A fluorescence electrochemical impedance microscopy biosensor based on monolayer WS2 for label-free detection of cancer biomarkers in clinical serum.

Serological detection of lung cancer biomarkers is critical for early diagnosis. However, existing technologies often lack the sensitivity required for clinical applications. Here, we report a fluorescence electrochemical impedance microscopy (F-EIM), a biosensor based on monolayer WS2, which is a label-free imaging technique that provides an ultrasensitive platform for detecting lung cancer biomarkers in complex clinical serum samples of patients. This unique approach enables optical imaging of the local surface charge distribution of atomically thin materials. As a proof of concept, leveraging the charge-sensitive fluorescence of monolayer WS2, the F-EIM biosensor successfully detects small-cell lung cancer biomarkers, including carcinoembryonic antigen (CEA), progastrin-releasing peptide (ProGRP), and neuron-specific enolase (NSE), with limits of detection of 2.16-7.04 ✕10-16 mg/mL. Clinical serological tests with 30 clinical samples confirmed the platform's high sensitivity and specificity. This rapid, highly sensitive, and accurate F-EIM biosensor holds significant promise as a point-of-care diagnostic tool, offering a practical solution to current challenges in cancer detection.