SEM: A Big Machine for Little Things

This week I spent more time preparing for the next chapter of my dissertation, which involves an experimental design that hinges on bacterial growth. Therefore, I have been preparing my samples for imaging using the SEM, scanning electron microscope. An SEM is a very high-powered microscope that scans a sample's surface using a beam of electrons. This scan produces an image of the topography of the materials that have been prepared, and is an extremely valuable tool when studying exceptionally small materials. However, not all laboratories or schools have access to SEMs, as they can range in cost from $75,000 to $10,000,000 depending on the type, manufacturer, size, and some imaging factors. Luckily, FSU has access to two SEMs (that I'm aware of) thanks to the National High Magnetic Field Laboratory (Mag Lab). 

The Mag Lab is a shared laboratory space between FSU and FAMU, and is host to a variety of materials laboratories, magnetic laboratories, and high powered microscopy tools. The Mag Lab also hosts visiting researches from around the globe, and--just like the laser lab I used in the first part of my research--is available for students to use in collaboration with other scientists. The SEM that I am preparing to use at the Mag Lab requires a multi-step sample preparation protocol before use. First, samples must be washed and frozen in a solution for an hour for preservation. Then, the samples are washed and centrifuged in a separate chemical solution. The washing and centrifugation step ensures that materials are readily available for imaging. Then the samples sit in the final 100% ethanol (alcohol) solution until the scientist is ready for imaging. The last steps before imaging require the scientist to create surfaces to put under the microscope that hold the samples and then to coat the samples in gold. The reason for gold coating the materials is to increase their conductivity to produce a better SEM image.

While I don't have any SEM images for this week, I do want to share a picture of the sample surfaces that look so inconspicuous but hold the future of this experiment. Here on the right are 11 test samples I am running before beginning my main experiment. When I designed this experiment, Dr. Ingels and I realized the need for some methodology testing before conducting the full experiment to save money if things go wrong. I hope that everything works out and that I can bring you some test results next week.

Stay tuned, because next week's blog should be a really exciting one based on my schedule.

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