Novel phthalocyanine and PEG-methacrylates based temperature-responsive polymers for targeted photodynamic therapy

A novel multi-targeting nanocarrier (SiPc-polymer) for photodynamic therapy (PDT) has been successfully polymerized via the incorporation of silicon(iv) phthalocyanine dichloride (SiPcCl₂) to the thermoresponsive PEG-methacrylates based polymers. The resulting SiPc-polymer was characterized by ¹H NMR spectroscopy, GPC, UV-Vis and elemental analysis. The lower critical solution temperature (LCST) of the SiPc-polymer can be easily controlled via changing the ratio of the applied monomers, di(ethylene glycol) methyl ether methacrylate (DEGMEMA), oligo(ethylene glycol) methyl ether methacrylate (OEGMEMA, M_w = 475 g mol^-1) and 2-hydroxyethyl methacrylate (HEMA). The synthesized polymers assemble into nanoparticles (70 nm) in aqueous solution, which normally exhibits permeation and retention (EPR) effects, the thermo-responsive features provide the possibility to selectively accumulate at a maligned tissue site upon mild heating and high singlet oxygen quantum yields (Φ_Δ = 0.55) are obtained which guarantee the controlled liberation of reactive oxygen species upon light irradiation. This provides a simple way to synthesize a multi-targeting drug carrier system for PDT. © 2013 The Royal Society of Chemistry.