Two-photon induced luminescence, singlet oxygen generation, cellular uptake and photocytotoxic properties of amphiphilic Ru(II) polypyridyl-porphyrin conjugates as potential bifunctional photodynamic therapeutic agents

Org Biomol Chem. 2011 Sep 7;9(17):6004-10. doi: 10.1039/c1ob05415e. Epub 2011 Jul 12.

Abstract

Two Ru(II) polypyridyl-porphyrin and Zn(II) porphyrin conjugates (Ru-L and Ru-Zn-L) have been synthesized and their photophysical properties studied. The two conjugates, which contained a hydrophobic tetraphenylporphyrin L conjugated via an acetylide linker at its β-position with a hydrophilic Ru(II) polypyridyl complex, showed high singlet oxygen quantum yields (>70%) and substantial two-photon absorption cross-sections (~500 GM). Ru-L gave strong emissions at ~660 and ~733 nm through linear or two-photon excitation. Solvatochromism was observed in the fluorescence spectra of Ru-L and Ru-Zn-L, where in less polar solvents (i.e., toluene and dichloromethane) their fluorescence emissions became slightly blue-shifted with a 3-fold reduction in intensity relative to those observed in polar solvents (i.e., acetonitrile and methanol). Cell-based studies of these complex conjugates were conducted using human nasopharyngeal carcinoma HK-1 and cervical carcinoma HeLa cells on which Ru-L showed rapid cellular uptake, low dark-cytotoxicity, and high photo-cytotoxicity. Furthermore, Ru-L can be excited and emits in the "biological window"in vitro, making it a potential potent new generation photodynamic therapeutic agent capable of singlet oxygen generation and in vitro near-infrared emission.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology
  • Cell Line, Tumor
  • Cytotoxins / chemistry
  • Cytotoxins / pharmacokinetics
  • Cytotoxins / pharmacology
  • Humans
  • Luminescence
  • Metalloporphyrins / chemistry*
  • Metalloporphyrins / pharmacokinetics
  • Metalloporphyrins / pharmacology*
  • Neoplasms / drug therapy
  • Photochemotherapy
  • Photosensitizing Agents / chemistry*
  • Photosensitizing Agents / pharmacokinetics
  • Photosensitizing Agents / pharmacology*
  • Singlet Oxygen / metabolism*

Substances

  • Antineoplastic Agents
  • Cytotoxins
  • Metalloporphyrins
  • Photosensitizing Agents
  • Ru(II) polypyridyl-porphyrin
  • Ru-Zn-polypyridyl-porphyrin
  • Singlet Oxygen