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 plas- monic 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 THz, 2.6 THz, and 3.8 THz, with a maximum peak absorption of -78 dB. A thorough parametric anal- ysis identified an optimal geometric configuration with a 62.86 μm arm length, 30.11 μm width, 200 nm thickness, and 60 nm gap, ensuring high directivity and enhanced sensing capabilities. Additionally, 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 4x4 nanoantenna array was designed and simulated, maintaining stable resonance frequencies while enhancing sensitivity and signal strength. Compared to the conventional Bowtie nanoan- tenna, 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 non-invasive, next-generation biomedical diagnostics.