Ultrasensitive Sandwich-Type Electrochemical Aptasensor for Dual Detection of Lung Cancer Biomarkers

The fabrication and signal amplification play important roles in electrochemical biosensors to achieve high sensitivity and low cost. In this study, a sandwich-type electrochemical aptasensor for dual lung cancer biomarkers, neuron-specific enolase (NSE) and epidermal growth factor receptor (EGFR), was constructed based on black phosphorus–gold nanocomposites (BP–AuNCs) and aptamers. BP–AuNCs nanocomposites were synthesized by an in situ reduction process without any reducing agent and decorated on the surface of the detachable spherical working electrodes (WEs). The signal amplification was obtained by the good electrical conductivity of BP–AuNCs, as well as the large number of binding sites provided for the capture aptamers (Apt 1). Moreover, the addition of secondary aptamers (Apt 2) formed the sandwich-type aptasensor to obtain a dual signal amplification. The resulting signal by the differential pulse voltammetry (DPV) analysis in the solution containing ferroferricyanide redox probe (Fe(CN)
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is proportional to the concentration of the target biomarkers. The electrochemical aptasensor platform was simply fabricated on the cloth substrate by screen printing. Under the optimized conditions, the proposed aptasensor was used in the simultaneous detection of two lung cancer biomarkers, NSE and EGFR. Good linear detection was obtained in a range of 1–400 ng/mL (NSE) and 1–600 ng/mL (EGFR) with ultralow detection limits of 0.1 ng/mL (NSE) and 0.6 ng/mL (EGFR), respectively. Experimental results display good selectivity, stability, and accuracy, thus providing a promising low-cost platform in the preliminary estimates and diagnosis of lung cancer at early stages.