Terahertz Biosensor for Specific Detection of Alpha-Fetoprotein in Hepatocellular Carcinoma Patients

Alpha-fetoprotein (AFP) is closely associated with the occurrence and development of hepatocellular carcinoma (HCC). However, for many HCC patients at early stage, the AFP concentration is very low and difficult to test. Herein, a terahertz (THz) metamaterials (MMs) biosensor modified with AFP antibody (ATB-AFP) and aptamer (APT-AFP) polymer probe was proposed to detect trace AFP. The biosensor has a theoretical sensitivity of 124 GHz/refractive index unit (RIU), and its experimental limit of detection (LOD) is 0.1 ng/mL. When it is modified with AuPEG2000-ATB-AFP and AuPEG2000-APT-AFP, its sensitivity for AFP antigen in HCC serum is 17.74 and 15.89 GHz/lg(ng/mL), respectively. The proposed biosensor could detect trace biomarkers at the molecular level, which is significant for the diagnosis of the HCC and many other cancers at early stage.