In general, the symptoms begin within a week after exposure and the acute symptoms can last for up to 2 weeks, but chronic symptoms can last for up to 2 months [14]. Usually it is not life-threatening but treatment must be given to get rid of both bacteria.

Figure 9. E. Faecium infecting pulmonary tissue [10]

Figure 10. Giardia in water supply [10]

Since the smallest form of Fecal Coliform is the smallest parameter of bacteria size in water supply, a filter must be created to take the size and dimensions of the bacteria into account. The filter mechanism is actually possible to create because the size and pattern shape can be created through mechanical/technological systems.