July 19, 2011 Biomolecular imaging can reveal a great deal of
information about the inner workings of cells and one of the
most attractive targets for imaging are glycans -- sugars that
are ubiquitous to living organisms and abundant on cell
surfaces. Imaging a glycan requires that it be tagged or
labeled. One of the best techniques for doing this is a
technique called click chemistry. The original version of click
chemistry could only be used on cells in vitro, not in living
organisms, because the technique involved catalysis with copper,
which is toxic at high micromolar concentrations. A copper-free
version of click chemistry that can safely be used in living
organisms is available, but it is not always optimal in terms of
reaction kinetics and target specificity. Now, a variation of
click chemistry has been introduced that retains the copper
catalyst of the original reaction -- along with its speed and
specificity -- but is safe for cells in vivo. Researchers with
the Lawrence Berkeley National Laboratory