2008-04-25

Thanks to my university's annual sem image competition, I had the rare opportunity to use a scanning electron microscope for fun.

One of the things I was curious to see under the microscope was the protein powder I use to supplement my mostly-vegetarian diet.

In order to predictably interact with the microscope's electron beam, the sample had to first be secured with an electrically conductive adhesive and then coated in gold:

loading specimens into the vacuum chamber of a scanning electron microscope

The microscope stage slides into a vacuum chamber on a vibration dampened workbench. I'm told that at high zoom levels the image can still be distorted by people walking around the building, so sensitive work is scheduled after-hours.

loading specimens into the vacuum chamber of a scanning electron microscope

The electron beam scans quickly enough that a low resolution image can be displayed in nearโ€“real time. At the lowest zoom level, the entire stage is visible:

sample stage in a scanning electron microscope

Zooming in to an approximately 2-mm wide view, the protein powder begins to appear heterogeneous, like a field of debris:

2-mm view of protein powder in a scanning electron microscope

In the center is something that looks like a cell. It's about 100 ฮผm in diameter, and littered with the shattered pieces of something shell-like:

100-ฮผm view of protein powder in a scanning electron microscope

Returning to the 2-mm wide view, a crystal stands out:

2-mm view of protein powder in a scanning electron microscope

It's about 300 ฮผm long:

400-ฮผm view of protein powder in a scanning electron microscope

At a 100-ฮผm wide view, more of the shattered fragments are visible. For the next images I tried increasing the resolution of the scan. The results are clearer, but each image takes several minutes to capture.

100-ฮผm view of protein powder in a scanning electron microscope

Looking around more, most of the powder is comprised of these rounded, globular clumps. This 100-ฮผm long piece has been broken open to reveal air bubbles:

100-ฮผm view of protein powder in a scanning electron microscope

Time is short on the electron microscope, so that's all I was able to capture of the protein powder. I'm not sure what to make of it, but I'm quite thankful for the experience.