A Novel Plasmonic Nanoantenna-Based Sensor With Graphene Tuning for Cancer Biomarker Detection

The development of highly sensitive and selective biosensors is crucial for early cancer diagnosis. This study presents a novel plasmonic nanoantenna-based sensor, designed to detect cancer biomarkers in the 1–10-THz range. The Hole V-Fork nanoantenna, fabricated in gold with a symmetrical structure composed of two arms with three segments each, exhibits resonance frequencies at 1.5, 2.6, and 3.8 THz, with a maximum peak absorption of −78 dB. A thorough parametric analysis identified an optimal geometric configuration with a 62.86- $\mu $ m arm length, 30.11- $\mu $ m width, 200-nm thickness, and 60-nm gap, ensuring high directivity and enhanced sensing capabilities. In addition, integrating a 3-nm graphene layer between the gold and silicon substrate introduced tunability, effectively shifting the resonance frequency and improving the sensor’s adaptability. A ${4}\times {4}$ nanoantenna array was designed and simulated, maintaining stable resonance frequencies while enhancing sensitivity and signal strength. Compared to the conventional Bowtie nanoantenna, the Hole V-Fork structure demonstrated superior impedance matching, stronger absorption, and better directivity. Sensitivity analysis using collagen as an analyte revealed a resonance shift corresponding to an average sensitivity of 607 GHz/RIU for the array configuration. The nanoantenna performance was experimentally validated using Fourier transform infrared spectroscopy (FTIR), confirming its potential for detecting minute biomolecule concentrations. Due to its scalability, high sensitivity, and frequency tunability, the Hole V-Fork nanoantenna constitutes a significant advancement in THz plasmonic biosensing. Its ability to detect cancer biomarkers with high precision positions it as a promising candidate for noninvasive, next-generation biomedical diagnostics.