Bio-inspired self-assembled bacteriochlorin nanoparticles for superior visualization and photothermal ablation of tumors

Abstract

Background: Although hyperthermia-based photothermal therapy (PTT) has achieved great success in the battle against malignant tumors, various commonly used photothermal sensitizers still suffer from non-selective tumor accumulation, limited photothermal conversion efficiency, potential toxicity and side effects, as well as complex and low cost-effective preparation process. Therefore, novel photothermal sensitizers are urgently required. The well-organized self-assembling of natural bacteriochlorophylls with superior photothermal property may provide an interesting option for the engineering of ideal PTS.

Methods: Inspired by the self-assembly peripheral light-harvesting antennas of natural bacteriochlorin in microorganisms, a biomimetic light-harvesting nanosystem (Nano-Bc) was developed via bacteriochlorophylls self-arranging in aqueous phase. The characterization of Nano-Bc were measured using DLS, TEM, UV-vis-near-infrared spectroscopy and preclinical PA imaging system. The cytotoxicity of Nano-Bc was quantitatively evaluated via a standard MTT assay using mouse breast cancer 4T1 cells, and the in vivo photothermal eradication of tumor was investigated in the 4T1 breast tumor-bearing mouse model.

Results: The obtained bacteriochlorin nanoparticles (Nano-Bc) exhibited ultra-high photothermal performance within the biological transparent window, showing superior heating capacity compared to commonly used photothermal sensitizers of organic dye indocyanine green and inorganic gold nanorods. Guiding by the inherent photoacoustic imaging of Nano-Bc, complete tumor elimination in vitro and vivo was evidenced upon laser irradiation.

Conclusion: The green and facile preparation, ultra-high photothermal effect in the transparent window, excellent photoacoustic imaging capacity, and great biosafety prompt, the bio-inspired Nano-Bc as a promising theranostic platform against cancer in the areas of healthcare.

Keywords: Bacteriochlorin; Biomimetics; Photoacoustic imaging; Photothermal therapy; Self-assembly.