Stephanie Yang

Mentor: Dr. Sharon Burgmayer

Abstract: Photocleavage Ability Evaluation, In Vitro Toxicity Studies, and Crystallization Attempts of Ruthenium Polypyridyl Complexes

In past research, it has been shown that ruthenium polypyridyl complexes have a variety of interesting properties, most notably, the ability to intercalate with and photocleave double-stranded DNA.  This intercalation could inhibit the activity of DNA replication enzymes, prohibiting cells from duplicating and inducing cell death.   Because of this, these complexes have the capacity to be used as antitumor drugs. 

Previous researchers from the Burgmayer group have synthesized a number of Ruthenium(II) bipyridine (bpy) and phenanthroline (phen) compounds.  Using viscosity experiments, the degree of intercalation of a compound was measured and gel electrophoresis was used to evaluate the extent of a compound’s photocleavage on plasmid DNA.  However, although the phen compounds have been shown to intercalate fairly well using viscosity experiments, experiments to evaluate their effectiveness as photocleavers have yet to be conducted.   In addition to simple photocleavage studies, pH experiments were begun by Alexandra Kirsch to evaluate the pH dependency of photocleavage.  Since cancerous cells tend to have acidic pHs, these experiments hold implications for these complexes’ potential to be used as therapeutic agents.

This summer research will have three main directions.  Firstly, photocleavage studies to characterize the phen complexes will be performed.  Secondly, the pH experiments will be completed, and time permitting, in vitro toxicity experiments using cell lines will be used to test the validity of the complexes as cytotoxic drugs.  Thirdly, we hope to grow crystals of the complexes intercalating with double-stranded DNA in order to obtain a crystal structure.