Cancer Biomarkers Ultrasensitive Detection Based on Terahertz Frequency-Comb-Like

Abstract

Terahertz (THz) biosensors provide a new avenue for the early diagnosis and treatment of cancers. However, conventional THz biosensors cannot achieve high sensitivity due to limited absorption peaks. In this work, we propose a cancer biomarker ultrasensitive detection method based on THz frequency-comb-like. At first, we design a basic biosensor which has three resonant absorption peaks. Then, we proportionally change the size of basic biosensor and obtain other 4 biosensors with different resonant absorption peaks. Finally, a frequency-comb-like containing 8 uniformly spaced absorption peaks in the range of 0.5 - 1.3 THz is realized by appropriately selecting the absorption peaks of these 5 biosensors. Three cancer biomarkers of carcinoembryonic antigen (CEA), neuron-specific enolase (NSE) and squamous cell carcinoma (SCC) are used as samples of experiment. Under the same concentration, the frequency shifts generated by each peak are accumulated. For samples from 0.1 pg/mL to 50 ng/mL, the cumulative frequency shifts are 122-547 GHz, 168-815 GHz, and 142-505 GHz, respectively. The sensitivity (Sc) of concentration are 64.995 log(ng/ml), 105.005 log(ng/ml), and 62.634 log(ng/ml), respectively. The limit-of-detection (LOD) is 0.1 pg/mL. Compared with other methods using single or few resonant absorption peaks, this method shows higher sensitivity and lower LOD. Therefore, it is valuable for trace molecule detection, biomedical sensing and cancer diagnosis at early stage.