A pH-independent electrochemical aptamer-based biosensor supports quantitative, real-time measurement in vivo

Abstract

The development of biosensors capable to achieve accurate and precise molecular measurements in the living body under pH-variable biological environments (e. g. subcellular organelles, biological fluids and organs) plays a...

Electrochemical Aptamer-Based Sensors with Tunable Detection Range

“…The signal of E-AB sensors is produced based on the redox reaction of the redox reporters modified on the aptamers . Thus, the distribution (for example the density) of the aptamers on the surface of the electrode could impact the detection performance of the E-AB sensors.…”

“…The signal of E-AB sensors is produced based on the redox reaction of the redox reporters modified on the aptamers. 49 Thus, the distribution (for example the density) of the aptamers on the surface of the electrode could impact the detection performance of the E-AB sensors. The reason may lie in the different amount and accessibility of the binding sites on the electrodes with different aptamer distributions.…”

Real-Time, In Vivo Molecular Monitoring Using Electrochemical Aptamer Based Sensors: Opportunities and Challenges

“…18 While the electron transfer kinetics of this reporter species depend upon pH, 19 limiting its application to media with stable pH, new redox reporters are being explored that do not display such dependence. 20 Finally, the sensor is fabricated by attaching the redox-reporter-modified aptamer to a gold electrode via the formation of a thiol-on-gold bond, followed by "backfilling" with an alkanethiol to form a stable, self-assembled monolayer (Figure 1B). Any new sensors created are validated in vitro prior to in vivo applications.…”

“…Of the redox reporters explored, methylene blue has proven the most popular due to its stability under repeated electrochemical interrogation . While the electron transfer kinetics of this reporter species depend upon pH, limiting its application to media with stable pH, new redox reporters are being explored that do not display such dependence . Finally, the sensor is fabricated by attaching the redox-reporter-modified aptamer to a gold electrode via the formation of a thiol-on-gold bond, followed by “backfilling” with an alkanethiol to form a stable, self-assembled monolayer (Figure B).…”

Os(ii/iii) complex supports pH-insensitive electrochemical DNA-based sensing with superior operational stability than the benchmark methylene blue reporter

“…Only recently, Li et al published a novel reporter based on tetrathiafulvalene that has a positive formal reduction potential, , and undergoes pH-independent electron transfer. 21 However, the radical-based mechanism of electron transfer in this molecule may promote secondary chemical reactions with species present in commonly used buffers as well as biomolecules present in biological fluids such as serum or blood, limiting its ability to support long-term sensor operation. Further studies are needed to conclusively determine the value of this reporter for continuous molecular monitoring.…”