Intramolecular Repulsive Interactions Enable High Efficiency of NIR-II Aggregation-Induced Emission Luminogens for High-Contrast Glioblastoma Imaging.

in ACS nano by Fulong Ma, Zhiyuan Gao, Qian Jia, Ying Yang, Bingzhe Wang, Jianyu Zhang, Ziwei Deng, Rufan Mo, Zeyang Ding, Guichuan Xing, Yong Liu, Zhongliang Wang, Kaikai Wang, Jacky W Y Lam, Dan Ding, Zheng Zhao, Ben Zhong Tang

TLDR

  • Scientists have developed a new class of NIR-II luminogens that can be used for high-contrast bioimaging and glioblastoma detection.
  • These luminogens show improved luminescence efficiency, twisted conformation, and AIE activity, making them promising for biomedical applications.

Abstract

Strategies to acquire high-efficiency luminogens that emit in the second near-infrared (NIR-II, 1000-1700 nm) range are still rare due to the impediment of the energy gap law. Herein, a feasible strategy is pioneered by installing large-volume encumbrances in a confined space to intensify the repulsive interactions arising from overlapping electron densities. The experimental results, including smaller coordinate displacement, reduced reorganization energy, and suppressed internal conversion, demonstrate that the repulsive interactions assist in the inhibition of radiationless deactivation. Meanwhile, the configuration and hybridization form of the donor units are transformed along with the repulsive interactions, bringing about improved oscillator strength. A 3.8-fold higher luminescence efficiency is realized via the synergistic effect. Furthermore, the repulsive interactions endow the NIR-II fluorophores with a highly twisted conformation, superior AIE activity, and cascaded improvement of fluorescence emission from isolated molecules to aggregates. By utilizing a brain-targeting peptide to functionalize the NIR-II nanoparticles, accurate detection and high-contrast imaging of orthotopic glioblastoma are realized. This work not only explores a fundamental principle to handle the intractable energy gap law but also provides potential applications of NIR-II luminogens in high-contrast bioimaging and glioblastoma detection.

Overview

  • The study pioneers a novel strategy to acquire high-efficiency luminogens that emit in the second near-infrared (NIR-II, 1000-1700 nm) range, overcoming the energy gap law obstacle.
  • The strategy involves installing large-volume encumbrances in a confined space to intensify repulsive interactions arising from overlapping electron densities.
  • The primary objective is to explore a fundamental principle to handle the intractable energy gap law and to provide potential applications of NIR-II luminogens in high-contrast bioimaging and glioblastoma detection.

Comparative Analysis & Findings

  • The experimental results demonstrate that repulsive interactions assist in the inhibition of radiationless deactivation, resulting in a 3.8-fold higher luminescence efficiency.
  • The repulsive interactions transform the configuration and hybridization form of the donor units, leading to improved oscillator strength.
  • The repulsive interactions endow the NIR-II fluorophores with a highly twisted conformation, superior AIE activity, and cascaded improvement of fluorescence emission from isolated molecules to aggregates.

Implications and Future Directions

  • This work has the potential to revolutionize high-contrast bioimaging and glioblastoma detection by providing a new class of NIR-II luminogens.
  • Future studies should focus on exploring ways to further enhance the luminescence efficiency and stability of these luminogens.
  • The utilization of brain-targeting peptides for functionalizing NIR-II nanoparticles holds promise for the development of novel imaging agents and therapeutic strategies.
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