A dual-potential ratiometric electrochemiluminescence biosensor based on Au@CDs nanoflowers, Au@luminol nanoparticles and an enzyme-free DNA nanomachine for ultrasensitive p53 DNA detection

Herein, an amplified electrochemiluminescence (ECL) ratiometric biosensor for p53 DNA sequence assay was described based on gold@carbon dots nanoflowers (Au@CDs), gold@luminol nanoparticles (Au@luminol) as luminophors and an enzyme-free DNA walker for signal amplification. The ratiometric strategy endowed the sensor with a prominent accuracy. Taking advantage of DNA-walker signal amplification feature, a high sensitivity for target detection was achieved. Under the optimal conditions, the designed biosensor exhibited a lower limit of 0.34 fM and wide linear range from 1 fM to 10 pM for p53 DNA sequence detection. In particular, compared with traditional Ru(bpy)(3)(3+)/Ru(bpy)(3)(2+) derivatives and semiconductor nanoparticles, Au@luminol and Au@CDs have the advantages of cost-effective, excellent biocompatibility, and easy labeling, which offered new opportunity for building ratiometric ECL biosensor platform.