Amplified Surface Plasmon Resonance Based DNA Biosensors, Aptasensors, and Hg²⁺ Sensors Using Hemin/G‐Quadruplexes and Au Nanoparticles

Abstract

Thiolated nucleic acid hairpin nanostructures that include in their stem region a "caged" G-quadruplex sequence, and in their single-stranded loop region oligonucleotide recognition sequences for DNA, adenosine monophosphate (AMP), or Hg(2+) ions were linked to bare Au surfaces or to Au nanoparticles (NPs) linked to Au surfaces. The opening of the hairpin nanostructures associated with the bare Au surface by the complementary target DNA, AMP substrate, or Hg(2+) ions, in the presence of hemin, led to the self-assembly of hemin/G-quadruplexes on the surface. The resulting dielectric changes on the surface exhibited shifts in the surface plasmon resonance (SPR) spectra, thus providing a readout signal for the recognition events. A similar opening of the hairpin nanostructures, immobilized on the Au NPs associated with the Au surface, by the DNA, AMP, or Hg(2+) led to an ultrasensitive SPR-amplified detection of the respective analytes. The amplification originated from the coupling between the localized surface plasmon associated with the NPs and the surface plasmon wave, an effect that cooperatively amplifies the SPR shifts that result from the formation of the hemin/G-quadruplexes. The different sensing platforms reveal impressive sensitivities and selectivities toward the target analytes.

Highly sensitive electrochemical detection of mercury (II) via single ion-induced three-way junction of DNA

“…However, these simple methods need multiple T-Hg 2+ -T coordination for forming one DNA switch structure, which limits their sensitivity. Thus different amplification strategies [22], such as exonuclease mediated metal ion cyclical reshuffling [18], have recently been employed to improve the detection sensitivity. However, the amplification steps increase the complexity of analytical procedures with strict detection conditions, prolong the assay time, and sometimes produce high background.…”

Mass effect of redox reactions: A novel mode for surface plasmon resonance-based bioanalysis

“…Remarkably, an in vitro determination of prostate specific antigen down to 300 aM was achieved by the probe of superparamagnetic microbeads (Yao et al, 2013). Nevertheless, so far only special microscopic shapes consisting of certain elements are qualified for the responding sensitization of SPR-based bioanalyses (Pelossof et al, 2012); more than that, it is apparent to be a standard protocol for surface biofunctionalization of applied materials. Both take negative impact on the flexibility and the cost-effectiveness of SPR platform.…”

Recent trends in SELEX technique and its application to food safety monitoring

“…Several classic aptamers, including Pb 2+ [10], Hg 2+ [11], ochratoxin A [12], and tetracycline [13] have been successfully selected with SELEX and applied in food safety monitoring [14]. With respect to these aptamer-based applications, they could be divided into affinity chromatography [15], capillary electrophoresis [16], mass spectrometry [17] and biosensors [18] based methods et al…”