An aptasensor for detection of potassium ions based on RecJ_fexonuclease mediated signal amplification

Abstract

An electrochemical biosensor for potassium has been developed combining specific potassium-aptamer binding and RecJf exonuclease mediated signal amplification. Generally, the DNA probe with a stem-loop structure containing an anti-K(+) aptamer sequence is designed and modified on a gold electrode. K(+) can specifically bind to the aptamer and a G-quadruplex structure forms, which breaks the original stem-loop structure. The induced single-stranded 5' end can be further digested by RecJf exonuclease, releasing K(+) which can bind to another DNA probe on the electrode. After cycles of RecJf exonuclease cleavage initiated by K(+), the electrochemical signal intensity is significantly decreased, and can be used to determine the concentration of K(+). This aptasensor shows high sensitivity, selectivity as well as excellent stability and accuracy, which provides possibilities for further applications of K(+) assay in clinical diagnosis.

Reagentless, Structure-Switching, Electrochemical Aptamer-Based Sensors

“…This signaling limitation can be dramatically improved by adding a signal amplification technique that regenerates the redox molecule for amplified currents. While there are a several of examples of amplification coupled with aptamer recognition (76–79), these examples eliminate one of the most compelling attributes of E-AB sensors – their reagentless nature. An even more difficult task is to apply the amplification to one of the two sensor states – target-bound or unbound.…”

Target-driven self-assembly of stacking deoxyribonucleic acids for highly sensitive assay of proteins

“…By incorporating with signal amplification strategies [7][8][9], the employment of aptamer is opening new horizons for highly sensitive detection of proteins. Amongst these strategies, enzymeassisted nucleic acid amplification techniques, such as rolling circle amplification [10], isothermal strand displacement polymerization [11], and nuclease-aided recycling amplification [12][13][14] have proven powerful for achieving high sensitivity and have seen increasing use in recent years. However, the introduction of enzymes in the aptamer-based protein assays may bring additional limitations for clinical practice because enzymes are cost consuming and susceptible to contamination [15,16].…”

Nanosheet‐Stacked Chiral Silica Transcribed from Metal Ion‐ and pH‐Tuned Supramolecular Crystalline Complexes of Polyamine‐D‐Glucarate

“…As it is well known, aptamers refer to single‐stranded DNA or RNA oligonucleotides that can selectively bind to a broad range of targets, including metal ions, small molecules, peptides, proteins, and even complex targets such as whole cells and materials surfaces 22, 23. Aptamers are selected using systematic evolution of ligands by exponential enrichment (SELEX) 24, 25. Owing to numerous advantages such as high stability (especially DNA aptamers), small size, ease of modification, high binding affinity, high specificity and wide target range, aptamers are suitable candidates as recognition elements for the construction of biosensors 22, 26, 23–25.…”