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Integration of exonuclease III-powered three-dimensional DNA walker with single-molecule detection for multiple initiator caspases assay
Chemical Science ( IF 7.6 ) Pub Date : 2021-11-08 , DOI: 10.1039/d1sc05115f
Meng Liu 1 , Rui Xu 1 , Wenjing Liu 2 , Jian-Ge Qiu 2 , Yan Wang 1 , Fei Ma 3 , Chun-Yang Zhang 1
Affiliation  

Initiator caspases are important components of cellular apoptotic signaling and they can activate effector caspases in extrinsic and intrinsic apoptotic pathways. The simultaneous detection of multiple initiator caspases is essential for apoptosis mechanism studies and disease therapy. Herein, we develop a sensitive nanosensor based on the integration of exonuclease III (Exo III)-powered three-dimensional (3D) DNA walker with single-molecule detection for the simultaneous measurement of initiator caspase-8 and caspase-9. This assay involves two peptide–DNA detection probe-conjugated magnetic beads and two signal probe-conjugated gold nanoparticles (signal probes@AuNPs). The presence of caspase-8 and caspase-9 can induce the cleavage of peptides in two peptide–DNA detection probes, releasing two trigger DNAs from the magnetic beads, respectively. The two trigger DNAs can serve as the walker DNA to walk on the surface of the signal probes@AuNPs powered by Exo III digestion, liberating numerous Cy5 and Texas Red fluorophores which can be quantified by single-molecule detection, with Cy5 indicating caspase-8 and Texas Red indicating caspase-9. Notably, the introduction of the AuNP-based 3D DNA walker greatly reduces the background signal and amplifies the output signals, and the introduction of single-molecule detection further improves the detection sensitivity. This nanosensor is very sensitive with a detection limit of 2.08 × 10−6 U μL−1 for caspase-8 and 1.71 × 10−6 U μL−1 for caspase-9, and it can be used for the simultaneous screening of caspase inhibitors and the measurement of endogenous caspase activity in various cell lines at the single-cell level. Moreover, this nanosensor can be extended to detect various proteases by simply changing the peptide sequences of the detection probes.

中文翻译:


核酸外切酶 III 驱动的三维 DNA 步行器与单分子检测的集成,用于多起始子半胱天冬酶测定



起始半胱天冬酶是细胞凋亡信号传导的重要组成部分,它们可以激活外在和内在凋亡途径中的效应半胱天冬酶。同时检测多个启动子半胱天冬酶对于细胞凋亡机制研究和疾病治疗至关重要。在此,我们开发了一种基于核酸外切酶 III (Exo III) 驱动的三维 (3D) DNA 步行器与单分子检测集成的灵敏纳米传感器,用于同时测量起始子 caspase-8 和 caspase-9。该测定涉及两个肽-DNA 检测探针缀合的磁珠和两个信号探针缀合的金纳米颗粒(信号探针@AuNPs)。 caspase-8 和 caspase-9 的存在可以诱导两个肽-DNA 检测探针中肽的裂解,分别从磁珠中释放两个触发 DNA。两条触发DNA可以作为步行DNA在Exo III消化驱动的信号探针@AuNPs表面行走,释放大量的Cy5和德克萨斯红荧光团,这些荧光团可以通过单分子检测进行定量,其中Cy5指示caspase-8和德克萨斯红表示 caspase-9。值得注意的是,基于AuNP的3D DNA walker的引入大大降低了背景信号并放大了输出信号,并且单分子检测的引入进一步提高了检测灵敏度。该纳米传感器非常灵敏,对于 caspase-8 和 1 的检测限为 2.08 × 10 -6 U μL -1 。71 × 10 -6 U μL -1 for caspase-9,可用于在单细胞水平同时筛选Caspase抑制剂和测量各种细胞系的内源性Caspase活性。此外,通过简单地改变检测探针的肽序列,该纳米传感器可以扩展到检测各种蛋白酶。
更新日期:2021-11-22
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