Theophylline is a common bronchodilator for the treatment of diseases like asthma, bronchitis and emphysema. However, it should be strictly used and monitored due to its toxicity when the concentration is above certain levels. In this work, an electrochemical biosensor for theophylline detection is proposed by recognition of RNA aptamer and gold nanoparticle (AuNP)-based amplification technique. First, RNA aptamer is splitted into two single-stranded RNA probes. One is hybridized with DNA tetrahedron and the resulted nanostructure is then immobilized onto a gold electrode; the other is modified on the surface of AuNPs which is also labeled with methylene blue (MB) as electrochemical species. The recognition process between the two RNA probes and theophylline causes the localization of AuNPs and the enrichment of MB on the electrode interface. A significant electrochemical response is thus generated which is related to the concentration of initial theophylline. This proposed aptasensor shows excellent sensitivity and selectivity which could also be applied in quantitatively detection of theophylline in serums samples.

中文翻译：

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一种用于茶碱检测的高灵敏度金纳米颗粒电化学适体传感器

茶碱是一种常见的支气管扩张剂，用于治疗哮喘、支气管炎和肺气肿等疾病。但当浓度超过一定水平时，由于其毒性，应严格使用和监测。在这项工作中，通过识别 RNA 适配体和基于金纳米颗粒 (AuNP) 的扩增技术，提出了一种用于茶碱检测的电化学生物传感器。首先，RNA 适配子被分成两个单链 RNA 探针。一个与 DNA 四面体杂交，然后将所得纳米结构固定在金电极上；另一种修饰在 AuNPs 的表面，也用亚甲蓝 (MB) 作为电化学物种标记。两个 RNA 探针和茶碱之间的识别过程导致 AuNPs 的定位和 MB 在电极界面上的富集。因此产生与初始茶碱浓度有关的显着电化学响应。该适体传感器显示出优异的灵敏度和选择性，也可用于血清样品中茶碱的定量检测。