Quick, Easy and Early Diagnosis
with Rare Earth Ions
University
of Copenhagen University of Copenhagen
in collaboration with chemists from Oxford
University
with Rare Earth Ions
Medicinal Chemistry
Two papers
to describe one novel method
Thomas
Just Sørensen is Associate Professor at the Department of Chemistry,
Nano-Science Centre, University
of Copenhagen Copenhagen
Proof of
concept for easy quick and cheap oxygen measurements
According
to Sørensen, the two articles constitute proof-of-concept that he is capable of
measuring oxygen concentrations in an easy, quick and cheap manner but he is
certain that development towards a useful technology will be speedy.
“We
have made the microscope work already, and we are getting pretty good at
synthesizing the rare earth containing molecules. Before the year is out, I am
almost certain that we will see the first medical doctors using our method for
measuring oxygen in cells”, says Thomas Just Sørensen.
Built-in
control function makes for more precise measurements
Previous
experiments have seen molecules which emit more light as the amount of oxygen
diminishes. These, however, were incapable of measuring the amount of oxygen in
cells, because one could not tell whether a large amount of light signal was
caused by a low oxygen concentration or a large concentration of oxygen
sensitive molecules. Sørensen’s new molecules solve this problem because they
have a built in control-function.
The
inventor who cannot see his own invention in action
The
novel oxygen sensitive molecule is built with two rare earths, so called
lanthanides. One lanthanide, europium, emits a constant red signal. The other,
terbium, emits a green signal that increases with diminishing oxygen
concentrations. Most physicians should be able to read the oxygen concentration
with the naked eye, explains Thomas Just Sørensen.
“You
simply deduct the amount of red light from the amount of green to get a precise
reading of the oxygen level. Unfortunately, I cannot see how well my system
works because I am red-green colour-blind. Lucky for me that optical
microscopes are usually kitted out to convert colour values to numerical
values”, smiles the inventor.
New method
measures previously invisible phenomena
Oxygen-meters
are already commercially available, but these are based on technologies which
are poorly suited for biological samples, useless in a microscope and quite
incapable of showing where the oxygen is located in a cell. Because Sørensen’s
molecules work by way of a simple colour shift, they give a very exact
indication of quantity as well as location of oxygen in a tissue sample or
inside a cell. Furthermore, the microscopy technology developed by Vosch and
Sørensen utilizes near infrared light which is highly compatible with
biological studies, because it penetrates deeply into tissue, explains
Sørensen.
“This
is not just a method which is somewhat better. With this method you will be
able to see things which used to be beyond measure. One example would be the
difference in oxygen concentration inside and outside a cell”, says Thomas Just
Sørensen.
Sørensen
is particularly proud that the light signals are visible in an ordinary optical
light microscope. Even though he readily admits that the microscope used for
the initial testing is normal only when considered as individual components.
“The
detector and light source was the same as on light microscopes found at any
hospital, but my colleague Tom Vosch has optimized the microscope to the point
where everything is almost beyond the possible. They said it couldn’t be done,
but it works”, says Thomas Just Sørensen.
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