Silver Nanoparticles-Based Substrate for Blood Serum Analysis under 785 nm Laser Excitation

Individuals who have different diseases need a routine assessment of their body metabolism, and the methods that used are practically difficult, inconvenient or expensive. The objective of this study was to develop a technique of human blood serum analysis that is simple, reliable and fast, and based on a surface-enhanced Raman spectroscopy (SERS). In this study, serum samples were examined using conventional Raman (CR) and SERS. The observed CR and SERS bands were analyzed. Several of these bands (724, 813, 890, 961, and 1132 cm−1) clearly stand out by the impact of the SERS technique, as the intensities of these bands in CR measurements are weaker than the intensity of the autofluorescence and noise. The Enhancement Factor (EF) was up to 4 × 105. Stability of the proposed SERS technique was confirmed by the measurements of signal standard deviation. The observed standard deviation does not exceed 19% for different SERS substrates and does not exceed 8% in case of a single SERS substrate measurements. The obtained results demonstrate that the proposed SERS technique is stable and has significant potential in clinical diagnosis applications.