Theophylline is a popular drug for many respiratory diseases. However, certain toxic side effects may be developed and the narrow safety range raises the demand for sensitive methods to constantly monitor theophylline levels. This study presents an electrochemical approach towards theophylline detection based on the recognition by split RNA aptamers. Target induced construction of hand-in-hand RNA nanowire on the electrode surface could further absorb silver nanoparticles (Ag NPs) as electrochemical species. When theophylline is not present, RNA probes are stable and their conformations remain unchanged. In contrast, theophylline is able to trigger the hairpin opening of RNA probe and subsequent self-assembly of RNA nanowire, which could be captured by DNA tetrahedron on the electrode interface. After further decorating Ag NPs on the nanowire, silver stripping current is measured to reveal initial theophylline concentration. The developed sensing strategy shows excellent specificity and sensitivity with the limit of detection of 50 nM. Its practical utility is demonstrated by quantitative determination of theophylline levels in complex biological samples.

茶碱是许多呼吸系统疾病的流行药物。但是，可能会产生某些毒性副作用，狭窄的安全范围增加了对不断监测茶碱水平的敏感方法的需求。这项研究提出了一种基于分裂RNA适体识别的茶碱检测的电化学方法。在电极表面上靶诱导的手牵手RNA纳米线的构建可以进一步吸收银纳米颗粒（Ag NPs）作为电化学物质。当不存在茶碱时，RNA探针是稳定的，其构象保持不变。相反，茶碱能够触发RNA探针的发夹打开，并随后引起RNA纳米线的自组装，这可以被电极界面上的DNA四面体捕获。在纳米线上进一步装饰Ag NP之后，测量银剥离电流以揭示初始茶碱浓度。所开发的传感策略显示出出色的特异性和灵敏度，检测极限为50 nM。通过定量测定复杂生物样品中茶碱的含量证明了其实用性。