Martynas Velicka, Milda Pucetaite, Justinas Ceponkus and Valdas Sablinskas
Vilnius University, Giedros str. 33, Vilnius, Lithuania
Surface-enhanced Raman scattering (SERS) spectroscopy has been increasingly proposed as a method of choice for disease diagnosis and prevention. Advantages of SERS over conventional Raman spectroscopy includes significantly increased signal which allows detection of trace amounts of substances in the sample and fluorescence quenching. On the other hand, if SERS spectroscopy is going to be used in routine analysis several problems, such as reproducibility of the enhancement factor, should be considered. In addition, suitable SERS substrates should be selected according to the sample and available experimental conditions. The aim of this work is to test the suitability of various SERS substrates for detection of uric acid traces in biological fluids.
Several colloidal solutions of Ag spheres, Ag prisms, Au rods and Au branched nanoparticles in different sizes and concentrations were prepared. In order to form a substrate, a drop of the colloid was placed on a silver plated microscope glass slide and dried. In addition, substrates of Au nanodendrites on graphite plates were produced.
It was found that concentrations of uric acid in biological liquids as low as 10-5-10-7 M can be detected only using substrates produced from concentrated Ag prism colloid, while the other substrates give lower enhancement factor of Raman signal.
Keywords: SERS; Uric acid; silver colloids; biological fluids.