Science Buddies: "Ask an Expert"

Hi!

I'm doing a project based on the "Tiny Titans: Can Silver Nanoparticles Neutralize E. coli Bacteria?" experiment on the website. I'm trying to study the behavior of bacteria that can become resistant to silver nanoparticles.

First, I'm going to streak half of a petri-dish with e.coli bacteria and coat the other half with varying concentrations of colloidal silver (Each petri dish would have a different concentration). Then, I'm going to observe if, over time, the bacteria becomes resistant to the colloidal silver and starts to grow on the other half of the petri dish. (I'm basing my experiment loosely of an existing study: https://news.harvard.edu/gazette/story/ ... th%20rates.")

However, I'm not sure about the feasibility of my project. First of all, I worry that the bacteria won't be able to develop resistance to the silver nanoparticles.

Likewise, in the procedure for the "Tiny Titans: Can Silver Nanoparticles Neutralize E. coli Bacteria?" experiment, it mentions that one should keep a lit candle next to the bacteria cultures to ensure the area is sterile. Since I am doing this project at home, I was wondering if it would work if I didn't constantly have a lit candle next to the experiment.

Any advice would be greatly appreciated.

Thank you,
Arushi

Hi Arushi,

This sounds like a fun project! The bacteria might not develop resistance to silver nanoparticles and that's okay! We do experiments because we don't know the answer to a question - sometimes it's yes and sometimes it's no. Your results are still meaningful either way showing that it is NOT easy for bacteria develop resistance.

I don't have much experience in this area but I know scientists sometime use UV light to promote more mutations in the bacteria's DNA and therefore increase the likelihood that a mutation that provides the desired resistance occurs. You may consider doing some research on this topic and decide if you'd like to include exposure to UV light as part of your experiment.

Regarding the suggested candle to help maintain sterility this is important while you have the lids off your petri dishes and are preparing your samples. The candle is not required after you've put the lids back on the petri dishes.

Good luck,

Audrey