A terahertz metamaterial biosensor using nanocrystals for noninvasive urine bilirubin diagnosis.

The accurate and non-invasive detection of bilirubin in urine is crucial for medical diagnostics. Traditional methods often face challenges such as invasiveness, complexity, and the requirement for specialized equipment. In this study, we propose a tunable plasmonic metamaterial sensor enhanced with nanocrystals for terahertz (THz) wave engineering, enabling direct, non-invasive estimation of bilirubin concentrations in urine. Computational electromagnetic simulations reveal an operating wavelength of 952 nm, a sensitivity (SS) of 325 nm/RIU, a figure of merit (FoM) of 65, a quality factor (Q) of 366.75, and an electric field intensity enhancement (EFIE) of 1714. These results demonstrate the sensor's high performance and indicate its optimal efficiency point. Compared with conventional approaches, the proposed device provides higher detection sensitivity and sharper resonance, highlighting its potential as an efficient and non-invasive tool for bilirubin monitoring in urine.