客户采用我司链霉亲和素磁珠（PuriMag G-Strep）在《Sensors and Actuators B: Chemical》发表SCI文章

S1 nuclease digestion-based rational truncation of PD-L1 aptamer and establishment of a signal dual amplification aptasensor

Sensors and Actuators B: Chemical ( IF 7.100 ) Pub Date : 2021-01-08 , DOI: 10.1016/j.snb.2021.129442
Hongwei Hu, Yujing Ding, Zihan Gao, Hao Li

Truncation optimization of aptamers can improve both specificity and robustness. At present, aptamer truncation is mainly performed based on predictions from molecular docking simulations, but this usually requires tedious trial-and-error and may result in false predictions. Here, we propose a strategy based on digestion by S1 nuclease to rationally truncate the aptamer, using the PD-L1-binding aptamer Apt80 as an example. Due to steric hindrance, recognition and binding regions between Apt80 and PD-L1 are not digested by the enzyme. The truncated form, Apt38, shows higher affinity and larger conformational change after binding, when compared to Apt80. The truncated Apt38 was used as a platform for developing a signal dual amplification fluorescence aptasensor using targeted recycling assisted by exonuclease I and qRT-PCR analysis. This aptasensor exhibited a high sensitivity toward PD-L1 with a limit of detection of 0.076 ng/mL in buffer system and 0.3625 ng/mL in human serum. Owing to its high sensitivity, specificity, ease operation and low cost for detection of PD-L1, this aptasensor should be useful in assisting clinicians to evaluate the status of cancer patient and to decide whether inhibitor drugs are needed.

中文翻译：
基于S1核酸酶消化的PD-L1适体的合理截断和信号双重扩增适体传感器的建立

适体的截短优化可以提高特异性和鲁棒性。目前，适体截短主要基于分子对接模拟的预测来进行，但这通常需要乏味的反复试验，并且可能导致错误的预测。在这里，我们提出一个基于S1核酸酶消化的策略，以PD-L1结合适体Apt80为例，合理地截断适体。由于空间位阻，Apt80和PD-L1之间的识别和结合区不会被酶消化。与Apt80相比，结合后的截短形式Apt38显示出更高的亲和力和更大的构象变化。截短的Apt38用作平台，用于通过核酸外切酶I和qRT-PCR分析辅助的靶向回收来开发信号双扩增荧光适体传感器。该适体传感器对PD-L1表现出高灵敏度，在缓冲液系统中的检出限为0.076 ng / mL，在人血清中的检出限为0.3625 ng / mL。由于其灵敏度高，特异性强，操作简便且检测PD-L1成本低，该适体传感器应有助于协助临床医生评估癌症患者的状况并决定是否需要抑制剂药物。

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