A piperazine-substituted phthalocyanine with rapid cellular uptake and dual organelle-targeting for in vitro photodynamic therapy.

The rational design of photosensitizers with rapid cellular uptake and dual-organelle targeting ability is essential for enhancing the efficacy of photodynamic therapy (PDT). However, achieving this goal is a great challenge. In this paper, a novel axial piperazine substituted (PIP) silicon phthalocyanine (PIP-SiPc) has been synthesized. The PIP substitution significantly improved the cellular uptake of PIP-SiPc in MCF-7 breast cancer cells, as demonstrated by two-photon fluorescence imaging combined with fluorescence correlation spectroscopy. Additionally, PIP-SiPc was able to target both mitochondria and lysosomes simultaneously. Notably, PIP-SiPc exhibited remarkable singlet oxygen generation ability, leading to apoptosis in cancer cells upon irradiation, with an IC50 value of only 0.2 µM. These findings highlight the effectiveness of PIP-SiPc as a multifunctional photosensitizer for PDT.