Synthesis and Characterization of PEG-co-DPA Nanoparticles and Application of Photodynamic Therapy
Date Issued
2009
Date
2009
Author(s)
Yang, Li-Yuan
Abstract
Photodynamic therapy (PDT) is an effective therapy for tumor, which involves the administration of photosensitizers followed by illumination. However, the insolubility and non-targeting are defects of photosensitizers. For targeting the acid environment at tumor site, Poly(ethylene glycol) methacrylate-co-2-(Diisopropylamino) ethyl methacrylate (PEGMA-co-DPA) copolymers were synthesized in the presence of 2,2’-Azobis-isobutyronitrile (AIBN) and then formed pH sensitive nanoparticles to encapsulate a photosensitizer, m-THPC. The characteristic of these copolymers were evaluated by 1H nuclear magnetic resonance and gel permeation chromatography. The pH effect on aggregation/deaggregation and critical aggregation concentration (CAC) of the nanoparticles was studied by using pyrene as a probe. The results showed that the critical aggregation pH (Ph*) of the polymers were from 5.8 to 6.6 and the CAC were from 0.0045 to 0.0089 wt% at pH 7.4. The m-THPC loaded nanoparticles were prepared by oil-in-water. The size and morphology of nanoparticles were observed using dynamic light scattering and transmission electron microscopy. The results indicated that the nanoparticles were sphere and the size was 132 nm. The drug encapsulation efficiency was 89%. The in vitro release profile performed that the release rate of m-THPC at pH 5.0 (58% m-THPC released within 48 hours) was faster than at pH 7.0 (10% m-THPC released within 48 hours). The in vitro PDT efficiency was tested with HT-29 cell line by MTT assay. These findings suggest that the pH sensitive nanoparticles prepared in this study are potential carriers for tumor targeting.
Subjects
Photodynamic therapy
tumor
photosensitizers
pH sensitive nanoparticles
m-THPC
Type
thesis
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