A cell-selective glutathione-responsive tris(phthalocyanine) as a smart photosensitiser for targeted photodynamic therapy. Issue 34 (10th August 2017)

• Record Type: Journal Article
• Authors: Chow, Sun Y. S.; Zhao, Shirui; Lo, Pui-Chi; Ng, Dennis K. P.
• Is Part Of: Dalton transactions. Volume 46:Issue 34(2017)
• Page Start: 11223
• Page End: 11229
• Publication Date: 2017-08-10
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c7dt02086d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The in vitro photodynamic activity of a bifunctional tris(phthalocyanine)-based photosensitiser has been examined. Abstract : A biotin-conjugated disulfide-linked tris(phthalocyanine) has been synthesised and characterised. As shown by electronic absorption and steady-state fluorescence spectroscopy methods, the compound remains non-aggregated in N, N -dimethylformamide, but is significantly aggregated in phosphate buffered saline with 1% Cremophor EL. The reduction in fluorescence intensity and singlet oxygen generation efficiency as compared with the monomeric counterpart suggests that the tris(phthalocyanine) exhibits an excellent self-quenching effect, particularly in an aqueous medium. Upon interaction with glutathione, both the fluorescence emission and singlet oxygen production can be restored as a result of the cleavage of the disulfide linkages, thereby releasing the phthalocyanine units and reducing their aggregation and self-quenching effects. With a biotin moiety, this tris(phthalocyanine) is preferentially taken up by the biotin-receptor-positive HeLa cells and activated by the intracellular glutathione, resulting in fluorescence recovery and photocytotoxicity with an IC50 value of 0.68 μM. This compound can therefore act as a dual functional photosensitiser.