A sandwiched electroanalysis method for probing Anthrax DNAs based on glucose-induced gold growth and catalytic coupling of tyramine using gold-mineralized glucose oxidase

Gold-doped glucoseoxidase (GOx) was fabricated via biomineralization for the electroanalysis of Anthrax DNAs by the catalytic linking of tyramine-labelled DNA probes and gold growth. [Display omitted] •Glucose oxidase (GOx) is remolded by in-site gold biomineralization yielding GOx-Gold.•GOx-Gold shows the double catalysis activities of GOx and peroxidase-like gold catalysis.•GOx-Gold and tyramine linker are employed separately as the labels of DNA probes.•The catalytic linking of tyramine-labelled DNA probes and gold growth is involved.•The electroanalysis strategy enables the DNA detection and base-mutation discrimination. Gold nanoparticles was doped into the protein matrix of glucose oxidase (GOx) by the in-site biomineralization route, yielding the GOx with mineralized gold (GOx-Gold) showing the double catalysis activities of GOx and peroxidase-like gold catalysis. A magnetic separation-based detection method was thus tailored for the sandwiched electroanalysis of Anthrax DNAs using GOx-Gold and tyramine linker as the probe labels. After the DNA hybridization reactions, the tyramine-mediated linking of DNA capture and detection probes was conducted through gold-catalytic oxidization of tyramines labelled at the probe terminuses, followed by the glucose-triggered gold growth catalyzed by GOx. Highly amplified electrochemical output of gold signals was thus achieved toward the ultrasensitive detection of DNAs in blood, with the detection limit down to ∼0.10 fM. Also, the discrimination of DNAs with single-base mutation could be expected. Importantly, such a biomimic gold mineralization route can be tailored for remolding various enzymes with improved intrinsic catalysis and electrocatalysis, thus promising the wide applications in the catalysis, biosensing, and biomedical fields.