SERS-based technique for accessible and rapid diagnosis of multiple myeloma in blood serum analysis

Surface-enhanced Raman spectroscopy (SERS) is a promising analytical method for studying the structure and composition of multi-component media in clinical practice. However, the practical application of SERS imposes several conditions and restrictions depending on the required analytical accuracy and implementation complexity. This paper proposes a simple serum SERS technique for diagnosing multiple myeloma (MM). The process utilises a substrate composed of agglomerated spherical silver particles (~200 nm) with a capillary effect on sodium nitrate crystals (0.02% volume concentration), excited at a wavelength of 785 nm. Spectral characteristics were recorded using a detector without external cooling, ensuring a cost-effective approach. The proposed low-cost approach was tested on 31 samples from MM and 102 serum samples from an age-matched control group. Combining the SERS technique with the multivariate analysis for serum testing provided high discrimination rates for MM patients compared to the control patients, with an average accuracy of over 96%. Biochemical interpretation of the recorded spectra identified the informative bands at 635 cm-1, 723 cm-1, and 1052 cm-1. Overall, the proposed SERS-based tool can become the basis for screening for MM and can be easily integrated into clinical practice, expanding diagnostic capabilities where expensive laboratory techniques are not affordable.