Using the flash-quench technique to probe DNA charge transport in assemblies containing a tethered ruthenium intercalator, the kinetics and yield of methylindole radical formation as a function of DNA sequence were studied by laser spectroscopy and biochemical methods. In these assemblies, the methylindole moiety serves as an artificial base of low oxidation potential. Hole injection and subseq...

Scanning electrochemical microscopy (SECM) experiments were undertaken to study the EC’mechanism, e.g. where a product of the electrode reaction reacts to regenerate the starting material. Digital simulations of the two dimensional SECM were carried out and the results tested with the known EC’ system of Fe(CN)6 / cysteine for validation. The results were then used in SECM experiments with Ru(p...

DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM) and spectroscopy (AFS). The results have been compared with t...

A nonlabeling voltammetric detection method for DNA hybridization has been developed, in which [Fe(CN)(6)](3-) in solution can readily approach an electrode surface covered with a charge-compensated DNA duplex layer and thus provides a strong redox-sensing current. Charge compensation for negative charges on the DNA backbone has been specifically accomplished on DNA duplexes by discouraging non...

HL-60/AMSA is a human leukemia cell line that is SOto 100-fold more resistant to the cytotoxic actions of the topoisomerase II-reactive intercalator amsacrine than is its drug-sensitive 111-hi) parent line. Previously, we have shown that the topoisomerase II from HL-60/AMSA is also resistant to inhibition by amsacrine and other intercalating agents. We therefore sought the molecular basis for t...