Recent progress and challenges in biosensing of carcinoembryonic antigen

Carcinoembryonic antigen (CEA) is a multifunctional glycoprotein that belongs to the immunoglobulin superfamily and plays dual regulatory roles in cancer and fetal development. Due to its crucial biological functions in cancer regulation, CEA levels elevate abnormally in colorectal, breast, lung, gastric, medullary thyroid, and pancreatic cancers. Furthermore, conditions unrelated to neoplasms, such as ulcerative pancreatitis, chronic obstructive pulmonary disease (COPD), cirrhosis, colitis, hypothyroidism, Crohn's disease, and smoking are associated with increased CEA levels. Therefore, developing precise and sensitive strategies for monitoring CEA holds significant importance. This study emphasizes the successful creating of detection methods through surface modification, bio-functionalization, and nano-fabrication to enable effective detection of CEA at trace levels (with a threshold of 20 ng mL⁻¹). It explores various optical and electrochemical (EC) sensors, including electrochemiluminescence (ECL), fluorometric, surface-enhanced Raman scattering (SERS), photoelectrochemical (PEC), and colorimetric methods. The study highlights the integrating of innovative nanomaterials with a range of bioreceptor elements, including peptides, aptamers (Apt), DNA, enzymes, and antibodies (Abs), to enhance the effectiveness of CEA tracking and quantification, which are essential for analytical methods. Additionally, the research identifies gaps, challenges, and areas for improvement in CEA biosensing methods, research, and technology. This review represents an unprecedented assessment of CEA tracking through the application of biosensor technology.