Nanospray-assisted deposition of silver nanoparticles for mapping of a peptide in nanofibrous layers via surface-enhanced Raman spectrometry

Surface-enhanced Raman spectrometry (SERS) is a universal detection tool identifying molecules via vibrations of their chemical bonds. Its function requires the close localization of metal nanostructures and the analyte. In this work, we present a lab-made instrumentation for the deposition of silver nanoparticles on a strongly hy-drophilic nanofibrous composite via a nanospray for SERS mapping of an incorporated peptide. The nanospray-sample distance was revealed as the most crucial parameter since it directly influences the moisture of the deposited colloid. Residual water was recognized as a sensitivity enhancer. Additionally, we continuously introduced a solution of sodium chloride to the colloid increasing its ionic strength, which formed a more ho-mogeneous profile of the deposit. After the deposition process, the treated sample was scanned via a SERS laser and the collected Raman spectra were transformed into a distribution map of the peptide at a concentration of 5 mu g/g.

Automated summary

In this study, silver nanoparticles were deposited on a highly hydrophilic nanofibrous composite using a nano spray for surface-enhanced Raman spectroscopy (SERS) mapping of a peptide-incorporated material. The distance between the nano spray and the sample was found to be the most crucial parameter, as it directly affected the moisture content of the deposited colloid. Residual water was identified as a sensitivity enhancer. Additionally, the addition of a sodium chloride solution to the colloid increased its ionic strength, leading to a more homogeneous profile of the deposit. After the deposition process, the treated sample was scanned using a SERS laser, and the collected Raman spectra were transformed into a distribution map of the peptide at a concentration of 5 mu g/g.