Theranostics 2019; 9(1):20-33. doi:10.7150/thno.28857

Research Paper

Self-Luminescing Theranostic Nanoreactors with Intraparticle Relayed Energy Transfer for Tumor Microenvironment Activated Imaging and Photodynamic Therapy

Ming Wu1,4, Lingjie Wu1,4, Jiong Li1,3,4, Da Zhang1,4, Shanyou Lan1,2,4, Xiaolong Zhang1,4, Xinyi Lin1,4, Gang Liu5, Xiaolong Liu1,3,4 ✉, Jingfeng Liu1,2,3,4✉

1. The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou 350025, P.R. China
2. Liver Disease Center, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, P. R. China
3. Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P.R. China.
4. The Liver Center of Fujian Province, Fujian Medical University, Fuzhou 350025, P.R. China
5. Center for Molecular Imaging and Translational Medicine, Xiamen University, Xiamen 361005, P. R. China

Abstract

The low tissue penetration depth of external excitation light severely hinders the sensitivity of fluorescence imaging (FL) and the efficacy of photodynamic therapy (PDT) in vivo; thus, rational theranostic platforms that overcome the light penetration depth limit are urgently needed. To overcome this crucial problem, we designed a self-luminescing nanosystem (denoted POCL) with near-infrared (NIR) light emission and singlet oxygen (1O2) generation abilities utilizing an intraparticle relayed resonance energy transfer strategy.

Methods: Bis[3,4,6-trichloro-2-(pentyloxycarbonyl) phenyl] oxalate (CPPO) as a chemical energy source with high reactivity toward H2O2, poly[(9,9'-dioctyl-2,7-divinylene-fluorenylene)-alt-2-methoxy- 5-(2-ethyl-hexyloxy)-1,4-phenylene] (PFPV) as a highly efficient chemiluminescence converter, and tetraphenylporphyrin (TPP) as a photosensitizer with NIR emission and 1O2 generation abilities were coencapsulated by self-assembly with poly(ethyleneglycol)-co-poly(caprolactone) (PEG-PCL) and folate-PEG-cholesterol to form the POCL nanoreactor, with folate as the targeting group. A series of in vitro and in vivo analyses, including physical and chemical characterizations, tumor targeting ability, tumor microenvironment activated imaging and photodynamic therapy, as well as biosafety, were systematically investigated to characterize the POCL.

Results: The POCL displayed excellent NIR luminescence and 1O2 generation abilities in response to H2O2. Therefore, it could serve as a specific H2O2 probe to identify tumors through chemiluminescence imaging and as a chemiluminescence-driven PDT agent for inducing tumor cell apoptosis to inhibit tumor growth due to the abnormal overproduction of H2O2 in the tumor microenvironment. Moreover, the folate ligand on the POCL surface can further improve the accumulation at the tumor site via a receptor-mediated mechanism, thus enhancing tumor imaging and the therapeutic effects both in vitro and in vivo but without any observable systemic toxicity.

Conclusion: The nanosystem reported here might serve as a targeted, smart, precise, and noninvasive strategy triggered by the tumor microenvironment rather than by an outside light source for cancer NIR imaging and PDT treatment without limitations on penetration depth.

Keywords: self-luminescing theranostic nanoreactors, intraparticle relayed energy transfer, chemiluminescent imaging, PDT, H2O2

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How to cite this article:
Wu M, Wu L, Li J, Zhang D, Lan S, Zhang X, Lin X, Liu G, Liu X, Liu J. Self-Luminescing Theranostic Nanoreactors with Intraparticle Relayed Energy Transfer for Tumor Microenvironment Activated Imaging and Photodynamic Therapy. Theranostics 2019; 9(1):20-33. doi:10.7150/thno.28857. Available from http://www.thno.org/v09p0020.htm