Dataset of scanning electron microscopy images of freeze-dried Escherichia coli DH5α cells

This dataset comprises scanning
electron microscopy (SEM) images of freeze-dried Escherichia coli DH5α cells. Sample preparation
steps prior to imaging include a 100x dilution (with deionized water) of 15 hours
old E. coli DH5α
cells cultivated in LB Lennox medium at 37 oC and 230 rpm. Subsequently,
20 μL of the diluted culture broth was added to the carbon tape on the
copper stub, and the sample was freeze dried for 24 hours. The sample was
coated with platinum to reduce charging effects prior to SEM analysis. Most of the
SEM images in this dataset were of low magnification at 15 kV accelerating
voltage, and showed flakes of freeze-dried cells together with bright odd-shaped
crystalline deposits. Increase in magnification revealed more in-depth
morphology of the freeze-dried cells, but poor imaging conditions precluded the
identification of clusters of freeze-dried E. coli cells. Finally, a single
blurred image at 8000x magnification at 15 kV accelerating voltage revealed, in
rough contours, the outline of freeze-dried E. coli cells in close-packed
formation. Cells were of 1 μm
length and had an intact rod-shape characteristic of E. coli DH5α. Overall, the result suggested
that freeze-drying did not result in cell lysis or alter the morphology of E.
coli DH5α.