Ultrasensitive SERS-Based Plasmonic Sensor with Analyte Enrichment System Produced by Direct Laser Writing

Abstract

We report an easy-to-implement device for SERS-based detection of various analytes dissolved in water droplets at trace concentrations. The device combines an analyte-enrichment system and SERS-active sensor site, both produced via inexpensive and high-performance direct fs-laser printing. Fabricated on a surface of water-repellent polytetrafluoroethylene substrate as an arrangement of micropillars, the analyte-enrichment system supports evaporating water droplet in the Cassie-Baxter superhydrophobic state, thus ensuring delivery of the dissolved analyte molecules towards the hydrophilic SERS-active site. The efficient pre-concentration of the analyte onto the sensor site based on densely-arranged spiky plasmonic nanotextures results in its subsequent label-free identification by means of SERS spectroscopy. Using the proposed device, we demonstrate reliable SERS-based fingerprinting of various analytes, including common organic dyes and medical drugs at ppb concentrations. The proposed device is believed to find applications in various areas, including label-free environmental monitoring, medical diagnostics, and forensics.

FRET Pumping of Rhodamine-Based Probe in Light-Harvesting Nanoparticles for Highly Sensitive Detection of Cu2+

“…The Fourier transform infrared radiation (FT-IR) spectra of the compounds in the range 400-4000 cm -1 were recorded using a Perkin Elmer Spectrum 100BX II spectrometer in KBr pellets. 1 H, 13 C NMR spectra were performed on a Bruker Avance 400 with the frequency of proton resonance 400 MHz using CDCl 3 as the solvent and tetramethylsiliane as the internal reference. UV-VIS and fluorescence measurements were performed on Shimadzu UV-2600 spectrophotometer and Shimadzu RF-6000 spectrofluorophotometer using 1 cm path length cuvettes at room temperature.…”

“…Of course, fluorescence measurements are more accurate than colorimetric, but they do not provide a significant increase in sensitivity, since they have exactly the same fundamental limitations. Modern approaches for ultrasensitive chemical sensing on the basis of surface-enhanced Raman scattering [11][12][13][14] or surface-enhanced fluorescence [15][16][17][18], allow determination of significantly lower analyte concentrations, but require powerful and expensive experimental equipment, both for measurements and for fabrication of nanostructured enhancing substrates.…”