Functionalized MoS 2 : circular economy SERS substrate for label-free detection of bilirubin in clinical diagnosis.

A one-pot hydrothermal synthesis of Fe-doped MoS 2 nanoflowers (Fe-MoS 2 NFs) has been developed as a surface-enhanced Raman spectroscopy (SERS) substrate. The Fe-MoS 2 NFs display high reproducibility, stability, and recyclability, which is beneficial for the development of the sustainable ecological environment. The SERS substrate provides a high enhancement factor of 10 5 , which can be ascribed to the inducing defects by doping Fe that can improve the charge transfer between probe molecules and MoS 2 . The Fe-MoS 2 NFs have been used to detect bilirubin in serum. The Fe-MoS 2 NF SERS substrate exhibits a linear detection range from 10 -3 to 10 -9  M with a low limit of detection (LOD) of 10 -8  M. The substrate displays an excellent selectivity to bilirubin in the presence of other potentially interfering molecules (dextrose and phosphate). These results provide a novel concept to synthesize ultra-sensitive SERS substrates and open up a wide range of possibilities for new applications of MoS 2 in clinical diagnosis.