Pyropheophorbide A and c(RGDyK) comodified chitosan-wrapped upconversion nanoparticle for targeted near-infrared photodynamic therapy

Mol Pharm. 2012 Jun 4;9(6):1580-9. doi: 10.1021/mp200590y. Epub 2012 May 8.


Near-infrared (NIR)-to-visible upconversion nanoparticle (UCNP) has shown promising prospects in photodynamic therapy (PDT) as a drug carrier or energy donor. In this work, a photosensitizer pyropheophorbide a (Ppa) and RGD peptide c(RGDyK) comodified chitosan-wrapped NaYF(4):Yb/Er upconversion nanoparticle UCNP-Ppa-RGD was developed for targeted near-infrared photodynamic therapy. The properties of UCNP-Ppa-RGD, such as morphology, stability, optical spectroscopy and singlet oxygen generation efficiency, were investigated. The results show that covalently linked pyropheophorbide a molecule not only is stable but also retains its spectroscopic and functional properties. In vitro studies confirm a stronger targeting specificity of UCNP-Ppa-RGD to integrin α(v)β(3)-positive U87-MG cells compared with that in the corresponding negative group. The photosensitizer-attached nanostructure exhibited low dark toxicity and high phototoxicity against cancer cells upon 980 nm laser irradiation at an appropriate dosage. These results represent the first demonstration of a highly stable and efficient photosensitizer modified upconversion nanostructure for targeted near-infrared photodynamic therapy of cancer cells. The novel UCNP-Ppa-RGD nanoparticle may provide a powerful alternative for near-infrared photodynamic therapy with an improved tumor targeting specificity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Chitosan / chemistry*
  • Chlorophyll / analogs & derivatives*
  • Chlorophyll / chemistry
  • Humans
  • Nanoparticles / chemistry*
  • Oligopeptides / chemistry*
  • Photochemotherapy / methods*
  • Photosensitizing Agents / chemistry*
  • Photosensitizing Agents / pharmacology
  • Reactive Oxygen Species / metabolism


  • Oligopeptides
  • Photosensitizing Agents
  • Reactive Oxygen Species
  • Chlorophyll
  • pyropheophorbide a
  • arginyl-glycyl-aspartic acid
  • Chitosan