Icing on the cake: combining a dual PEG-functionalized pillararene and an A-D-A small molecule photosensitizer for multimodal phototherapy

The design of photosensitizers with multimodal antitumor activity and the construction of nanocarriers with specific targeting are two magic weapons to achieve highly efficient tumor phototherapy. Here we developed an A-D-A fused-ring conjugated small molecule photosensitizer DPIC and proposed a new strategy of constructing phototherapy agents, namely using supramolecular vesicles constructed by the self-assembly of a novel dual PEG-functionalized pillararene WP5-2PEG to load DPIC. These new nanocarriers had excellent water solubility and drug encapsulation rates. The prepared DPIC NPs had a better water solubility compared with DPIC molecules and had a uniform hollow spherical morphology, which is beneficial for cell endocytosis. Under laser irradiation (808 nm), the DPIC NPs had a photothermal conversion efficiency (PTCE) of 55% and a PTCE of 49% under 980-nm laser irradiation. The DPIC NPs also displayed dual type I and type II photodynamic activity. DPIC NPs had superior biocompatibility and stability and can also inhibit tumor growth in vitro and in vivo, demonstrating their potential for highly efficient cancer phototherapy.