SwissKnife-Inspired Multifunctional Fluorescence Probes for Cellular Organelle Targeting Based on Simple AIEgens

Facile,
efficient, and mass production of aggregation-induced emission
(AIE) luminogens (AIEgens) with excited-state intramolecular proton
transfer (ESIPT) characteristics was achieved by a one-step condensation
reaction of 2-(hydrazonomethyl)­phenol with benzaldehydes. The function
of as-prepared AIEgens could be tuned easily by varying the functional
group being carried on the phenyl ring of benzaldehyde just like a
Swiss knife handle. The suitable distance and angle of the intramolecular
hydrogen bond in these AIEgens endowed them with ESIPT properties,
intense solid-state luminescence, and large Stokes shifts (155–169
nm). These AIEgens could not only serve as biological probes showing
specific targeting to lipid droplets, endoplasmic reticulum, and lysosomes,
respectively, but also generate reactive oxygen species upon visible
light irradiation to make them promise for photodynamic therapy.

本研究通过2-(腙甲基)苯酚与苯甲醛类化合物的一步缩合反应，成功实现了具备激发态分子内质子转移（excited-state intramolecular proton transfer, ESIPT）特性的聚集诱导发光（aggregation-induced emission, AIE）发光体（AIE luminogens, AIEgens）的简便、高效规模化制备。所制备的AIE发光体的功能可通过调控苯甲醛苯环上所携带的官能团实现简便调节，恰似瑞士军刀刀柄般灵活适配。这类AIE发光体分子内氢键的适宜间距与夹角赋予了其ESIPT特性、强烈的固态发光性能以及155~169 nm的大斯托克斯位移。这些AIE发光体不仅可分别作为特异性靶向脂滴、内质网与溶酶体的生物探针，还可在可见光照射下产生活性氧物种，因此具备应用于光动力治疗的潜力。