Terahertz anti-resonance hollow-core fiber for label-free and nondestructive detection of circulating tumor cells

Circulating tumor cells (CTCs) can be used as important biomarkers to reflect the progress and malignancy of tumors. However, current CTC detection technologies have some limitations for clinical applications due to their complexity, low specificity and high cost. Herein, we develop a terahertz anti-resonance hollow core fiber (THz AR-HCF) biosensor for CTC detection. Through simulation and experiment comparisons, the low-loss property of the THz AR-HCF is verified, and a suitable fiber is selected for biosensing applications. By measuring different cell numbers and different types of cancer cells, a good linear relationship between THz transmittance and the numbers of cells between 10 and 106 was found. Meanwhile, different types of tumor cells can be distinguished by comparing THz transmission spectra, indicating that the biosensor has high sensitivity and specificity for CTC detection. The biosensor only required a small amount of sample, as low as 100 μl, and enables label-free and nondestructive quantitative detection. Flow cytometry results showed that the cell viability was as high as 98.5±0.26% after whole assay process and there was no statistically significant difference compared with the negative control. This study demonstrated that the proposed THz AR-HCF has great potential for highly sensitive, label-free and nondestructive detection of CTCs in clinical samples.