A new dual-signalling electrochemical aptasensor with the integration of “signal on/off” and “labeling/label-free” strategies

Electrochemical Biosensors in Point‐of‐Care Devices: Recent Advances and Future Trends

“…In electrochemical aptasensors, proper attachment of the aptamer to the electrode surface is very important. To achieve this, one of the most common strategies is the addition of thiol groups on either the 3′ or 5′ end through chemical reaction, which can, for example, facilitate direct immobilization on gold electrodes . Immobilization via biotin‐streptavidin interactions or physical adsorption are other strategies currently employed .…”

“…The signals for MB−P release, Fc−P approaching the electrode surface and the presence of the target molecule (BPA) itself were recorded by square wave voltammetry (SWV). More recently, Cao and co‐workers showed another interesting strategy for the development of a versatile electrochemical aptasensor with dual‐signaling using lysozyme (Lys) as a model target . In this report, ferrocene‐labeled single‐stranded DNA (Fc−P) with an alkanethiol group at the 5′ end (used to attach the DNA strand to the surface of the gold electrode) is hybridized to a specific Lys aptamer to create the electrochemical aptasensor (Figure b).…”

“…To achieve this, one of the most common strategies is the addition of thiol groups on either the 3' or 5' end through chemical reaction, which can, for example, facilitate direct immobilization on gold electrodes. [78] Immobilization via biotin-streptavidin interactions or physical adsorption are other strategies currently employed. [79] In electrochemical aptasensors, the transduction signal can be divided in voltammetric, amperometric, potentiometric, impedimetric or conductometric, depending on the parameters measured, such as current and potential, current alone, potential alone, impedance, or conductance, respectively.…”

“…More recently, Cao and co-workers showed another interesting strategy for the development of a versatile electrochemical aptasensor with dual-signaling using lysozyme (Lys) as a model target. [78] In this report, ferrocene-labeled single-stranded DNA (FcÀP) with an alkanethiol group at the 5' end (used to attach the DNA strand to the surface of the gold electrode) is hybridized to a specific Lys aptamer to create the electrochemical aptasensor (Figure 4b). The presence of lysozymes in the samples promotes the removal of the aptamer strip, causing changes in the conformation of the immobilized complementary strand containing the ferrocene label, as in the previous example.…”

An ultrasensitive and label-free electrochemical DNA biosensor for detection of DNase I activity

“…This sensor can fall into single signaling electrochemical type by target-induced conformational changes or ratiometric one by coupled "signal-on/off" dual-signaling. 20 Up to now all kinds of DNA structures have been applied to electrochemical experimental study, such as single-strand, 21 double helix, 22 hand-in-hand, 23 sandwich,…”