Electrochemical competitive detection of CYFRA 21-1 on a gold nanoparticles/graphene oxide/MoO3-MoS2 bioelectrode employing hydroquinone/gold nanotags.

Lung cancer is one of the deadliest forms of cancer, with a significantly high mortality rate. Consequently, early diagnosis is crucial for effective treatment and improved survival outcomes. The cytokeratin 19 fragment, CYFRA 21-1, is a key biomarker for lung cancer detection and is strongly associated with non-small cell lung cancer, particularly squamous cell carcinoma. Accordingly, establishing a sensitive and reliable method for early lung cancer diagnosis based on CYFRA 21-1 detection is critical to improving clinical outcomes. This study introduces a new highly sensitive competitive electrochemical platform capable of detecting CYFRA 21-1using gold nanoparticles (AuNPs)/graphene oxide (GO)/MoO3-MoS2 nanocomposite and gold (Au) nanotags. The sensing platform is constructed by depositing CYFRA 21-1 on a AuNPs/GO/MoO3-MoS2 nanocomposite-modified screen-printed electrode (SPE). In the detection process, the electrode specifically captures unbound anti-CYFRA 21-1 on hydroquinone (HQ)@Au nanotags after competitive binding to the target CYFRA 21-1 in the sample. Our strategy for signal amplification uses the electrochemical response of HQ, anchored to nanotags, as a redox probe. The combination of three nanomaterials enhances electrode reactivity by increasing surface area and conductivity, while maintaining sufficient CYFRA 21-1 bioactivity due to the materials' biocompatibility. Quantitative analysis is achieved by the signal-off HQ peak current, which is inversely proportional to CYFRA 21-1 concentration, with two linear ranges of 0.010-5.0 and 5.0-25 ng mL-1 on a logarithmic concentration scale and a detection limit of 3.0 pg mL-1. Moreover, the sensor exhibits high specificity, reliable reproducibility, and exceptional stability. Simultaneously, the proposed competitive immunosensor can effectively detect CYFRA 21-1 in human serum samples, demonstrating good recovery. The implementation of this electrochemical biosensor offers an opportunity to develop an accurate, cost-effective, and user-friendly diagnostic tool for detecting this type of cancer.