Caspase-3 is an important proteolytic enzyme that cleaves several key substrates in apoptotic processes, resulting in DNA fragmentation, the degradation of nuclear proteins, and the formation of apoptotic bodies. However, it is challenging to detect caspase-3 due to its low expression levels in cells. In this work, organic electrochemical transistors (OECTs) are used in the detection of caspase-3 for the first time. A self-assembled monolayer of the peptide is bonded to the Au gate electrode (GE) of an OECT via gold–sulphur bonds. It is found that the transfer curve of the transistor shifts to a lower gate voltage due to the modulation of the surface potential of the GE by the peptides. Then, the device is used in the detection of caspase-3 in aqueous solutions and shows a detection limit of 0.1 pM. Due to its high sensitivity, the device can detect caspase-3 in induced apoptotic HeLa cells. The system is low-cost, conveniently used and applicable for biological and medical monitoring where caspase-3 detection and quantification are required.

中文翻译：

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基于肽修饰的有机电化学晶体管生物传感器的caspase-3活性的高灵敏度检测

Caspase-3是一种重要的蛋白水解酶，可在凋亡过程中切割多个关键底物，导致DNA片段化，核蛋白降解以及凋亡小体的形成。但是，由于caspase-3在细胞中的低表达水平，因此检测caspase-3具有挑战性。在这项工作中，有机电化学晶体管（OECT）首次用于caspase-3的检测。该肽的自组装单层键合至OECT的金栅电极（GE）经由金硫债券。发现由于肽对GE的表面电势的调节，晶体管的转移曲线移至较低的栅极电压。然后，该设备用于检测水溶液中的caspase-3，检测限为0.1 pM。由于其高灵敏度，该设备可以检测诱导凋亡的HeLa细胞中的caspase-3。该系统价格低廉，使用方便，适用于需要caspase-3检测和定量的生物和医学监测。