A fullerene-rhodamine B photosensitizer with pH-activated visible-light absorbance/fluorescence/photodynamic therapy. Issue 18 (18th April 2018)

• Record Type: Journal Article
• Authors: Tang, Qianyun; Xiao, Wanyue; Li, Jiewei; Chen, Dapeng; Zhang, Yewei; Shao, Jinjun; Dong, Xiaochen
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 18(2018)
• Page Start: 2778
• Page End: 2784
• Publication Date: 2018-04-18
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Biomedical materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8tb00372f
• Languages: English
• ISSNs: 2050-750X

Abstract

Abstract : A heavy-atom-free photosensitizer (C60 -RB) with pH-activable visible-light absorbance enhancement, fluorescence turn-on and triplet excited state generation was designed for tumor bioimaging and photodynamic therapy. Abstract : The development of smart photosensitizers with tumor microenvironment-activable fluorescence turn-on and singlet oxygen generation plays an important role in tumor bioimaging and photodynamic therapy. Herein, a pH-activable heavy-atom-free photosensitizer (C60 -RB) has been successfully synthesized through introducing a fullerene unit onto rhodamine B hydrazide. Under acidic conditions, C60 -RB, having a spirolactam structure, can be activated to its ring-opened structure C60 -RB-H and thus, visible-light absorbance enhancement, fluorescence turn-on and triplet excited state generation can be accomplished. In the presence of hydrion, the fullerene unit in C60 -RB C60 -RB-H acting as an intramolecular spin converter can cause good intersystem crossing, and the energy gap between S1 and T1 (Δ E ST ) is lowered to 0.017 eV. Through encapsulation with amphiphilic DSPE-mPEG2000, water-soluble nanoparticles (NPs) of C60 -RB are obtained. In vitro experiments indicate that C60 -RB NPs are capable of universal cellular uptake and lysosomal activation (pH 4.5–5.0), and they also exhibit excellent photodynamic therapeutic effect. The fluorescence turn-on and efficient singlet oxygen generation enabled by pH-activated C60 -RB NPs testify their great potential applications for cancer diagnosis and treatment.