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Updated: Dec 7, 2025
Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers
Published on: October 28, 2015
Photodynamic therapy using LCST polymers exerting pH-responsive isothermal phase transition
Sjaikhurrizal El Muttaqien1, Takahiro Nomoto2, Xuebo Dou3
1Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsutacho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan; Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsutacho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan; Center for Pharmaceutical and Medical Technology, Agency for the Assessment and Application of Technology (BPPT), LAPTIAB I, PUSPITEK, Serpong, Banten 15314, Indonesia.
This study introduces a novel photosensitizer-polymer conjugate that changes from hydrophilic to hydrophobic at tumor pH. This smart delivery system enhances cancer cell uptake and photodynamic therapy (PDT) efficacy while minimizing side effects.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Photodynamic Therapy
Background:
- Photosensitizer (PS) properties influence photodynamic therapy (PDT) outcomes and side effects.
- Developing targeted delivery systems for PS is crucial for improving therapeutic efficacy and reducing toxicity.
Purpose of the Study:
- To develop a pH-responsive photosensitizer-polymer conjugate for enhanced tumor targeting in PDT.
- To investigate the isothermal phase transition behavior of the conjugate in response to acidic tumor microenvironments.
Main Methods:
- Synthesized a polymer backbone poly(N-isopropylacrylamide/2-aminoisoprpylacrylamide) (P(NIPAAm/AIPAAm)) with a lower critical solution temperature (LCST) of 30°C.
- Modified the polymer with acid-labile 2-propionic-3-methylmaleic (PMM) amides to create P(NIPAAm/AIPAAm-PMM), increasing LCST to 40°C and conferring hydrophilic properties.
- Evaluated the pH-responsive phase transition, cellular uptake, phototoxicity in vitro, and tumor accumulation and PDT efficacy in vivo in subcutaneous tumor models.
Main Results:
- The P(NIPAAm/AIPAAm-PMM) conjugate exhibited a hydrophilic nature at physiological pH, minimizing non-specific interactions and photosensitivity.
- Detachment of PMM at tumorous acidic pH lowered the LCST to 30°C, enabling a hydrophilic-to-hydrophobic transition at physiological temperature (37°C).
- This pH-responsive transition significantly enhanced cancer cell uptake (8.1-fold) and phototoxicity, leading to augmented PDT effects in tumor models with reduced skin toxicity.
Conclusions:
- The developed PS-polymer conjugate utilizes pH-responsive isothermal phase transition for targeted delivery and enhanced PDT.
- This novel system demonstrates efficient tumor accumulation and therapeutic efficacy, offering a promising strategy for cancer treatment with improved safety profiles.
