Visual representation of the step-by-step process to use Phast Phage. Phage by Clea Doltz from Noun Project
With PhastPhage, we hope to create a kit that can be used for detection and quantification of E. coli in various water sources in a portable and efficient way compared to the existing E. coli detection methods. Ideally, we want our kit to be accessible not only to lab professionals but also to anyone who wants to test water quality.
Once we can test our current simulated model in lab with T7, there are many potential uses for PhastPhage in a variety of fields. The quick, expedited analysis can be utilized in industries like the military, where assessing the water quality on the spot is extremely useful. Furthermore, we also envision PhastPhage to be utilized for water testing in public areas like beaches to provide a water quality assessment for E. coli. More information can be found on the Human Practices page.
To utilize this technology, a person will first need to obtain a water sample and run it through a two-tiered system of filters. The first filter, a 5-micron filter, will remove any large particles/debris found within the water sample. The second filter, a 0.2-micron filter, will then be used to concentrate the sample by removing excess liquid while maintaining E. coli within the sample. This will create higher concentrations of the host bacteria for the phage to lyse effectively. This practice of filtering the samples prior to testing them was suggested by the TU Delft team. More information can be found on the Partnership page. Then, our prepared PhastPhage solution will be added into the water sample. To ensure the bacteriophage is able to infect our targeted bacteria and replicate, we may use a heating block or small incubator to keep a stable temperature for incubation. The idea for a portable incubator is based on a previous project implementing a remote water testing kit using a sulfate reducing bacteria as an indicator to detect fecal bacteria in water. They were able to achieve onsite incubation by transforming a small yogurt maker into an incubator. (Nair et al. 2007) We plan to incubate the solution for a couple of hours before observing the signal produced from our chosen colorimetric reporter protein. This may be a chromoprotein or potentially another fluorescent protein-like GFP, which we used in our modeling as a proof of concept. To quantify these results, a portable spectrophotometer can be used to analyze the results and quantify the absorbance. Then, using the absorbance, we hope to calculate the number of bacterial cells present by predicting how many molecules of the specific colorimetric protein is produced by the phage per bacterial cell. This data can be displayed as a calibration curve that links the amount of signal produced to the number of cells expected to be in the sample. We will continue to work on the specifics of implementing PhastPhage in lab over the next year in phase 2 of our project.
In the implementation of our project, it is important to us that our PhastPhage does not contaminate the water source we are collecting our sample from. While we do not believe PhastPhage to be a potential hazard to the environment, we did consider the possible negative impacts of this project through a dual-use workshop. More information can be found on the Safety page.
Nair, J., Mathew, K., Ho, G. (2007) ‘Experiences with implementing the H2S method for testing bacterial quality of drinking water in remote aboriginal communities in Australia’ Journal of Water and Health