Phthalocyanine-based coordination polymer nanoparticles for enhanced photodynamic therapy.

Area of Science:

• Nanomedicine
• Photochemistry
• Cancer Therapy

Background:

• Zinc phthalocyanine (ZnPc) is a photosensitizer with potential in photodynamic therapy (PDT) for cancer.
• ZnPc's clinical application is hindered by aggregation, poor solubility, and low selectivity.
• Developing effective delivery systems is crucial for enhancing ZnPc-based PDT efficacy.

Purpose of the Study:

• To develop charge-reversal phthalocyanine-based coordination polymer nanoparticles (PCPN) to improve the therapeutic effect of ZnPc in PDT.
• To address the limitations of ZnPc, including aggregation and poor solubility.
• To enhance tumor targeting and intracellular singlet oxygen generation.

Main Methods:

• Coordination of Tetra(4-carboxyphenoxy)-phthalocyaninatozinc(ii) (TPZnPc) with zinc ions to form the PCPN core.
• Coating the PCPN core with a lipid bilayer via self-assembly (PCPNs@Lip).
• Functionalization of the nanoparticle surface with 1,2-dicarboxylic-cyclohexane anhydride modified lysyl-cholesterol (DLC) for charge-reversal properties (PCPNs@Lip/DLC).

Main Results:

• PCPNs@Lip/DLC nanoparticles maintain TPZnPc in a monomeric state, efficiently generating singlet oxygen (¹O₂).
• The charge-reversal ability of PCPNs@Lip/DLC is triggered by the acidic tumor microenvironment, enhancing cellular uptake.
• In vitro and in vivo studies demonstrated significantly improved PDT effects with PCPNs@Lip/DLC.

Conclusions:

• PCPNs@Lip/DLC nanoparticles effectively overcome the limitations of ZnPc, improving its solubility and aggregation issues.
• The charge-reversal nanoplatform enhances tumor cellular uptake and intracellular ¹O₂ generation.
• PCPNs@Lip/DLC represents a promising nanoplatform for advancing ZnPc-based photodynamic cancer therapy.