Ultrasensitive surface-enhanced Raman scattering detection of biological pollutants by controlled evaporation on omniphobic substrates

Abstract

A simple and highly sensitive method, combining slippery liquid-infused porous substrates and surface-enhanced Raman spectroscopy (SLIPSERS) was used to detect biological pollutants at very low concentrations. Two commonly used rodenticides (brodifacoum and sodium monofluoroacetate) with long biological half-lives were selected as analytes. The SLIPSERS platform gives reproducible SERS enhancement and this allows "label-free" SERS detection of these environmental pollutants.Analyte ions were detected down to a concentration of 10 À14 M for brodifacoum and 10 À9 M for sodium monofluoroacetate. The limit of detection, limit of quantification and limit of linearity for brodifacoum are 10 À12 M, 10 À10 M and 10 À6 M respectively. The SLIPSERS method uses a physical process to significantly increase analyte concentration, and SERS enhancement and therefore can be generally applied to a range of environmental pollutants. The method can be successfully used for ultra-sensitive detection of several chemical and biological contaminants and meet the emerging needs of environmental monitoring and food safety analysis.

Optical Detection of CoV-SARS-2 Viral Proteins to Sub-Picomolar Concentrations

“…SERS is a very sensitive chemical detection method, allowing quantification of chemical and biological analytes to subpicomolar concentrations. 32,33 It is based upon measuring the Raman spectrum of analytes that coordinate to the surface of nanoparticles or nanostructures, themselves immobilized on a solid support. 34 In particular, the SLIPSERS method, which involves depositing nanoparticles onto a slippery, omniphobic substrate, is an ultrasensitive method that can detect analytes to subfemtomolar concentrations.…”

DeltaPCA: A Statistically Robust Method for Detecting Protein Analyte Binding to Aptamer-Functionalised Nanoparticles using Surface-Enhanced Raman Spectroscopy

“…Surface-enhanced Raman spectroscopy is a promising technique for direct detection of environmental contaminants and/or biomolecular disease markers at extremely low concentrations. [1][2][3][4][5] Advances in surface and substrate engineering have enabled selected analytes to be detected down to femtomolar or even attomolar concentrations, approaching the single-molecule detection limit. [6][7][8] However, the exquisite sensitivity and high spatial resolution of surface-engineered SERS often comes at the cost of reproducibility; substantial fluctuations in a SERS spectrum can be observed as molecules drift into and out of electric-field hot spots, and SERS spectra are very sensitive to differences in sample preparation, optical alignment and variations in laser power.…”

“…The main advantage of SLIPSERS over other surface-enhanced Raman methods is that it dramatically improves sensitivity and decreases detection limits, without requiring sophisticated substrate engineering. 4,6 However, questions of analyte specificity remain, particularly in the context of analysing complex chemical and biochemical mixtures. This can be overcome by nanoparticle surface functionalisation which selectively bind of the analyte of interest and enhance its local surface concentration.…”