To get a super-detailed X-ray view inside a cell-right down to the
individual molecules-scientists dunk the cell they're looking at in
preservative chemicals. That not only kills the cell, it changes its internal
structure ever so slightly, meaning researchers aren't getting an exact look at
the cell's natural state. Now, scientists at Germany's DESY Research
Center have found a way around that, with a technique that's produced the
world's first X-ray of an individual living cell.
In a paper published this week in Physical
Review Letters, the team describes a system for keeping cancer cells from
the adrenal cortex alive during X-ray study. They grew the cells on silicon
nitrite plates, which are nearly invisible to X-rays, pumping nutrients to the
cells and evacuating metabolic waste through incredibly tiny 0.5 millimeter
channels.
Because long exposure to high-energy X-ray can damage or kill a living
cell, the researchers used tiny, 0.05-second X-ray blasts to produce images so
clear, even nanometer-scale structures are visible. When compared with images
of chemically-fixed cells, these X-rays prove that the chemical fixation
process makes significant changes to the tiny, 30- to 50-nanometer structures
within the cell.
Yes, technically speaking, the X-ray you got at your last dentist's
appointment was looking at (and through) living cells. But the high-energy,
super-fine X-rays needed to view nanometer-size structures have never produced
images of living cells before. A technique like this could revolutionize our
view of the structures inside cells. In fact, by proving that standard fixation
techniques change the cellular structure, it already has.
No comments:
Post a Comment