DNA Nanostructure-Based Magnetic Beads for Potentiometric Aptasensing

Abstract

In this work, a simple, general, and sensitive potentiometric platform is presented, which allows potentiometric sensing to be applied to any class of molecule irrespective of the analyte charge. DNA nanostructures are self-assembled on magnetic beads via the incorporation of an aptamer into a hybridization chain reaction. The aptamer− target binding event leads to the disassembly of the DNA nanostructures, which results in a dramatic change in the surface charge of the magnetic beads. Such a surface charge change can be sensitively detected by a polycation-sensitive membrane electrode using protamine as an indicator. With an endocrine disruptor bisphenol A as a model, the proposed potentiometric method shows a wide linear range from 0.1 to 100 nM with a low detection limit of 80 pM (3σ). The proposed sensing strategy will lay a foundation for the development of potentiometric sensors for highly sensitive and selective detection of various targets.

Potentiometric Aptasensing of Vibrio alginolyticus Based on DNA Nanostructure-Modified Magnetic Beads

“…The aptamer and H1/H2 DNA hybridize successively with the capture DNA through the complementary base-pairing reactions to form the DNA nanostructure-modified magnetic beads. In the presence of the target, the aptamer on the DNA nanostructure-modified magnetic beads specifically binds to the target, which leads to the disassembly of the DNA nanostructures and subsequently influences the charge or DNA concentration on the magnetic beads [28]. This aptamer/target binding event can be detected by the solid-contact polycation-sensitive electrode using protamine as an indicator, based on the electrostatic interaction between the DNA nanostructures and protamine.…”

“…The DNA nanostructure-modified magnetic beads were prepared as described before [28]. The capture DNA modified magnetic beads were obtained by incubating 150 μL of 5’-biotin-modified capture DNA fragments (3 μM) with 150 μL of streptavidin modified magnetic beads (10 mg·mL −1 ) via shaking for 0.5 h. After magnetic separation and washing with buffer, the capture DNA modified magnetic beads were incubated with 150 μL of aptamer DNA fragments (3 μM) via shaking for 1 h, and the capture/aptamer DNA modified magnetic beads were thus obtained.…”

Paper-based microfluidic sampling and separation of analytes for potentiometric ion sensing

“…This approach, however, requires sophisticated and relatively expensive instrumentation. Furthermore, pre-concentration and matrix elimination procedures based on electrochemical accumulation, magnetic sep-aration or paper-based filtration are alternative choices to enhance the performance of ISEs for potentiometric measurements [8][9][10][11]. In all these methods, medium exchange is an essential step for subsequent potentiometric detection, which has the drawbacks of tedious measurement protocols.…”

Pulsed galvanostatic control of a solid-contact ion-selective electrode for potentiometric biosensing of microcystin-LR

“…In recent years, potentiometry based on ion-selective electrodes (ISEs) have evolved to provide a promising transducer for biosensing [22][23][24][25][26]. Typically, these electrodes have been extensively investigated for biosensing via zero-current potentiometry.…”