Dual-triggered oxygen self-supply black phosphorus nanosystem for enhanced photodynamic therapy

Publication date: July 2018
Source:Biomaterials, Volume 172
Author(s): Jintong Liu, Ping Du, Hui Mao, Lei Zhang, Huangxian Ju, Jianping Lei
Nonspecific distribution of photosensitizer and the intrinsic hypoxic condition in the tumor microenvironment are two key factors limiting the efficacy of O2-dependent photodynamic therapy (PDT). Herein, a dual-triggered oxygen self-supported nanosystem using black phosphorus nanosheet (BPNS) as both photosensitizer and nanocarrier was developed to enhance PDT for tumors within hypoxic microenvironment. The BPNS platform was functionalized with folate and a blocker DNA duplex of 5′-Cy5-aptamer-heme/3′-heme labeled oligonucleotides. The resulting heme dimer could passivate its peroxidase activity. After specific recognition of aptamer-target, the quenched fluorescence is "turned" on by cellular adenosine triphosphate. The passivated nanosystem then activates the catalytic function towards excessive intracellular H2O2 to generate O2 essential to sustain BPNS-mediated PDT, leading to 8.7-fold and 7.5-fold increase of PDT efficacy in treating the hypoxic cell and tumor, respectively. Therefore, the dual-triggered oxygen self-supply nanosystem not only exerts tumor microenvironment-associated stimulus for enhanced PDT but also surmounts hypoxia-associated therapy resistance.



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