Dual electrochemical approaches for rapid gonorrhea DNA diagnosis

Gonorrhea, caused by Neisseria gonorrhoeae, requires rapid diagnostics, especially with the post-pandemic surge in cases. Traditional PCR methods need specialized equipment and trained personnel, underscoring the need for alternative tools. Electrochemical biosensors offer a sensitive, portable solution but have limited reporting for gonorrhea detection. This study develops two electrochemical methods: label-free (signal-off) and labeling (signal-on). The label-free approach uses two DNA sequences and the [Fe(CN)₆]^3-/^4- (potassium ferricyanide/ferrocyanide) redox indicator. The labeling method employs a molecularly amplified DNA sandwich assay with ferrocene-labeled helpers for signal amplification. The label-free method achieved a limit of detection (LOD) of 2.1 nM and a linear dynamic range (LDR) of 10–500 nM, while the labeling method showed an LOD of 4.8 pM and an LDR of 0.5–1000 nM. To enhance practicality, Near Field Communication (NFC)-enabled sensing was used during non-invasive urine sample testing, enabling real-time, wireless detection without sophisticated instruments. This confirmed the superior performance of the labeling method. Molecular dynamics simulations provided insights into structural dynamics, linking experimental data with computational models. This integrated approach highlights the importance of selecting methods based on sensitivity, cost, and ease of use, advancing gonorrhea DNA biosensing technologies.