A pH‐Responsive Layered Double Hydroxide (LDH)–Phthalocyanine Nanohybrid for Efficient Photodynamic Therapy. Issue 8 (9th January 2015)

• Record Type: Journal Article
• Authors: Li, Xing‐Shu; Ke, Mei‐Rong; Huang, Wei; Ye, Chun‐Hong; Huang, Jian‐Dong
• Is Part Of: Chemistry. Volume 21:Issue 8(2015)
• Page Start: 3310
• Page End: 3317
• Publication Date: 2015-01-09
• Subjects: drug design -- layered compounds -- nanoparticles -- phthalocyanines -- zinc; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201404514
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A pH‐responsive nanohybrid (LDH–ZnPcPS4 ), in which a highly hydrophilic zinc(II) phthalocyanine tetra‐α‐substituted with 4‐sulfonatophenoxy groups (ZnPcPS4 ) is incorporated with a cationic layered double hydroxide (LDH) based on electrostatic interaction, has been specially designed and prepared through a facile co‐precipitation approach. ZnPcPS4 is an excellent singlet‐oxygen generator with strong absorption at the near‐infrared region (692 nm) in cellular culture media, whereas the photoactivities of ZnPcPS4 were remarkably inhibited after incorporation with the LDH. The nanohybrid is essentially stable in aqueous media at pH 7.4; nevertheless, in slightly acidic media of pH 6.5 or 5.0, ZnPcPS4 can be efficiently released from the LDH matrix, thus leading to restoration of the photoactivities. The nanohybrid shows a high photocytotoxicity against HepG2 cells as a result of much more efficient cellular uptake and preferential accumulation in lysosomes, whereby the acidic environment leads to the release of ZnPcPS4 . The IC50 value of LDH–ZnPcPS4 is as low as 0.053 μM, which is 24‐fold lower than that of ZnPcPS4 . This work provides a facile approach for the fabrication of photosensitizers with high photocytotoxicity, potential tumor selectivity, and rapid clearance character. Abstract : Catch and release : A deactivated nanohybrid, in which a highly hydrophilic zinc(II) phthalocyanine is incorporated with a cationic layered double hydroxide (LDH) based on electrostatic interactions, has been designed and prepared (see figure). The nanohybrid is pH‐ responsive and capable of selectively releasing the phthalocyanine from the LDH matrix in slightly acidic media, thus leading to restoration of the photoactivity for photodynamic therapy (PDT).