This thesis investigates how different silver-based SERS substrates can improve Raman signal detection for chemical and biological samples. Two fabrication methods, chemical deposition and sputtering, were used to create nanostructured surfaces on silicon wafers. The substrates were tested using Rhodamine 6G to compare sensitivity, signal intensity, and enhancement factors. The results show that the substrate made by chemical deposition provided stronger Raman enhancement than the sputtered one. Both SERS substrates were subsequently evaluated using blood plasma and compared with a pure silicon substrate. The findings indicated that the nanostructured silver surfaces provided superior Raman enhancement relative to pure silicon.