SERS platform for detection of lipids and disease markers prepared using modification of plasmonic-active gold gratings by lipophilic moieties

New functional SERS platform for effective detection of lipophilic disease markers was proposed and realized. The work was aimed at the achievement of highly-reproducible SERS results obtained in shorter measuring times. The homogeneous plasmon distribution was achieved through the introduction of large area surface plasmon-polariton supported substrate with a good smearing of plasmon intensity along the working substrate area. Homogeneous distribution of targeted lipophilic molecules on the SERS surface was realized through the surface grafting with alkylaryl moieties of various carbon chain lengths via diazonium chemistry. The process of modification was followed and confirmed by XPS and Raman methods. The functionality of created SERS substrates was studied by the contact angle measurement and CVA methods. The possibility of detection of two biomedically significant molecules (squalene and β-sitosterol) was examined. Dependence of the SERS results on the aliphatic chain lengths was tested in the terms of targeted molecules SERS intensity and reproducibility. The prepared SERS substrates were found to be suitable for sensing of squalene and β-sitosterol at the biorelevant μM concentration level.