One-step electrochemical aptasensor for lactate detection in athlete training using AuPt NPs and PEI-rGO composite with Na⁺-dependent DNAzyme

This study introduces a novel electrochemical aptasensor designed for the sensitive detection of lactate in athlete sweat. The sensor is based on a PEI-rGO-modified SPCE coupled with AuPt NPs, and utilizes Na⁺-assisted DNAzyme for signal amplification. The PEI-rGO modification enhances the aptasensor's conductivity, while the AuPt NPs efficiently load MB and LDNA, generating stable electrochemical signals. Furthermore, the Na⁺-dependent DNAzyme leverages the Na⁺ naturally present in sweat to activate the cleavage process, amplifying the detection signal. The sensor exhibits a strong linear relationship between current response and lactate concentration in the range of 5 × 10^-3 to 10 mM, with a limit of detection (LOD) of 2.974 μM. It demonstrates excellent specificity, stability, and repeatability. The optimized aptasensor offers significant potential for real-time, non-invasive lactate monitoring, particularly in athletic performance and health assessment. This work provides a promising approach for the development of reliable, portable biosensors for tracking lactate metabolism, with implications for sports science and health management.