基于金纳米粒子聚集与杂交链式扩增的microRNA传感

MicroRNA Sensing Based on Gold Nanoparticle Aggregation and Hybridization Chain Amplification

MicroRNA(miRNA)是癌症早期诊断的标志物,在生理和病理过程中发挥着关键作用,因此对miRNA的实时准确监测具有重要意义。目前,用于miRNA测定的信号放大/扩增策略多依赖于辅助酶的参与。本文建立了一种基于金纳米粒子(AuNPs)聚集和杂交链式反应(HCR)无酶扩增的高灵敏、特异性miRNA检测方法。为此,设计了一个辅助发夹探针(HP)和两个通用发夹探针(H1/H2),均为单链DNA(ssDNA)且具有粘性末端,可稳定水溶液中的AuNPs而有效防止盐诱导其聚集。靶miRNA与HP环区杂交,启动HCR触发双链DNA(dsDNA)聚合物的形成。dsDNA聚合物无粘性末端,对AuNPs的稳定能力减弱,从而产生盐诱导的AuNPs聚集,导致金胶体溶液由酒红色至蓝色的变化。据此可对miRNA进行光度法检测。该策略无需依赖酶促反应、分离过程及化学修饰,操作简单。通过设计HP环区序列,即可实现对不同靶标的检测,具有通用性。

MicroRNA(miRNA)is the marker for early diagnosis of cancer and plays a key role in physiological and pathological processes,therefore real-time and accurate monitoring of miRNA is of great significance.Currently,signal amplification/magnification strategies for miRNA assay are mostly dependent on the involvement of coenzymes.In this paper,a highly sensitive and specific miRNA detection method based on gold nanoparticle(AuNPs)aggregation and hybridization chain reaction(HCR)enzyme-free amplification is established.An assisted hairpin probe(HP)and two universal hairpin probes(H1/H2)are designed.Both of them are single-stranded DNA(ssDNA)with sticky ends,which could stabilize AuNPs in aqueous solution and effectively prevent salt-induced aggregation.The target miRNA hybridizes with the HP loop region,initiating HCR to trigger the formation of double-stranded DNA(dsDNA)polymers.The dsDNA polymer has no sticky ends and no ability to stabilize gold nanoparticles,resulting in salt-induced aggregation of AuNPs,and the change of gold-colloidal solution from wine red to blue.Thus,miRNA can be detected by spectrophotometry.This strategy does not rely on enzymatic reactions,separation processes,and chemical modifications,and operation is simple.By designing the HP loop sequence,the detection of different targets can be realized and show good versatility.