Tailoring Photothermally Triggered Phase Transition of Multimodal Cascade Theranostics Platform by Spherical Nucleic Acids

Accurate targeting and low side effects are crucial for tumor theranostics. Herein, an in situ targeted therapy strategy which relies on a photothermally triggered theranostics nanoplatform is proposed. Taking advantage of spherical nucleic acids, black phosphorus nanosheets and zinc porphyrin metal-organic framework (PPF-1) nanosheets are programmed by DNA hybridization to result in a sandwich like structure. Its phase-transition temperature is finely tuned by altering the strand length and the proportion of (A + T) and (C + G) of the oligonucleotides. The superstructure can disassemble during photothermal therapy (PTT) process once the temperature reaches the melting point (T-m) of oligonucleotides duplex. Since the relief of fluorescence resonance energy transfer, the photothermally triggered photodynamic therapy can be realized under the irradiation of near-infrared laser. In turn, the enhanced singlet oxygen generation downregulates the heat shock proteins and thus improves the effect of PTT. Furthermore, the behaviors of superstructures in living cells and animals are elaborated by fluorescence and magnetic resonance imaging, and the in vivo therapy efficiency is also evaluated. This superstructure may establish a multiple synergistic platform for advanced cancer theranostics.

Automated summary

This study proposes an in situ targeted therapy strategy using a photothermally triggered nanoplatform. The nanoplatform, consisting of spherical nucleic acids, black phosphorus nanosheets, and zinc porphyrin metal-organic framework nanosheets, can disassemble during photothermal therapy, allowing for photothermally triggered photodynamic therapy. The enhanced singlet oxygen generation decreases heat shock proteins and improves the therapeutic effect. The superstructure shows potential as a synergistic platform for advanced cancer theranostics.