The ability to visualize and quantify apoptosis in vivo is critical to monitoring the disease response to treatment and providing prognostic information. However, the application of current apoptosis labeling probes faces significant challenges including nonspecific tissue uptake, inefficient apoptotic cell labeling and short monitoring windows. Here we report a highly specific apoptosis labeling nanoparticle (NP) probe with Pisum sativum agglutinin (PSA) as a tumor targeting ligand for prolonged in vivo apoptosis imaging. The NP (namely, IONP-Neu-PSA) consists of a magnetic iron oxide core (IONP) conjugated with PSA, and a reporter fluorophore. IONP-Neu-PSA demonstrated minimal cytotoxicity and high labeling specificity towards apoptotic cells in vitro. When applied in vivo, IONP-Neu-PSA tracks apoptotic tumors for a prolonged period of two weeks under near-IR imaging with low background noise. Moreover, IONP-Neu-PSA possesses T₂ contrast enhancing properties that can potentially enable apoptosis detection by magnetic resonance imaging (MRI). The high specificity for apoptotic cells, sustained fluorescence signals, and non-invasive imaging capability exhibited by IONP-Neu-PSA make it a versatile tool for cancer treatment monitoring and pathological research.

中文翻译：

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一种高度选择性的基于氧化铁的成像纳米颗粒，用于长期监测药物诱导的肿瘤细胞凋亡。

体内细胞凋亡的可视化和量化能力对于监测疾病对治疗的反应和提供预后信息至关重要。然而，当前凋亡标记探针的应用面临着重大挑战，包括非特异性组织摄取、凋亡细胞标记效率低和监测窗口短。在这里，我们报道了一种高度特异性的细胞凋亡标记纳米颗粒（NP）探针，以豌豆凝集素（PSA）作为肿瘤靶向配体，用于长时间的体内细胞凋亡成像。NP（即IONP-Neu-PSA）由与PSA结合的磁性氧化铁核心（IONP）和报告荧光团组成。IONP-Neu-PSA在体外对凋亡细胞表现出最小的细胞毒性和高标记特异性。当应用于体内时，IONP-Neu-PSA 在低背景噪声的近红外成像下可在长达两周的时间内追踪凋亡肿瘤。此外，IONP-Neu-PSA 具有T ₂对比增强特性，有可能通过磁共振成像 (MRI) 检测细胞凋亡。IONP-Neu-PSA 对凋亡细胞的高特异性、持续的荧光信号和非侵入性成像能力使其成为癌症治疗监测和病理研究的多功能工具。