A Dual-Aptamer Electrochemical Sensor for Simultaneous Detection of L-Lactate and Prostate-Specific Antigen

Accurate analysis of prostate cancer (PC)-related biomarkers requires sensing platforms capable of sensitive and multiplex detection in complex biological environments. Herein, we propose a signal-on electrochemical aptamer-based sensor (E-AB) for the simultaneous detection of L-lactate (L-Lac) and prostate-specific antigen (PSA). To maximize analytical performance, two Lac aptamer sensing configurations, single-stranded (ssLac201) and double-stranded (dsLac201), were constructed and comparatively evaluated. The dsLac201 structure displayed more effective background suppression and enhanced target induced signal response. Under optimized conditions, the dsLac201-based sensor exhibited a wide linear range from 500 nM to 10 mM for L-Lac, with a low detection limit of 157 nM and high selectivity. Based on this optimized design, a dual-aptamer electrochemical platform was further engineered through programmable nucleic acid assembly, enabling simultaneous detection of L-Lac and PSA via dual-input signal integration. The dual-target sensor showed broad analytical ranges for both biomarkers (L-Lac: 500 nM–10 mM; PSA: 10 pg mL−1–500 ng mL−1) and retained promising performance in serum samples. This work demonstrates a simple and versatile strategy for multiplex electrochemical biosensing and provides a promising platform for PC-related biomarker monitoring and clinical biomedical analysis.