Ultrasensitive MicroRNA Assay via Surface Plasmon Resonance Responses of Au@Ag Nanorods Etching

Abstract

Quantification of trace serum circulate microRNAs is extremely important in clinical diagnosis but remains a great challenge. Herein we developed an ultrasensitive platform for microRNA 141 (miR-141) detection based on a silver coated gold nanorods (Au@Ag NRs) etching process accompanied by surface plasmon resonance (SPR) shift. Both SPR absorption and scattering responses were monitored. Combined amplification cascades of catalyzed hairpin assembly (CHA) and hybridization chain reaction (HCR) with the sensitive SPR responses of plasmonic Au@Ag NRs, the proposed bioassay exhibited ultrahigh sensitivity toward miRNA-141 with dynamic range from 5.0 × 10 M to 1.0 × 10 M. With target concentration higher than 1.0 × 10 M, the color of the solution changed obviously that could be observed with naked eyes. Under dark-field microscopy observation of individual particle, a limit of detection down to 50 aM could be achieved. Owing to the superior sensitivity and selectivity, the proposed method was applied to detecting trace microRNA in serum. Similar SPR assays could be developed simply by redesigning the switching aptamer for the detections of other microRNAs or targets such as small molecule, DNA, or protein. Considering the convenient operation, good performance and simple observation modes of this method, it may have great potential in trace bioanalysis for clinical applications.

Plasmonic molecular assays: Recent advances and applications for mobile health

“…For example, Mirkin et al have pioneered on this format of assay using oligonucleotidefunctioned gold nanoparticles (Au NPs), which exhibit a strong red shift upon aggregation in the presence of target nucleotide [39,40], allowing rapid and sensitive readout with the naked eye or by an inexpensive optical device [41]. In addition to aggregation of NPs, colorimetric plasmon detection could also be demonstrated by growth or etching of NPs to generate colorimetric signal changes [22,42,43].…”

A DNAzyme-amplified DNA circuit for highly accurate microRNA detection and intracellular imaging

“…The efficiency of DNAzyme amplication could be improved by integrating its functional sequence with other amplication means. 12,13 Besides DNAzymes, the catalytic DNA circuit, including the hybridization chain reaction (HCR) [14][15][16] and catalyzed hairpin assembly (CHA), 17,18 is also emerging as a typical enzyme-free amplication strategy. The HCR mediates the target-initiated autonomous cross-opening of hairpin reactants for assembling long nicked dsDNA copolymers.…”

An exploration of nucleic acid liquid biopsy using a glucose meter

“…Therefore, if we decrease the amount of sucrose added to the product containing invertase, a higher concentration of miR-21 could be quantified. However, since the concentration of circulating miRNA in peripheral blood is mostly lower than 1.0 pM, 31 the detection range of this method under current conditions is suitable for liquid biopsy. For real analysis of miR-21 in serum or plasma, the specificity of the assay is a key parameter.…”