2D MoS2 plasmonic nanocavity based SERS platform for bilirubin detection

Although various methods can be used to detect bilirubin at the micromolar level, achieving reliable detection in the sub-nanomolar range remains challenging. Sensitivity at these ultralow levels is vital, as new evidence strongly associates bilirubin with chronic heart, lung, and neurological disorders. This accuracy is also essential for creating diagnostic protocols that can efficiently track bilirubin levels, assisting in managing related conditions. Such advancements will lead to enhanced diagnostic tools and methods, enabling more precise bilirubin monitoring in clinical environments. Here, the aforesaid blind-spot is addressed by utilizing surface enhanced Raman spectroscopy (SERS) as fingerprint technique to detect bilirubin concentrations as low as 0.1 nM. A plasmonically active 2D MoS2 based SERS substrate is formulated and optimized for single step SERS sensing of bilirubin. Plasmonic cavity based approach is utilized to circumvent the problem related to fluorescent background overwhelming the SERS signal. The 2D MoS2 based SERS platform shows threefold enhancement of scattering in comparison to the traditional gold nanoparticle on Si/SiO2 approach. The Raman signature of bilirubin is calibrated by taking citrate as a stable reference analyte and is shown to vary linearly with logarithmic concentration across the picomolar to micromolar range.