Maker Challenge Bacteriophage Builder Challenge

Maker Materials & Supplies

• An assortment of building materials such as Styrofoam blocks, Styrofoam spheres, Velcro, tape, string, toothpicks, straws, and pipe cleaners; optional 3D printing pens
• At least two or three different types of materials that represent “bacteria” such as fuzzy pom-poms, Velcro squares, and paper squares. Consider making these pieces large or purchasing large poms-poms in order to ensure proper scaling when comparing bacteria to viruses.

Worksheets and Attachments

Kickoff

Bacteriophages have been studied for decades as a possible treatment for bacterial diseases. Now, scientists are trying to use them for the purpose of water treatment.

Show students slides 2-4 of the Bacteriophage Builder PowerPoint Presentation to get them thinking about viruses and pathogens.

Show students this intro video, “How scientists are using viruses to fight harmful bacteria” in order to help them understand how scientists use viruses to fight harmful bacteria (the video is also on slide 5 of the PowerPoint Presentation). Consider using the transcript below to introduce the challenge:

Imagine jumping into the perfect pool on a hot summer’s day. The water is cool, crisp and clear thanks to a filter that helps to keep it clean.

Now, imagine jumping into a non-so-perfect pool. It might be green, grimey, and gross. That gunk that lines the sides of the pool is known as a biofilm. Biofilms are layers of bacteria or algae that grow on surfaces, and they form in lots of places: pools, shower tiles, and even your teeth! Biofilms also tend to form on water filters, so if you don’t replace the filters regularly, bacteria can leak into your pool or even the water you drink!

What if we could remove this biofilm without needing to replace the filter or releasing toxic chemicals into the water? Engineers have found a seemingly unlikely hero in viruses.

Just like there are viruses that infect us and make us sick, there are some viruses that specifically infect bacteria. These viruses have specific structures on their surface that help them attach to the bacteria. When the shape of the proteins on the surface of the viruses matches with the proteins on the surface of the cell wall of the bacteria, the viruses latch on and infect the bacteria, turning them into mindless virus making factories.

Some viruses even have special abilities to kill bacteria even faster using special enzymes that they brainwash the bacteria into producing for them. The problem is that there is more than one type of bacteria in these biofilms, and viruses are usually very specific to one type of bacteria. We need a way to engineer viruses so that they can infect and kill as many different bacteria as possible. That’s when you come in!

Resources

• Consider showing students this video, Viruses, by the Amoeba Sisters on how viruses infect cells.

Maker Time

Setup

1. Provide a space for students to examine building materials. Organize building materials by type, and consider assigning each item a specific dollar value: for example, toothpicks are $0.25 each, Velcro squares $1.00 each, etc.
2. If providing students with example of bacteria looks like ahead of time, place a “testing tray” (such as a paper plate or a plastic lid) at each lab table with the “bacteria” samples. 

Define the Problem & Brainstorming

1. Show students the Bacteriophage Builder PowerPoint Presentation. Tell students that they will be taking on the role of environmental engineers.
2. Distribute copies of the Bacteriophage Builder Student Worksheet. Students will complete this worksheet as they brainstorm, create, and reflect on their bacteriophage designs.
3. Instruct students to define the problem in their own words (use Slide 6 in the presentation as a guide).
4. As a class, identify the key design criteria and constraints (use Slide 8 in the presentation as a guide).

• Possible criteria: viruses can bind to bacteria, viruses infect bacteria, viruses bind to as many types of bacteria as possible.
• Possible constraints: limited to 15 minutes to design, limited in types of materials, limited in size (viruses cannot be larger than bacteria).

5. Instruct students to brainstorm possible designs and materials with their partners.

If students need prompting during the design and planning stage ask them:

• What do viruses need to be able to do in order to infect the bacteria?
• What materials do you think will fit/stick together the best?
• How does the shape impact how it can infect the bacteria?
• If we are trying to infect lots of harmful bacteria, should the virus have only one type of attachment?

Testing and Iteration

1. Give students 15 minutes to build, test, and iterate their designs.
2. Consider the following options for testing the viruses.

• Tell the students at the beginning what type of bacteria their viruses will need to infect (pom-pom bacteria, Velcro bacteria, paper bacteria, etc.) and give each group one example of each type.
• Show students the first type of bacteria and, as students finish the first round of their designs, come up to their table and say “Sure it can infect that bacteria, but can it infect this bacteria?” Introduce them to the next type of bacteria and prompt them to adjust their design.
• Do not show them any of the bacteria until the end and use the sequential natural selection approach to see which groups’ virus survives all the way through the last bacterial environment. (This is the “multivalent” phage that scientists need!)

Communicating Solutions

1. Give each group two minutes to describe their creations to the class as well as their process for how they came to their final design. Specifics of this step are provided in the Wrap Up section.

Wrap Up

Students will present their bacteriophage creations to the class, explaining their design process & results. Their presentations will need to include:

• Brainstorming Process
• Initial Prototype
• Iteration (changes to first prototype)
• Final Design
• Results from Testing
• Ideas for the Future

Students will also ask each other open-ended questions such as:

• Why did you choose to use those materials in your design?
• What did you learn from your first prototype?
• If you could change anything about your design process, what would you change?

Reinforce biology concepts by asking:

• What is it that allows viruses to attach to cells?
• What makes one type of attachment better than others?
• What might be one reason why a certain virus might be able to make your pet dog sick, but will not be able to be passed to you to make you sick?

Tips

To test the prototypes, put them in a box with the “bacteria” shake them around. This might work with some of the bacteria, but not other samples. If this method does not work, consider a second iteration by allowing students to apply more direct force on the bacteria using their phage model. 

The way to more accurately model the randomness of mutations would be to not allow students to view the bacterial biofilms ahead of time and instead have them in an opaque box. This could also help simulate the randomness of how viruses drift through solutions; students would not be able to see what they are trying to attack.

Copyright

Contributors

Supporting Program

Acknowledgements

This curriculum was based upon work supported by the National Science Foundation under Rice University Engineering Research Center for Nanotechnology Enabled Water Treatment Systems (NEWT) RET grant no.1449500. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

This maker challenge was inspired by the research conducted in the Alvarez Lab at Rice University with the mentorship of Pingfeng Yu and the guidance of Christina Crawford.