Surface-enhanced Raman scattering (SERS) on a gold triangular nanoprisms array with precisely controlled size and spacing, fabricated via electron beam lithography was investigated. This SERS substrate shows reasonable efficiency at 785 nm excitation for the detection of p-mercaptoaniline (pMA), and a remarkable homogeneity of the SERS response over the sensing area. The performances of the engineered SERS substrate with human prostate cancer cells has been tested, highlighting excellent sensitivity in comparison to spontaneous Raman scattering, especially in the 1500-1700 cm-1 frequency range, characteristic of the peptide linkage and the neighboring functional groups. The results are promising for biosensing applications, provided the selectivity is enhanced by suitable functionalization approaches.