Fabrication of SERS-sensitive nanopipette with silver nanoparticles obtained by vacuum thermal evaporation

This work is concerned with developing an approach to producing an array of plasmonic Ag nanoparticles on the nanopipette surface. The vacuum thermal evaporation method followed by annealing was used to form the nanoparticle array. The surface morphology of the modified pipettes was investigated by scanning electron microscopy. Based on the SEM images obtained, the most efficient method for particle deposition on the pipette was selected. It was found that two-stage depositions on the horizontally mounted pipette formed an array of silver nanoparticles with a size of about 16 nm. The obtained modified nanopipettes were investigated by Raman spectroscopy. A laser with a wavelength of 532 nm was used to obtain the spectra. Rhodamine in the R6G modification was used as an analytical substance. The enhance factor of the modified pipette was calculated by comparing it with pure glass at the same power values of the laser and concentration of the analytical substance, rhodamine R6G. The developed approach to modifying the surface of nanopipettes allows fabricating SERS pipettes for monitoring various intracellular biomarkers.