Hello everyone!
My name is Sara Barker, and I’m a rising senior at Rice University. I’m studying Mechanical Engineering with a minor in Global Health Technologies. This summer, I’m participating in Rice 360’s internship program, where I will be working on developing a device to assist in testing for E. coli in water sources in low resource settings. I’ll be taking this project on along with my teammates on Team Petri-FI. If you’re curious about the name, think Petri as in Petri dish, or in our case, Petrifilm, and FI as in Field Incubator (more on what those terms mean later). Unfortunately, I cannot take credit for such an inventive name. We’re super excited to get a start on this project!
As our team name suggests, our task is to develop a field incubator to incubate Petrifilms for 48 hours. What exactly is a field incubator? To explain an incubator, think about how chicken eggs are hatched.
An example of an egg incubator. Source: https://diyprojects.com/homemade-incubator/
They have to be kept warm while the chicks grow inside the egg. We want to do the exact same thing, but with colonies of bacteria. Researchers who are studying water quality have to go out into the field and collect samples for testing, but any bacteria in the water are too small to see without a high-powered microscope – not something you want to lug around rural Africa or South America. Our solution is to use Petrifilms.
Petrifilm. Source: http://cels.uri.edu/docslink/ww/BacteriaWorkshop/EColi3MPetrifilm.pdf
They act just like Petri dishes – you drop some water on the pink circle, and any bacteria in that water will form colonies that will grow to be large enough to be visible to the naked eye in about 48 hours. Here’s what E. coli colonies look like on a Petrifilm:
E. coli on a petrifilm. The blue dots are E. coli colonies. Source: http://cels.uri.edu/docslink/ww/BacteriaWorkshop/EColi3MPetrifilm.pdf
Our task is to develop a device that can keep these Petrifilms at around 35-37°C continuously for 48 hours. It needs to be portable, run on a single charge, and maintain the set temperature. We’ll also be looking at implementing some advanced “smart” features, such as displaying a graph of temperature fluctuations over time on an LED screen.
However, before we can start implementing all these features, we have to do some research. This past week was spent mostly doing just that. We’ve found out a lot about E. coli – did you know fish pond water won’t have E. coli because E. coli only lives in the digestive tracts of warm-blooded animals? We’ve also been examining some past prototypes of the same project. They have different physical designs, and their respective codes are somewhat different, so we’ll have to find the best features of each design and combine them into one product.
This week, we’re going to continue to examine previous prototypes, and we’ll also outline our design criteria in preparation for building our own device. Team Petri-FI is ready to dive into this project, and I hope this blog’s readers are as excited as we are to make some progress.
See you soon in the next blog,
Sara