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Updated: Jul 4, 2026
Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers
Published on: October 28, 2015
Contrast-enhanced MRI-guided photodynamic cancer therapy with a pegylated bifunctional polymer conjugate
Anagha Vaidya1, Yongen Sun, Yi Feng
1Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
Purpose:
To study contrast-enhanced MRI guided photodynamic therapy with a pegylated bifunctional polymer conjugate containing an MRI contrast agent and a photosensitizer for minimally invasive image-guided cancer treatment.
Methods:
Pegylated and non-pegylated poly-(L-glutamic acid) conjugates containing mesochlorin e6, a photosensitizer, and Gd(III)-DO3A, an MRI contrast agent, were synthesized. The effect of pegylation on the biodistribution and tumor targeting was non-invasively visualized in mice bearing MDA-MB-231 tumor xenografts with MRI. MRI-guided photodynamic therapy was carried out in the tumor bearing mice. Tumor response to photodynamic therapy was evaluated by dynamic contrast enhanced MRI and histological analysis.
Results:
The pegylated conjugate had longer blood circulation, lower liver uptake and higher tumor accumulation than the non-pegylated conjugate as shown by MRI. Site-directed laser irradiation of tumors resulted in higher therapeutic efficacy for the pegylated conjugate than the non-pegylated conjugate. Moreover, animals treated with photodynamic therapy showed reduced vascular permeability on DCE-MRI and decreased microvessel density in histological analysis.
Conclusions:
Pegylation of the polymer bifunctional conjugates reduced non-specific liver uptake and increased tumor uptake, resulting in significant tumor contrast enhancement and high therapeutic efficacy. The pegylated poly(L-glutamic acid) bifunctional conjugate is promising for contrast enhanced MRI guided photodynamic therapy in cancer treatment.
