Role of growth regulatory pathways in eye development and differentiation

Erika Lynn Wittkorn


A novel di-runthenated porphyrin has been synthesized that is capable of photocleaving plasmid DNA within the photodynamic therapy window of 600-800nm. The desired porphyrin was synthesized through reaction of 4-pyridine carboxaldehyde, 4-trifuorlomethyl benzaldehyde and pyrrole under reflux in propionic acid and isolated through column chromatography using methylene chloride/methanol as the eluent. Coordination of cis-Ru(bipy₂Cl₂ moieties was achieved through reflux under nitrogen in glacial acetic acid to give the bis-Ru(bipy)₂Cl₂ [5,15-(4-pyridyl)-10,20-(p-trifluoromethylphenyl)-porphyrin. UV-Vis spectra of the porphyrin and its ruthenated analog revealed an intense Soret band at 410 nm and Q-bands at 500 and 650nm. Cyclic voltammetry was used to determine the oxidative and reductive characteristics of the porphyrin and its ruthenated analog. DNA titrations using buffered solutions of the ruthenated porphyrin and calf thymus DNA were performed spectrophotometrically. The binding constant of the ruthenated porphyrin was determined to be 1.30 x 10⁶ M⁻¹. The ability of the ruthenated porphyrin to photocleave DNA was evaluated by irradiating aqueous samples of plasmid DNA and the complex at a ratio of 5 base pairs to 1 complex using a mercury arc lamp with a 500nm filter. Use of the 500nm filter allowed for observation of the photodynamic therapy window of 600-800nm. Samples were taken at 5 minute intervals and compared using gel electrophoresis to confirm the formation of the photocleaved nicked form of the plasmid DNA.