A signal amplification strategy and sensing application using single gold nanoelectrodes

Abstract

An electrochemical nanosensor was fabricated on a single gold nanoelectrode for thrombin sensing with high sensitivity via a signal amplification strategy.

Nanobioconjugates for Signal Amplification in Electrochemical Biosensing

“…Nanobioconjugates can be incorporated either to the transducer platform or to the signaling tag, always aiming to achieve an enhanced signal response as a result of the nanomaterial-biomolecules improved properties. In this context, an enhanced electrochemical response has been achieved by ultramicroelectrode arrays [ 73 , 74 ] and nanoelectrode arrangements [ 75 ]. The surface area is a critical aspect to be considered when assembling nanobioconjugates, i.e., the higher the surface area, the more biomolecules hosted and more amplified the signal response.…”

“…The use of complexes and dyes as signal amplifiers is a strategy widely employed in the biosensing field [ 86 , 133 , 134 ], where the electroactive complex or dye commonly intercalate (or adsorb) in the dsDNA through π-π stacking (or ionic interactions) [ 135 ]. For example, whereas dyes such as MB binds specifically with guanine bases from DNA due to its planar structure [ 136 ], the electroactive ruthenium complex adsorbs on the DNA sequences through DNA phosphate backbone-Ru 3+ electrostatic interactions [ 75 , 137 ]. The accumulation of numerous molecules of MB and Ru 3+ in the vicinity of the sensing surface and in between the DNA sequences produce a dramatically amplified response with no need for other mediators [ 75 ].…”

“…For example, whereas dyes such as MB binds specifically with guanine bases from DNA due to its planar structure [ 136 ], the electroactive ruthenium complex adsorbs on the DNA sequences through DNA phosphate backbone-Ru 3+ electrostatic interactions [ 75 , 137 ]. The accumulation of numerous molecules of MB and Ru 3+ in the vicinity of the sensing surface and in between the DNA sequences produce a dramatically amplified response with no need for other mediators [ 75 ].…”

Design of an Aptasensor Based on AuNPs@Fc-rGO for Detection of GPC3

“…In the study of electrochemical aptasensor. Ferrocene due to its good electrochemical activity, high electron transfer speed and excellent biocompatible are often used to enhance the performance of electrochemical sensor [4], and reduced graphene oxide (rGO) due to its porous surface structure and catalytic properties, can be used as a good carrier of Ferrocene (Fc) [5], Nanometallic particles, especially Au Nanoparticles (AuNPs), excellent electrocatalytic properties, high electrical conductivity and good biocompatibility [6], which can increase the loading of the immobilized biomolecules and facilitate the electron transfer between biological components and electrodes [7].…”

Analytes Triggered Conformational Switch of i-Motif DNA inside Gold-Decorated Solid-State Nanopores

“…The gold-decorated quartz nanopores were fabricated by UV irradiating the injected solution containing Triton X-100 and gold salt developed by us previously ( A ) . The cytosine-rich single-stranded DNA (ssDNA) was then immobilized on the gold film inside the nanopore by Au–S chemistry ( B ). − After adding Ag + to the solution under neutral pH conditions, the ssDNA was folded into a rigid quadruplex i-motif structure due to the interaction with Ag + ( C ). This transformation reduced the surface charge and changed the rigid structure of the nanopore tip, resulting in a decrease in the current–voltage response and ion rectification (ICR) ratio.…”