A folate receptor electrochemical sensor based on terminal protection and supersandwich DNAzyme amplification

Based on the protecting effect of folate receptor (FR) toward folic acid (FA) modified DNA and the signal amplification of supersandwich DNA structure, we designed an interesting electrochemical biosensor for FR. In the present system, with the increase of FR, protecting more FA bound DNA from hydrolysis by exonuclease I (Exo I), FA bound DNA will hybridize to form more supersandwich DNA structure resulting in an increased electrochemical signal. A relationship between the concentration of the target protein, FR, and the obtained electrochemical signal can be established. The signal was obtained by the catalysis on H2O2 in the system containing Fc and hemin/DNAzyme. The detection concentration range of FR was from 1.0to 20.0 ng/mL with an achieved detection limit of 0.3 ng/mL which approached clinically relevant concentrationsof FR.

► An interesting electrochemical biosensor for folate receptor (FR) was designed.
► The protecting effect of FR toward folic acid (FA) modified DNA was used in the system.
► The supersandwich DNA structure was used for the signal amplification.
► The approach showed high sensitivity and low detection limits.