Microchimica Acta ( IF 5.3 ) Pub Date : 2021-08-06 , DOI: 10.1007/s00604-021-04940-9 Ling-Ling Shang 1 , Xiaojie Song 1 , Chang-Bin Niu 1 , Qi-Yan Lv 1 , Chun-Ling Li 1 , Hui-Fang Cui 1 , Shoutao Zhang 1
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A sensitive and turn-on fluorescence nanoprobe based on core-shell Ag@Au nanoparticles (Ag@AuNPs) as a fluorescence receptor and red emissive graphene quantum dots (GQDs) as a donor was fabricated. They were conjugated together through π-π stacking between the GQDs and single-strand DNA modified at the Ag@AuNPs surface. The absorption spectrum of the receptor significantly overlapped with the donor emission spectrum, leading to a strong Förster resonance energy transfer (FRET) and thus a dramatic quenching. The sensing mechanism relies on fluorescence recovery following DNA cleavage by •OH produced from Fenton-like reaction between the peroxidase-like Ag nanocore and H2O2. The red emissive feature (Ex/Em, 520 nm/560 nm) provides low background in physiological samples. The •OH production, great spectrum overlapping, and red emission together contributes to good sensitivity and living cell imaging capability. The fluorescence assay (intensity at 560 nm) achieves a low detection limit of 0.49 μM H2O2 and a wide linear range from 5 to 200 μM, superior to most of the reported fluorescent probes. The RSD value for 100 μM H2O2 was 1.4%. The nanoprobe exhibits excellent anti-interferences and shows low cytotoxicity. The recovery of 100 μM standard H2O2 in a cancer cell lysate was 85.8%. Most satisfactorily, it can realize monitoring and imaging H2O2 in living cells. This study not only presents a sensitive H2O2 probe but also provides a platform for detecting other types of reactive oxygen species.
Graphical abstract
中文翻译：
基于 Ag@Au 纳米颗粒和石墨烯量子点的红色荧光纳米探针用于 H2O2 测定和活细胞成像
制备了一种基于核壳型 Ag@Au 纳米粒子 (Ag@AuNPs) 作为荧光受体和红色发射石墨烯量子点 (GQDs) 作为供体的灵敏且开启的荧光纳米探针。它们通过 GQDs 和在 Ag@AuNPs 表面修饰的单链 DNA 之间的 π-π 堆积结合在一起。受体的吸收光谱与供体发射光谱显着重叠，导致强烈的 Förster 共振能量转移 (FRET)，从而导致剧烈的猝灭。传感机制依赖于过氧化物酶样 Ag 纳米核与 H 2 O 2之间的类芬顿反应产生的 •OH 裂解 DNA 后的荧光恢复. 红色发射特征（Ex/Em，520 nm/560 nm）在生理样品中提供低背景。•OH 产生、光谱重叠和红色发射共同有助于实现良好的灵敏度和活细胞成像能力。荧光测定（560 nm 处的强度）实现了 0.49 μM H 2 O 2的低检测限和 5 至 200 μM 的宽线性范围，优于大多数报道的荧光探针。100 μM H 2 O 2的 RSD 值为1.4%。纳米探针表现出优异的抗干扰性和低细胞毒性。癌细胞裂解物中 100 μM 标准 H 2 O 2的回收率为 85.8%。最满意的是，它可以实现监控和成像H2 O 2在活细胞中。本研究不仅提供了一种灵敏的 H 2 O 2探针，而且还为检测其他类型的活性氧提供了一个平台。
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