Surface enhanced Raman spectroscopy of l-alanyl-l-tryptophan dipeptide adsorbed on Si substrate decorated with triangular silver nanoplates

•The triangular silver nanoparticles decorated SERS substrates were prepared by direct silver ions reduction on silicon wafers.•The SERS measurements of Ala-Trp dipeptide were carried out in liquid.•The different orientation of Ala-Trp dipeptide on nanostructured silver surface was proposed.

Raman and surface enhanced Raman spectroscopies have been used to investigate interaction of l-alanyl-l-tryptophan (Ala-Trp) dipeptide with nanostructured silver surface. A highly sensitive surface enhanced Raman scattering (SERS)-based biosensor has been employed for label-free dipeptide detection and its orientation on the nanostructured surface. The synthesis of SERS substrate was based on direct silver ions reduction on hydrofluoric acid etched silicon wafer. Raman and SERS spectra of Ala-Trp were recorded in liquid to keep native environment for dipeptide. To the best of our knowledge, this work is a first attempt to analyze the structure of Ala-Trp dipeptide by Raman spectroscopy.

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