Abstract：Objective: In order to overcome the quenching of the traditional micromolecular porphyrin drug,the targeting polymer nanoparticles with porphyrin were obtained. Methods:Porphyrin-cored star-shaped poly(caprolactone)-block-poly(ethylene glycol) copolymers (SPPCL-b-PEO) were synthesized via ringopening polymerization and esterification reaction,and were characterized by gel permeation chromatograph,nuclear magnetic resonance spectrum,fourier transform infrared spectroscopy and ultraviolet visible spectroscopy.The photosensitizing efficiency of SPPCL-b-PEO investigated by fluorescence probe method.The selfassembly behavior of SPPCL-b-PEO was investigated by transmission electron microscope.The drug loading and release properties of SPPCL-b-PEO were studied by ultraviolet visible spectroscopy. Results:The polymeric poly(caprolactone)-block-poly(ethylene glycol)(PCL-PEO) skeleton can efficiently prevent selfquenching of the central porphyrin in the copolymers.The selfassembled aggregates changed from spherical micelles to wormlike micelles with decreasing the weight fraction of hydrophilic poly(ethylene glycol)(PEO) block in the copolymers.The Doxorubicinloaded SPPCLbPEO nanospheres possess the high drug content and entrapment efficiency, and exhibit property of pH-induced drug release. Conclusion: SPPCLbPEO will not only provide potential porphyrin core for photodynamic therapy but also improve targeting to pH5～6 tumor tissues for drug delivery.
2013, Vol. 23 
