Acta Chimica Sinica ›› 2024, Vol. 82 ›› Issue (3): 265-273.DOI: 10.6023/A23100457 Previous Articles     Next Articles



赵玉强, 张霞, 杨芸如, 朱立平, 周莹*()   

  1. 云南大学 化学科学与工程学院 昆明 650091
  • 投稿日期:2023-10-19 发布日期:2023-12-27
  • 基金资助:
    国家自然科学基金(22067019); 国家自然科学基金(22367023); 云南省科技厅-云南大学联合特殊项目(202201BF070001-001); 云南大学研究生研究创新基金(KC-22222295)

Design and Synthesis of Aggregation-Induced Emission Photocage Molecules for In Situ Photoactivation Imaging Studies

Yu-Qiang Zhao, Xia Zhang, Yunru Yang, Liping Zhu, Ying Zhou*()   

  1. College of Chemical Science and Technology, Yunnan University, Kunming 650091, China
  • Received:2023-10-19 Published:2023-12-27
  • Contact: *E-mail:; Tel.: 18213063970
  • Supported by:
    National Natural Science Foundation of China(22067019); National Natural Science Foundation of China(22367023); Yunnan Provincial Science and Technology Department-Yunnan University Joint Special Project(202201BF070001-001); Postgraduate Research Innovation Foundation of Yunnan University(KC-22222295)

Two photoactivated fluorescent small molecule compounds, TPA-Tz1 and TPA-Tz2, were synthesized by incorporating a 1,2,4,5-tetrazine group into an aggregation-induced emission (AIE) fluorogen. Upon continuous UV light exposure, the fluorescence intensity of TPA-Tz1 and TPA-Tz2 increased by 167-fold and 100-fold, respectively. The photoactivation mechanism of the TPA-Tz1 solution was confirmed using high-resolution mass spectrometry, both before and after illumination, as part of standard verification procedures. The photoactivation mechanism involves the conversion of the tetrazine group to the cyanide group upon light exposure, leading to the restoration of fluorescence emission. Density functional theory (DFT) calculations revealed that the quenching mechanism of TPA-Tz1 involves energy transfer to dark states (ETDS). The fluorescence assessment of photoactivated TPA-CN1 products in solutions with varying water contents revealed distinct AIE characteristics. Specifically, a decline in fluorescence was evident at water contents below 50%, attributable to the twisted intramolecular charge transfer (TICT) effect. Conversely, as water content increased from 60% to 95%, a conspicuous blue shift and enhanced fluorescence were observed. Analysis of the excited states of its dimer, employing time-dependent density functional theory (TDDFT) hole charge analysis, underscored that charge transfer within the aggregated state predominantly accounted for the observed blue shift. The crystal structure of TPA-Tz1, obtained using a solvent evaporation method, unveiled its intricate internal stacked structure. The replacement of π-π interactions by hydrogen bonds and C—H…π interactions played a crucial role in maintaining both lattice stability and AIE. Moreover, cytotoxicity assessments conducted across diverse cell lines demonstrated the biocompatibility of TPA-Tz1, revealing a maximum cell inhibition rate of only 25.3%. Ultimately, photoactivated fluorescence imaging experiments were conducted on cells and Caenorhabditis elegans, utilizing a laser confocal imager for cells and a fluorescence microscope for the organism. The findings illustrated the capability of TPA-Tz1 to facilitate in situ photoactivation imaging at both the cellular and in vivo levels in multicellular organisms.

Key words: photocage, aggregation-induced emission, density functional theory, photoactivatable fluorescence, fluorescence imaging