Implantable antenna immunosensor based on Au-decorated graphene film for wireless CEA detection

Early diagnosis of cancer is crucial for treatment and recovery. Carcinoembryonic antigen (CEA), as an important tumor marker, its traditional detection methods rely on costly instruments, leading to increased expenses and usage limitations. This paper proposes a miniature implantable antenna immunosensor for real-time monitoring of CEA. The antenna immunosensor works as both a radiator and a sensor. The radiation patch adopts a double symmetric bending structure, greatly reducing the overall volume of the antenna (5×3×0.127 mm3). Although small in size, the peak gain of the antenna is -18.2 dB, indicating that the antenna has good radiation characteristics. In addition, Au-nanoparticles-decorated graphene film was deposited on the radiation patch and worked as sensitive film, which enabled the antenna to have good sensing characteristics. The immunosensor demonstrated a sensitivity of 2.46 MHz/log (ng/mL) across an antigen concentration range from 0.01 ng mL-1 to 100 ng mL-1. A comprehensive analysis of the immunosensor's performance revealed commendable reproducibility, long-term stability, specificity, and continuous monitoring ability. Furthermore, tests conducted on actual human serum indicated a recovery range between 93.5% and 100.2%. These results prove that the antenna immunosensor has great application prospects in home tumor detection.