The development of a low-cost and disposable biosensor platform for the sensitive and rapid detection of microRNAs (miRNAs) is of great interest for healthcare, pharmaceuticals, and medical science. We designed an impedimetric biosensing platform using Chitosan (CHIT)/nitrogen doped reduced graphene oxide (NRGO) conductive composite to modify the surface of pencil graphite electrodes (PGE) for the sensitive detection of miRNAs. An initial optimisation protocol involved investigation of the effect of NRGO concentration and miR 660 DNA probe concentration on the response of the modified electrode. After the optimization protocol, the sequence-selective hybridization between miR 660 DNA probe and its RNA target was evaluated by measuring changes on charge transfer resistance, Rct values. Moreover, the selectivity of impedimetric biosensor was tested in the presence of non-complementary miRNA (NC) sequences, such as miR 34a and miR 16. The hybridization process was examined both in phosphate buffer (PBS) and in PBS diluted fetal bovine serum (FBS:PBS) solutions. The biosensor demonstrated a detection limit of 1.72 μg/mL in PBS and 1.65 μg/mL in FBS:PBS diluted solution. Given the easy, quick and disposable attributes, the proposed conductive nanocomposite biosensor platform shows great promise as a low-cost sensor kit for healthcare monitoring, clinical diagnostics, and biomedical devices.

中文翻译：

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壳聚糖/氮掺杂还原氧化石墨烯修饰的生物传感器，用于 microRNA 的阻抗检测

用于敏感和快速检测 microRNA (miRNA) 的低成本和一次性生物传感器平台的开发对医疗保健、制药和医学科学具有重要意义。我们设计了一个阻抗生物传感平台，使用壳聚糖 (CHIT)/氮掺杂还原氧化石墨烯 (NRGO) 导电复合材料来修饰铅笔石墨电极 (PGE) 的表面，以灵敏地检测 miRNA。初始优化方案涉及研究 NRGO 浓度和 miR 660 DNA 探针浓度对修饰电极响应的影响。在优化方案之后，通过测量电荷转移电阻 Rct 值的变化来评估 miR 660 DNA 探针与其 RNA 靶标之间的序列选择性杂交。而且，在存在非互补 miRNA (NC) 序列，例如 miR 34a 和 miR 16 的情况下测试了阻抗生物传感器的选择性。 在磷酸盐缓冲液 (PBS) 和 PBS 稀释的胎牛血清 (FBS: PBS) 溶液。该生物传感器在 PBS 中的检测限为 1.72 μg/mL，在 FBS:PBS 稀释溶液中的检测限为 1.65 μg/mL。鉴于简单、快速和一次性的特性，所提出的导电纳米复合生物传感器平台显示出作为用于医疗监测、临床诊断和生物医学设备的低成本传感器套件的巨大前景。该生物传感器在 PBS 中的检测限为 1.72 μg/mL，在 FBS:PBS 稀释溶液中的检测限为 1.65 μg/mL。鉴于简单、快速和一次性的特性，所提出的导电纳米复合生物传感器平台显示出作为用于医疗监测、临床诊断和生物医学设备的低成本传感器套件的巨大前景。该生物传感器在 PBS 中的检测限为 1.72 μg/mL，在 FBS:PBS 稀释溶液中的检测限为 1.65 μg/mL。鉴于简单、快速和一次性的特性，所提出的导电纳米复合生物传感器平台显示出作为用于医疗监测、临床诊断和生物医学设备的低成本传感器套件的巨大前景。