Department of Analytical, Environmental & Forensic Sciences, Faculty of Life Sciences & Medicine, King's College London, London SE1 9NH, UK.
Biosensors (Basel). 2024 Oct 17;14(10):509. doi: 10.3390/bios14100509.
Fluorescence-based aptasensors have been regarded as innovative analytical tools for the detection and quantification of analytes in many fields, including medicine and therapeutics. Using DNA aptamers as the biosensor recognition component, conventional molecular beacon aptasensor designs utilise target-induced structural switches of the DNA aptamers to generate a measurable fluorescent signal. However, not all DNA aptamers undergo sufficient target-specific conformational changes for significant fluorescence measurements. Here, the use of complementary 'antisense' strands is proposed to enable fluorescence measurement through strand displacement upon target binding. Using a published target-specific DNA aptamer against the receptor binding domain of SARS-CoV-2, we designed a streptavidin-aptamer bead complex as a fluorescence displacement assay for target detection. The developed assay demonstrates a linear range from 50 to 800 nanomolar (nM) with a limit of detection calculated at 67.5 nM and a limit of quantification calculated at 204.5 nM. This provides a 'fit-for-purpose' model assay for the detection and quantification of any target of interest by adapting and functionalising a suitable target-specific DNA aptamer and its complementary antisense strand.
基于荧光的适体传感器已被视为在许多领域（包括医学和治疗学）中用于检测和定量分析物的创新分析工具。使用 DNA 适体作为生物传感器识别组件，传统的分子信标适体传感器设计利用 DNA 适体的靶标诱导结构开关来产生可测量的荧光信号。然而，并非所有 DNA 适体都能发生足够的靶标特异性构象变化以进行显著的荧光测量。在这里，提出使用互补的“反义”链来通过靶标结合时的链置换来实现荧光测量。使用针对 SARS-CoV-2 的受体结合域的已发表的靶标特异性 DNA 适体，我们设计了一种链霉亲和素-适体珠复合物作为荧光置换测定法用于靶标检测。所开发的测定法显示出从 50 到 800 纳摩尔（nM）的线性范围，检测限计算为 67.5 nM，定量限计算为 204.5 nM。通过适配和功能化合适的靶标特异性 DNA 适体及其互补反义链，为任何感兴趣的靶标的检测和定量提供了一种“适用”的模型测定法。
