Featured How it works

How it’s made: agar art

You might be familiar with agar plates from your high school science lab – petri dishes filled with agar, a jelly-like substance. Maybe you used them in an experiment to grow bacteria from samples taken around your school, like elevator buttons, door handles or even toilet seats (I remember doing this experiment in high school, and finding that the toilet seats were actually surprisingly clean!).

But, did you know that bacteria and agar plates can be used to create art, too?

In the hospital’s Microbiology laboratory, samples taken from patient specimens are grown on agar plates, producing unique colonies and colours. Those culture plates are used to determine the kind of bacteria causing a patient’s infections, helping the care team select the most appropriate treatment.

Often, those colonies and colours can end up resembling art rather than a lab test. In fact, “agar art” is its own art form: for the past three years, the American Society for Microbiology (ASM) has held an agar art competition, accepting submissions from around the world.

This year, Sunnybrook laboratory technologist Linh Ngo entered that competition after finding inspiration in the Disney film Finding Nemo. “I was amazed at the similarities between the coral reef and the bacteria I work with in the lab, and I wanted to recreate that on agar plates,” she says.

Linh made the agar art in the six steps described below:

Start planning early

Linh says she first had the idea to create agar art of a coral reef last year, but missed the deadline. In November 2016, she started coming up with a concept for her submission. She also loves to draw, so she started sketching ideas. For example, Linh found inspiration for how to draw the brain coral (at the bottom of the image) in an online photo. Once she created a drawing she was satisfied, she was ready to start sketching it onto the actual agar plates.

Keep an eye out for colourful bacteria

Now that she had an idea of how she wanted the finished product to look, Linh and several of her colleagues started keeping an eye out for organisms that produced the vibrant colours she was looking for. For example, “some strains of Serratia marcescens produce a pigment called prodigiosin, which give the colonies a dark red/purple appearance, so when I finally came across a strain with that colour, I froze it for a few months,” Linh says.

Paint with a steady hand

After finding the organisms that would produce the colours she wanted, Linh used the tip of a pipette to “paint” with the bacteria on a series of five agar plates. “I had to be careful not to have any overlap of the different bacteria because if there was, it would alter the image. There was a lot of trial and error,” she says. When the original drawing she wanted to use as a guide didn’t work, she ended up painting freehand.

Be ready to experiment…

Finding the right organisms to work with was a time-consuming process. “Every time I used four to five types of bacteria on the same agar plate, the bacteria would grow into each other, and the colours and image would be ruined. So I had to figure out how to work with just two bacteria per plate,” Linh says. The colours she ended up using were derived from Serratia marcescens (purple), Staphylococcus aureus (pink, and a little green), Candida tropicalis (white) and Klebsiella pneumonia (grey, mucoid).

…and keep experimenting!

For the next step in the process, which involved putting the agar plates in an incubator, Linh also had to experiment with the incubation times. This is because different organisms are capable of lowering the pH in the medium and can cause a change in colour, especially when multiple organisms are present on the same plate. “By the time some bacteria produced the colour I was looking for, the colour of the other bacteria would have changed. It took several tries to get the timing right,” she says.

Don’t give up

In all, Linh estimates that she made about eight revisions to her original drawing, and went through dozens of test plates before perfecting her submission. Looking back, Linh says she should have given herself more time to prepare her agar art. “I had two months to make the agar art, but a few more weeks definitely would’ve been helpful. I almost ran out of time!”

Linh named her stunning image of a coral reef “Finding pneumo” (named after the movie that inspired her and one of the bacteria she used, Klebsiella pneumonia). The result far exceeded her expectations: she won second place in the ASM competition, beating out 264 submissions from 36 countries. Congratulations, Linh!

About the author

Sybil Millar

Sybil Millar

Sybil Millar is the Communications Advisor for the Ross Tilley Burn Centre, Critical Care and Infectious Diseases programs at Sunnybrook.

Have a question about this post? Get in touch.