On-Electrode Synthesis of Shape-Controlled Hierarchical Flower-Like Gold Nanostructures for Efficient Interfacial DNA Assembly and Sensitive Electrochemical Sensing of MicroRNA

Abstract

The performance for biomolecular detection is closely associated with the interfacial structure of a biosensor, which profoundly affects both thermodynamics and kinetics of the assembly, binding and signal transduction of biomolecules. Herein, it is reported on a one-step and template-free on-electrode synthesis method for making shape-controlled gold nanostructures on indium tin oxide substrates, which provide an electrochemical sensing platform for ultrasensitive detection of nucleic acids. Thus-prepared hierarchical flower-like gold nanostructures (HFGNs) possess large surface area that can readily accommodate the assembly of DNA probes for subsequent hybridization detection. It is found that the sensitivity for electrochemical DNA sensing is critically dependent on the morphology of HFGNs. By using this new strategy, a highly sensitive electrochemical biosensor is developed for label-free detection of microRNA-21 (miRNA-21), a biomarker for lung cancers. Importantly, it is demonstrated that this biosensor can be employed to measure the miRNA-21 expression level from human lung cancer cell (A549) lysates and worked well in 100% serum, suggesting its potential for applications in clinical diagnosis and a wide range of bioanalysis.

Integrated Microdroplets Array for Intelligent Electrochemical Fabrication

“…The gold nanostructures have attracted sustained attention in catalysis, sensing, and electronic field due to the diversified nanostructures 28–31. Electrochemical deposition is a traditional technique for fabricating gold nanostructures (e.g., nanoparticle, nanowires, nanoflowers, nanodendrites) 32–35. Therefore, we chose the electrochemical deposition of gold nanostructures as a model to verify feasibility and practicality of such platform.…”

Block Copolymer‐Derived Recessed Nanodisk‐Array Electrodes as Platforms for Folding‐Based Electrochemical DNA Sensors

“…The improvement of the detection sensitivity was possibly attributed to the steric and/or electrostatic restriction of the dynamic flexibility and orientation of the SLPs [17,25] within the nanopores having surface À COO À groups. [33,51] In addition, the enhancement of hybridization efficiency [10][11][12] within the RNE nanopores seemed to contribute to the sensitivity improvement, as shown by the slightly smaller K D values for the RNEbases sensors as compared with the film-free sensors ( Table 1). Of note, the effects of Γ* on K D and LOD were unclear at the Γ* range examined ( Figure S3) in contrast to a previous report that showed higher K D and lower LOD at E-DNA sensors with lower Γ*.…”

“…[5] Previously, nanostructured electrodes were used for electrochemical DNA sensors that measured hybridization-based signals using exogenous redox-active reagents. [8] These DNA sensors showed better detection sensitivity and selectivity because of larger faradaic signals originating from the high electrode surface [9,10] and also higher hybridization efficiency [10][11][12] and mitigated biofouling [13] due to the nanoscale electrode morphology. Nanostructured gold electrodes were also explored as the platforms of folding-based electrochemical sensors including E-DNA [14] and related aptamer-based sensors.…”

Multiple Amplified Electrochemical Detection of MicroRNA‐21 Using Hierarchical Flower‐like Gold Nanostructures Combined with Gold‐enriched Hybridization Chain Reaction

“…Xie's group developed an electrochemical biosensor based on oxidized single‐walled carbon nanotubes and nanodiamonds by using layer‐by‐layer assembly to expand the surface of the electrode and enhance electron transfer . Our group previously fabricated hierarchical flower‐like gold nanostructures (HFGNs)‐based substrate with well‐defined shape to provide large specific surface area, which was proven to be a promising electrochemical platform for the ultrasensitive target detection . Hybridization chain reaction (HCR) is a type of enzyme‐free isothermal nucleic amplification technique, in which successive hybridization events between two species of DNA hairpins can be triggered by an initiator sequence .…”