Fluorescence bioimaging is very significant in studying biological processes. Fluorescent nanoparticles (NPs) manufactured from aggregation-induced emission (AIE) materials, as promising candidates, have attracted more attention. However, it is still a challenge to explore suitable AIE NPs for bioimaging. Herein, we synthesized pyrazoline-BODIPY (PZL-BDP) with a donor and acceptor (D-A) structure by a condensation reaction, cultured its single crystal, and studied its twisted intramolecular charge transfer (TICT) and AIE effects. PZL-BDP could self-assemble to form red fluorescent nanoparticles (PZL-BDP NPs) which showed a good fluorescence quantum yield of 15.8% in water. PZL-BDP NPs with excellent stability and biocompatibility exhibited a large Stokes shift (Δλ = 111 nm) which resulted in the reduction of external interference and enhancement of the fluorescence contrast. Furthermore, these nanoparticles could be readily internalized by HeLa cells and they stain the cells in just five seconds, indicating an ultrafast bioimaging protocol. Moreover, long-term tracking fluorescence signals in vivo for about 12 days were obtained. The bright red fluorescence, ultrafast cell staining ability, and long-term in vivo tracking competence outline the great potential of rational design nanomaterials with AIE characteristics for monitoring biological processes.

中文翻译：

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红色荧光吡唑啉-BODIPY纳米颗粒，用于超快和长期的生物成像。

荧光生物成像在研究生物过程中非常重要。由聚集诱导发射（AIE）材料制成的荧光纳米粒子（NP）作为有前途的候选者，已引起了更多关注。然而，探索合适的用于生物成像的AIE NP仍然是一个挑战。在这里，我们通过缩合反应合成了具有供体和受体（DA）结构的吡唑啉-BODIPY（PZL-BDPY），培养了其单晶，并研究了其扭曲的分子内电荷转移（TICT）和AIE效应。PZL-BDP可以自组装形成红色荧光纳米粒子（PZL-BDP NPs），在水中显示出15.8％的良好荧光量子产率。具有出色稳定性和生物相容性的PZL-BDP NP表现出较大的斯托克斯位移（Δλ= 111 nm），从而减少了外部干扰并增强了荧光对比度。此外，这些纳米粒子可以很容易地被HeLa细胞内在化，并且它们仅需五秒钟即可对细胞进行染色，这表明它具有超快的生物成像方案。而且，获得了体内约12天的长期跟踪荧光信号。鲜红色的荧光，超快的细胞染色能力以及长期的体内追踪能力概述了具有AIE特性的合理设计纳米材料在监测生物过程中的巨大潜力。指示超快的生物成像方案。而且，获得了体内约12天的长期跟踪荧光信号。鲜红色的荧光，超快的细胞染色能力以及长期的体内追踪能力概述了具有AIE特性的合理设计纳米材料在监测生物过程中的巨大潜力。指示超快速的生物成像方案。而且，获得了体内约12天的长期跟踪荧光信号。鲜红色的荧光，超快的细胞染色能力以及长期的体内追踪能力概述了具有AIE特性的合理设计纳米材料在监测生物过程中的巨大潜力。