Supramolecular nanocarriers integrated with dendrimers encapsulating photosensitizers for effective photodynamic therapy and photochemical gene delivery

Recently, biomedical applications of dendrimers, three-dimensional tree-like macromolecules, have received much attention. In this paper, we introduce new biomedical applications of functional dendrimers: dendrimers encapsulating photosensitizers composed of a center dye molecule surrounded by poly(benzyl ether) dendrons with ionic peripheral groups as a new type of photosensitizer (PS) for photodynamic therapy (PDT). Dendrimers encapsulating porphyrin and with ionic peripheral groups (DPs) spontaneously formed polyion complex (PIC) micelles through electrostatic interactions with oppositely-charged block copolymers, and showed no self-quenching of the center dye molecule inside the micellar core due to a unique DP structure, leading to remarkable in vitro photocytotoxicity. The DP-incorporated micelles showed successful treatment of choroidal neovascularization (CNV) in rats without any sign of side effects. Thus, the DP-incorporated micelles are expected to be an innovative PS formulation for successful PDT against ophthalmic diseases. In this paper, we also review polymeric micelles incorporating phthalocyanine core dendrimers (DPc) for cancer PDT and novel light-responsive supramolecular gene carriers integrated with DPc for site-directed transfection in vivo.