Biophysics: Ion competition around DNA


I am Abby Bull and I am a rising junior in the physics department. This past semester, I took Biophysics, a cross-disciplinary course in the Chemistry and Physics departments, and became very interested in the research that is currently taking place in the field of biophysics. Because of this, I chose to do research with Professor Andresen this summer on DNA in solution with different concentrations of ions.DNA with ions

DNA has many odd and interesting quirks about it. One of which is that it aggregates (clumps together) when +3 ions are present in solution. This is especially interesting because DNA aggregates in this case with very small concentrations of +3 ions but this phenomenon will not occur with any amount of +1 or +2 ions alone. We have DNA samples, made by Professor Andresen’s collaborators at George Washington University, with different concentrations of +1 (sodium) ions in it along with cobalthexammine  as the +3 ion in solution. I am conducting my experiments using the Induced-Coupled Plasma Optical Emission Spectrometer (ICP for short). Using the different wavelengths of light of various elements as a base, the ICP outputs the concentrations of different elements in solution. We hope to discover more about the physics behind DNA aggregation caused by the +3 ions and determine the relative concentrations of ions around DNA when it is aggregated.

In addition to my project with DNA, Steve Kenyon is working in the lab on the engineering side of experiments. He is constructing magnetic tweezers from the ground up. Magnetic tweezers are a biophysical technique that measures the forces keeping biological macromolecules together by pulling them apart using magnets.

If you want to know more about either of our projects for the summer, our lab has a group blog of our own at:


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s