Rapid electrochemical dual-target biosensor composed of an Aptamer/MXene hybrid on Au microgap electrodes for cytokines detection

Rapid detection methods for cytokine storm markers, such as tumor necrosis factor α (TNF-α) and interferon gamma (IFN-γ), are required. Herein, we describe the fabrication of a rapid electrochemical dual-target biosensor composed of aptamer/MXene (Ti3C2) nanosheet on an Au microgap electrode. Alternating current electrothermal flow (ACEF) significantly reduced the detection time (<10 min) to achieve the rapid biosensor construction. Additionally, MXene nanosheet was synthesized to improve the detection sensitivity. A dual-type Au microgap electrode was designed to measure TNF-α and IFN-γ levels using a single biosensor. Moreover, it performs 12 measurements using a small sample volume. To reduce detection time with stable aptamer-target complex formation, various ACEF conditions were evaluated and optimized to 10 min. Using the optimal conditions, the limit of detection (LOD) and selectivity were determined by electrochemical impedance spectroscopy (EIS). A linear region was observed in the concentration range of 1 pg/mL to 10 ng/mL of TNF-α and IFN-γ. The LOD of TNF-α and IFN-γ were 0.15 pg/mL and 0.12 pg/mL within 10 min, respectively. Furthermore, the proposed biosensor detected TNF-α and IFN-γ diluted in 10% human serum in the concentration range of 1 pg/mL to 10 ng/mL with LODs of 0.25 pg/mL and 0.26 pg/mL, respectively.