Microribonucleic acids (miRNAs) are short noncoding ribonucleic acids that have been linked with a multitude of human diseases including lung, breast, and hematological cancers. In this work, we present a novel, extremely sensitive assay for the label-free optical biosensor-based detection of miRNAs, which is based on the oligonucleotide-triggered release of nanoparticles from a sensor surface. We combine this assay (herein referred to as the nanoparticle-release (NPR) assay) with a surface plasmon resonance biosensor and show that the assay is able to enhance the specific sensor response associated with the binding of target miRNA while suppressing the interfering effects caused by the non-specific binding. We apply the assay to the detection of miRNAs related to myelodysplastic syndromes (miR-125b, miR-16) in blood plasma and demonstrate that the assay enables detection of miR-125b with a limit of detection (LOD) of 349 aM (corresponding to the lowest detectable amounts of 419 zmol). The achieved LOD is better by a factor of ∼100 when compared to the conventional nanoparticle-enhanced sandwich assay. Moreover, we demonstrate that the NPR assay may be combined with time-division multiplexing for the multiplexed miRNA detection.

微核糖核酸 (miRNA) 是短的非编码核糖核酸，与多种人类疾病有关，包括肺癌、乳腺癌和血液癌。在这项工作中，我们提出了一种基于无标记光学生物传感器检测 miRNA 的新型、极其灵敏的检测方法，该检测方法基于寡核苷酸触发的纳米颗粒从传感器表面的释放。我们将此测定（在此称为纳米颗粒释放 (NPR) 测定）与表面等离子体共振生物传感器相结合，并表明该测定能够增强与目标 miRNA 结合相关的特定传感器响应，同时抑制引起的干扰效应通过非特异性结合。我们将该测定应用于检测与骨髓增生异常综合征相关的 miRNA（miR-125b，miR-16) 并证明该测定能够检测 miR-125b，检测限 (LOD) 为 349 aM（对应于 419 zmol 的最低可检测量）。与传统的纳米颗粒增强夹心法相比，获得的 LOD 提高了约 100 倍。此外，我们证明了 NPR 检测可以与时分多路复用相结合，用于多路复用 miRNA 检测。