Li et al. interlinked rolling circle polymerization and rolling circle transcription, which offered dual amplification for surface enhanced Raman scattering detection of miRNA. [11] Ge et al. realized miRNA induced hybridization chain reaction on a tetrahedral DNA modified electrode, which captured multiple catalytic enzymes in a highly ordered way for signal generation.Nanobiotechnology is an emerging area of research which has attracted much interest. [12,13] Nanomaterials with miniaturized sizes always possess completely new or enhanced physico-chemical properties and offer potential functions. [14,15] Gold nanoparticles (AuNPs) are a kind of representative nanomaterials, which have been extensively exploited for applications on various fronts including biosensors, drug delivery, and pharmaceutical studies. [16][17][18][19] AuNPs possess many fantastic properties including strong surface-plasmon resonance absorptions, high extinction coefficients, excellent electrical conductivity, huge specific surface area, high biocompatibility, and so on. [20] Thus, AuNPs-based biosensors have been widely developed for the assay of metal ions, [21] nucleic acids, [22] proteins, [23] and cells [24] in the past decade. In addition, AuNPs can also been conjugated with other nanomaterials for analytical purposes, such as graphene oxide, [25] silver NPs, [26] magnetic NPs, [27,28] rare earth-doped upconversion NPs, [29] and so on.In this contribution, we have developed a colorimetric biosensor for miRNA detection based on adamantane derivatives functionalized AuNPs coupled with strand displacement reaction, an effective isothermal amplification technique. [30] 7-hydroxycarbonyl-2,4,9-trithiaadmantane is firstly synthesized, which can be confirmed by 1 H NMR spectrum and mass spectrum ( Figures S1 and S2, Supporting Information). This adamantane derivative contains three thiol vertices, which can strongly interact with gold surface. Therefore, it can be firmly immobilized on the surface of AuNPs. Taking advantage of triple gold-sulfur interactions, the modified AuNPs are highly stable and become protein-resistant, which is suitable for enzyme-based signal amplification. Moreover, due to the carboxyl group of 7-hydroxycarbonyl-2,4,9-trithiaadmantane, the modified AuNPs can be further functionalized with aminated DNA probes (Figure 1a). We have then developed a sensing strategy for miRNA detection based on the functionalized AuNPs and strand displacement amplification. As illustrated in Figure 1b, DNA probe 1 contains a hairpin structure and DNA probe 2 is a single strand. The two aminated DNA probes are MiRNAs are riveting RNA molecules due to their close relevance to the regulation of gene expression and certain physiological or pathological processes. Rapid and sensitive methods for miRNA assay are essential for biological researches and clinical diagnosis of many diseases. In this work, gold nanoparticles (AuNPs) have been modified with adamantane derivatives and then Dwith NA probes for colorimetric detection of miRNA. Target...
