Reagentless aptamer based on the ultrasensitive and fast response electrochemical capacitive biosensor for EGFR...

Non-small cell lung cancer (NSCLC) is still the leading cause of lung cancer-related deaths globally, affecting both men and women. Mutations in the epidermal growth factor receptor (EGFR) are most common among patients with NSCLC, especially Asian patients. Here, we introduce an electrochemical capacitive biosensor for the early detection of NSCLC through specific identification of EGFR. A novel and reagentless EGFR aptamer was designed using the systematic evolution of ligands by exponential enrichment (SELEX) process and immobilized on a chromium (Cr)/gold (Au) electrode, with capacitance signals used for detection. The biosensor employs an interdigitated capacitor electrode (IDCE) functionalized with 3-mercaptopropionic acid (MPA), enhancing EGFR aptamer immobilization, while 6-mercapto-1-hexanol (MCH) was used for effective blocking to ensure robust and high-affinity binding to target analytes. The IDCE capacitive biosensor achieved real-time rapid detection within 3 s and demonstrated a detection limit of 0.005 ng/mL for the EGFR peptide, with a dynamic range of 10^-11-10^-7 ng/mL. Furthermore, the specific EGFR aptamer-immobilized IDCE biosensor was found to be regenerable and reusable up to five times using deionized water. This biosensor offers a rapid, label-free, and highly selective approach for early-stage EGFR detection in NSCLC. Its portability and scalability make it a promising tool for point-of-care diagnostic applications in biomedicine, potentially advancing the field of cancer diagnostics.