Enhanced terahertz metasurface biosensor with reduced substrate effect for trace detection of lung cancer cells

This paper reports an ultrasensitive Terahertz metasurface biosensor with the reduced substrate effect for trace detection of lung cancer cells. By innovatively etching the quartz substrate before gold deposition, our design achieves enhanced light-matter interaction, achieving trace detection of lung cancer cells. The biosensor demonstrates dual-parameter detection capability through both resonant frequency shifts (Δf) and amplitude attenuation (ΔA). Experimental results reveal distinct responses to living HCC-827 cancer cells at ultralow concentrations: Δf values of 46 GHz (pure serum), 52 GHz (1 cell/Unit), 62 GHz (2 cells/Unit), and 66 GHz (3 cells/Unit), with ΔA values of 12.22, 12.62, 14.17, and 14.76 dB, respectively. Crucially, the biosensor reliably detects 1 cell/Unit (69 cells/mm²) with 6 GHz Δf and 0.4 dB ΔA differentials vs control, surpassing current THz-TDS resolution limits. This technology shows significant potential for cost-effective early lung cancer diagnosis through rapid, label-free cell detection.