Photobiological Impact of [{(bpy)2Ru(dpp)}2RhCl2]Cl5 and [{(bpy)2Os(dpp)}2RhCl2]Cl5 [bpy = 2,2‘-Bipyridine; dpp = 2,3-Bis(2-pyridyl)pyrazine] on Vero Cells

The in vitro photobiology of the supramolecular complexes [{(bpy)2Ru(dpp)}2RhCl2]Cl5 and [{(bpy)2Os(dpp)}2RhCl2]Cl5 [bpy = 2,2‘-bipyridine; dpp = 2,3-bis(2-pyridyl)pyrazine] with African green monkey kidney epithelial (Vero) cells was investigated. Previously, the complexes have been shown to photocleave DNA in the presence or absence of O2. Vero cell replication was uninhibited for cells exposed to the metal complex but protected from light. Vero cells that were exposed to metal complex, rinsed, and illuminated with >460 nm light showed a replication response that was metal complex concentration-dependent. Vero cells exposed to 3.0−120 μM [{(bpy)2Ru(dpp)}2RhCl2]Cl5 and illuminated showed inhibition of cell growth, with evidence of cell death seen for complex concentrations ≥10 μM. Cells exposed to [{(bpy)2Os(dpp)}2RhCl2]Cl5 at concentrations of 5.5−110 μM, rinsed, and illuminated showed only inhibition of cell growth. The impact of [{(bpy)2Ru(dpp)}2RhCl2]Cl5 and [{(bpy)2Os(dpp)}2RhCl2]Cl5 on cell growth following illumination shows the promise of this new structural motif as a photodynamic therapy agent.