Organic Spherical Nucleic Acids for the Transport of a NIR‐II‐Emitting Dye Across the Blood–Brain Barrier

Organic Spherical Nucleic Acids for the Transport of a NIR‐II‐Emitting Dye Across the Blood–Brain Barrier:

A DNA block copolymer is used to produce a NIR‐II‐emitting nanofluorophore that can cross the brain–blood barrier (BBB), enabling non‐invasive fluorescence imaging of brain tumors. The dense DNA layer on the surface of the nanofluorophore encapsulates a NIR‐II‐emitting dye and transports it across the BBB using the receptor‐mediated transcytosis pathway.

Abstract

DNA nanotechnology plays an increasingly important role in the biomedical field; however, its application in the design of organic nanomaterials is underexplored. Herein, we report the use of DNA nanotechnology to transport a NIR‐II‐emitting nanofluorophore across the blood–brain barrier (BBB), facilitating non‐invasive imaging of brain tumors. Specifically, the DNA block copolymer, PS‐b‐DNA, is synthesized through a solid‐phase click reaction. We demonstrate that its self‐assembled structure shows exceptional cluster effects, among which BBB‐crossing is the most notable. Therefore, PS‐b‐DNA is utilized as an amphiphilic matrix to fabricate a NIR‐II nanofluorephore, which is applied in in vivo bioimaging. Accordingly, the NIR‐II fluorescence signal of the DNA‐based nanofluorophore localized at a glioblastoma is 3.8‐fold higher than the NIR‐II fluorescence signal of the PEG‐based counterpart. The notably increased imaging resolution will significantly benefit the further diagnosis and therapy of brain tumors.