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.

Automated summary

An amplified electrochemiluminescence ratiometric biosensor for p53 DNA sequence assay was developed using gold@carbon dots and gold@luminol nanoparticles, along with an enzyme-free DNA walker for signal amplification. The sensor exhibited high sensitivity and accuracy, with a lower limit of 0.34 fM for target detection. The use of Au@luminol and Au@CDs offered cost-effective, biocompatible, and easily labeled advantages, providing a new platform for ratiometric ECL biosensors.