A phthalocyanine-based self-assembled nanophotosensitizer for efficient in vivo photodynamic anticancer therapy.

To develop highly efficient photosensitizers for photodynamic therapy, herein a zinc(II) phthalocyanine-folate conjugate (PcN-FA) used to construct an activatable nanophotosensitizer (NanoPcN-FA) through a facile self-assembly. The self-assembled nanophotosensitizer (NanoPcN) without folate-modification was used as a negative control. After self-assembly, the photoactivities of NanoPcN-FA was quenched. The in vitro studies showed that NanoPcN-FA could be taken in by folate-receptor (FR)-positive SKOV3 cells and activated in the cells. It also exhibited slightly higher photocytotoxicity against SKOV3 cells than NanoPcN. Moreover, the competitive assay confirmed that the cellular uptake of NanoPcN-FA was through a FR-mediated process. Finally, the in vivo results indicated that NanoPcN-FA could target tumor tissue of S180 rat ascitic tumor-bearing mice due to the folic acid (FA) ligand, leading to a highly efficient antitumor photodynamic efficacy with the tumor inhibition rate of 95%.

A pH-responsive stellate mesoporous silica based nanophotosensitizer for in vivo cancer diagnosis and targeted photodynamic therapy.

Development of a photosensitizer that can achieve tumor specificity, improve therapeutic efficacy, and reduce side effects remains a challenge for photodynamic therapy (PDT). In this work, a pH-sensitive activatable nanophotosensitizer (SMSN-ZnPc1) has been elaborately designed, which could be readily prepared by using a functionalized zinc(ii) phthalocyanine (ZnPc) to conjugate with stellate mesoporous silica nanoparticles (SMSNs) through an acid-sensitive hydrazone bond. Meanwhile, a non-activatable analogue SMSN-ZnPc2 has also been prepared as a negative control. The fluorescence emission and singlet oxygen generation of the photosensitizer are essentially quenched in the intact nanophotosensitizer. However, these properties of SMSN-ZnPc1 can be restored greatly both in acidic solutions and at the cellular level. More importantly, after intravenous administration, SMSN-ZnPc1 can also be selectively activated at the tumor site and exhibit efficient tumor growth inhibition in S180 rat ascitic tumor-bearing KM mice with negligible systemic toxicity. It thus may serve as a promising nanoplatform for cancer diagnosis and targeted PDT.

[Non-covalent albumin conjugates of silicon (IV) phthalocyanines axially substituted with nucleoside: preparation and in vitro photodynamic activities].

The interactions of bovine serum albumin (BSA) with five novel silicon (N) phthalocyanines(SiPcl-5) axially modified by nucleosides (cytidine, 5-N-cytidine, methyl cytidine, uridine and methyl uridine) derivatives were studied by fluorescence spectroscopy. The results show that there are strong interactions between these silicon phthalocyanines and BSA with a binding constant of (4.90-83.18) x 10(5) mol(-1) x L. Therefore, the non-covalent BSA conjugate of bis(2', 3'-O-isopropyl-cytidine-oxy) phthalocyaninatosilicon(IV) (SiPc1) was further been prepared. The molar ratio of phthalocyanine to albumin was found to be 1:1 for the obtained SiPcl-BSA conjugate. The absorption spectra of SiPc1 and SiPc1-BSA in the visible region have no significant difference, both showing an Q-band maximum at about 686 nm. It indicates that the spectroscopic characteristics of SiPc1 are not affected by binding to albumin. The SiPcl-BSA conjugate exhibits high photodynamic activity against human hepatoma cell line HepG2 with an IC50 value of 3.0 x 10(-7) mol x L(-1). By comparsion, SiPc1-BSA has a higher photodynamic activity than SiPc1 (in PBS formation, IC50 = 7.0 x 10(-7) mol x L(-1)), which can be attributed to its higher cellular uptake.