Amplified electrochemical determination of UO 2 2+ based on the cleavage of the DNAzyme and DNA-modified gold nanoparticle network structure

A superior electrochemical biosensor was designed for the determination of UO in aqueous solution by integration of DNAzyme and DNA-modified gold nanoparticle (DNA-AuNP) network structure. Key features of this method include UO inducing the cleavage of the DNAzyme and signal amplification of DNA-AuNP network structure. In this electrochemical method, the DNA-AuNP network structure can be effectively modified on the surface of gold electrode and then employed as an ideal signal amplification unit to generate amplified electrochemical response by inserting a large amount of electrochemically active indicator methylene blue (MB). In the presence of UO , the specific sites on DNA-AuNP network structure can be cleaved by UO , releasing the DNA-AuNP network structure with detectable reduction of electrochemical response intensity. The electrochemical response intensity is related to the concentration of UO . The logarithm of electrochemical response intensity and UO concentration showed a wide linear range of 10~100 pM, and the detection limit reached 8.1 pM (S/N = 3). This method is successfully used for determination of UO in water samples. Graphical abstract Fabricated DNAzyme network structure for enhanced electrical signal. Numerical experiments show that the current signal decreases as the concentration of UO increases. It can be seen that the biosensors could be used to detect UO in aqueous solution effectively.