[12]aneN₃ Modified Tetraphenylethene Molecules as High-Performance Sensing, Condensing, and Delivering Agents toward DNAs

Abstract

Four [12]aneN3 modified tetraphenylethene (TPE) compounds with different numbers of polyamine units and structure configurations, namely 1, 2, 3, and 4, were designed and synthesized. All compounds showed strong aggregation-induced emission (AIE) features. Compounds 2 and 4 showed significant emission enhancement after the addition of ssDNAs and dsDNAs of different lengths as well as calf thymus DNA (ctDNA). Compounds 1 and 3 showed very poor fluorescent responses toward DNAs. Gel electrophoresis demonstrated the abilities of 1-4 to condense DNA effectively. Complete retardation of plasmid DNA can be achieved at a concentration of 25 μM (1), 8 μM (for 2 and 3) and 4 μM (4). Experiments including fluorescent contrastive titrations, scanning electron microscopy, dynamic laser scattering, EB displacement, and gel electrophoresis demonstrated that the four compounds were able to integrate with DNA through electrostatic interactions and supramolecular stacking. A vicinal configuration around TPE (2) and more triazole-[12]aneN3 recognition sites (4) evidently enhanced the sensing capability toward oligonucleotides, and the TPE unit played an important role in the plasmid DNA condensation process because of its strong binding. With the advantages of low cytotoxicity, effective DNA sensing, and DNA condensing properties, compound 4 was successfully applied as a nonviral DNA vector and fluorescent tracer for label-free gene delivery, which is the first example of a nonviral gene vector with AIE activity.

Synthesis and gene delivery properties of [12]aneN<sub>3</sub>-based nonviral gene vector with near infrared AIE activity

“…The vector as a deliver tracker showing on-demand reporting property was successfully applied to monitor the entire gene delivery process, providing spatiotemporal information regarding the translocation and intracellular fate of gene cargoes. This study suggests that integrating NIR AIE into [12]aneN3 is a promising strategy to achieve trackable gene delivery.…”

“…诊疗一体化等领域具有重要意义。 本文基于双 [12] 1 引言 将基因递送试剂和生物成像分子进行整合， 实现 治疗和诊断于一体的目标， 成为近年来研究多功能非 病毒基因载体的一个重要方向 [1] 。尽管在转染效率方 面，非病毒基因载体远远落后于病毒基因载体 [2] ，但 是非病毒基因载体具有易于制备，易于修饰和改造， 免疫原性低，生物安全性高等优势，使其成为病毒基 因载体最具潜力的替代品 [3] 。有机小分子荧光团具有 成本低、生物相容性好、灵敏度高以及信噪比(S/N) 高 [4] 等特性而成为一种具有潜力的无创造影剂。因 此， 近年来开发具有强荧光高分辨率的有机小分子荧 光非病毒基因载体引起了科学家们的广泛研究兴趣。 波长在 200 -650 nm 范围内的光学探针通常会 遇到组织自发荧光的强干扰、 高吸收和显著的光子散 射等问题 [5] ，因此，荧光发射在 600 -900 nm 范围 [6] ， 具有深层组织穿透性能并且能够实时进行追踪的近 红外(NIR)发光小分子成为近年来的研究热点 [7,8] 。 其中，聚集诱导发射(AIE)荧光团具有可以通过与 特异性的物种相互作用来激活荧光的特点， 使其最大 限度的减少非特异性干扰并改善空间精确度 [9,10] 。尽 管具有 NIR 发射 [11] 和 AIE 性能 [12,13] 的非病毒基因载 体均有报道，兼具 NIR 发射和 AIE 性能的单个载体 分子 [14,15] [15,16] 。 3 结果与讨论…”

“…AIE 类非病毒基因载体可以与 ctDNA 共聚集形 而增强载体分子的荧光 [16] 。因此，通过化合物 TPAH 的小牛胸腺 DNA(ctDNA)滴定荧光变化，能够评 估 TPAH 和 DNA 的结合能力。荧光滴定实验结果表 明随着 ctDNA 逐步滴加到 TPAH 的溶液中，溶液的 荧光强度逐渐增强。荧光强度在 ctDNA 为 60 μM 时 达到平衡，放大了 10 倍(图 S2) 。 油酰磷脂酰乙醇胺(DOPE)是一种中性磷脂， 可作为辅助脂质增加脂质类非病毒基因载体的转染 效率 [19] 。 根据我们使用 DOPE 的经验 [12,15,16]…”

“…AIE 载体仅在结合 DNA 时表现出荧光，与基因 分离后荧光消失， 这种响应性荧光增强有助于最大限 度地减少荧光团本身的荧光干扰， 从而提高示踪精确 度 [12] Abstract: Fluorescent nonviral gene vectors have drawn increasing research interests in trackable gene delivery, which could furnish important spatiotemporal information regarding the translocation and intracellular fate of gene cargoes, thus benefiting to understand the critical steps in determining the transfection efficiency. Herein, we report a triphenylamine derivative, TPAH, modified with [12]aneN3 and long hydrocarbon chain as a nonviral gene vector. TPAH bears typical near-infrared (NIR) aggregation-induced emission (AIE), and its resulting TPAH/dioleoylphosphatidylethanolamine (DOPE) liposome possesses strong DNA binding ability, capable of compacting nucleic acids into nanoparticles for gene delivery.…”

[12]aneN3-Conjugated AIEgens with two-photon imaging properties for synergistic gene/photodynamic therapy in vitro and in vivo

“…These results illustrated that the binding affinity slightly increased with the increase in the length of the bridged alkyl chain, similar to the results of gel electrophoresis assays. When compared to those in the literature, 36,37 the binding modes of those liposomes should be the combination of the intercalative interaction of TTC groups with base pairs of DNA and the electrostatic attraction of cationic [12]aneN 3 units with the negative phosphates of DNA.…”