Wednesday, July 13, 2011

There's more than one way to dissect out a microbe.

Micromanipulation is just one way to isolate a single microbe.
This past week, I learned about two other methods used for single cell genomics.

The first was laser microdissection.

Laser microdissection is exactly what it sounds like.  You use a laser to cut out the cell you want.

The part you cut out literally falls down onto a collection plate.  This might sound hard but it's not.  The laser is extremely precise and very easy to control using its computer software.  What the microscope sees is shown on the computer screen.

Find your cell of interest.

Then you just use your mouse to draw around what you want to cut out, tell the laser to go, and it's done!

Draw a circle around it.

Tell the laser to cut it out.

The collection plate with the part cut out.

While it took me about 15 minutes to micromanipulate a single cell, it took me only a few minutes with the laser dissector. 

The second technique for single cell genomics I learned about was cell sorting.

The cell sorter is a device that forces cells to move one at a time past a laser beam.  The device then records how long the cell took move past the laser and how the light from laser was refracted by the cell.  These pieces of information can be related back to the size, shape, and quality of the cell.  Most of the time, the cells being sorted have been made to fluoresce.  So the device will also measure the fluorescence coming off of the cells themselves.  Together, a fingerprint for each cell type is created.  So from a mixed population of cells, the device can type each cell and sort them apart.

Before sorting

After sorting

Cell sorting is an extremely powerful yet difficult method.  My lab was able to sort 200,000 cells in a matter of minutes.  However, it took us 8 hours to set up the device to read and sort the cells the way we wanted.  Additionally, we must do further checks to confirm the cells were correctly sorted.

The ocean, mountains, and a castle!

Pacific Ocean on the left, Mt. Fuji straight ahead

Odawara Castle

Odawara Castle

Odawara Castle

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