Detection of 4′,6-diamidino-2-phenylindole within silver-doped silica sol- and aerogels using surface-enhanced Raman spectroscopy

• Acid catalyzed silica sol- and aerogels containing Ag NP were examined as SERS substrates.
• Silica sol-gels stabilized Ag NP in the presence of a cationic dye, DAPI, versus solution.
• Stable SERS spectra were obtained on silica sol-gels containing Ag NP and DAPI.
• SERS spectra on silica aerogels indicated retention of Ag NP, but hydrolysis DAPI.

Silver nanoparticle doped silica sol-gels and aerogels were investigated as possible substrates for the surface-enhanced Raman scattering (SERS) based detection of small molecules. The target molecule chosen for this study was 4′,6-diamidino-2-phenylindole (DAPI), a fluorescent organic dye known to bind to DNA. Sol-gels were prepared by the acid-catalyzed hydrolysis of tetramethyl orthosilicate (TMOS) in the presence of DAPI and colloidal silver. Aerogels were prepared via carbon dioxide supercritical fluid drying of the sol-gels. SERS measurements of the sol- and aerogels were obtained following synthesis, and suggest that the materials tested are viable substrates for the SERS detection of DAPI.