DNA Structure Transition-Induced Affinity Switch for Biosensing Based on the Strong Electrochemiluminescence Platform from Organic Microcrystals.

Here we described an effective recognition strategy using the target-triggered DNA structure transition as an affinity switch for nucleic acid detection based on the strong electrochemiluminescence (ECL) platform of 9,10-diphenylanthracene (DPA) doped perylene (Pe) microcrystals (DPA@Pe MCs). Specifically, the target-triggered rolling-circle amplification (RCA) could generate a long, single-stranded DNA with repeated G-quadruplex units, which would hinder the access of quenching probes due to the steric hindrance effects offered by the DNA structure transition. Using this effective recognition strategy, an ECL biosensor with ultrasensitive and accurate characteristics was proposed to detect microRNA-21, which showed an excellent linear response from 10 aM to 1 pM with the detection limit down to 4.14 aM. The DNA structure transition-induced affinity switch strategy offered a potential applications in clinical diagnosis analysis.