Highly Sensitive Electrochemical Biosensor Assembled by Au Nanoparticle/MOF-5 Composite Electrode for DNA Detection

An efficient and sensitive electrochemical method for detecting trace amounts of sequence-specific deoxyribonucleic acid (DNA) by using a gold nanoparticle (Au NP)/metal-organic framework (MOF) composite electrode was developed. An electrochemical DNA sensor was constructed by introducing Au NPs as electrochemical signal labels to an MOF-5-modified glassy carbon electrode as the adsorption background platform. The unique porous structural characteristics of MOF-5 considerably enhanced the electrocatalytic activity of the Au NPs and improved the DNA detection limit of the resultant electrode. The cyclic voltammetry, linear sweep voltammetry, and chronoamperometry results for the electrochemical DNA sensor demonstrated that the electro-oxidation current gradually increased as the target DNA concentration was increased. Target DNA concentrations of 1 pM to 100 nM presented a good linear relationship with current. The calculated detection limit was 0.05 pM. The Au/MOF composite electrode materials presented considerable potential for application in the development of electrochemical biosensors for DNA detection.