Electrically Controlled Enrichment of Analyte for Ultrasensitive SERS-Based Plasmonic Sensors

Recently, sensors using surface-enhanced Raman scattering (SERS) detectors combined with superhydrophobic/superhydrophilic analyte concentration systems showed the ability to reach detection limits below the femto-molar level. However, a further increase in the sensitivity of these sensors is limited by the impossibility of the concentration systems to deposit the analyte on an area of less than 0.01 mm(2). This article proposes a fundamentally new approach to the analyte enrichment, based on the effect of non-uniform electrostatic field on the evaporating droplet. This approach, combined with the optimized geometry of a superhydrophobic/superhydrophilic concentration system allows more than a six-fold reduction of the deposition area. Potentially, this makes it possible to improve the detection limit of the plasmonic sensors by the same factor, bringing it down to the attomolar level.

Automated summary

Recently, sensors using surface-enhanced Raman scattering (SERS) detectors combined with superhydrophobic/superhydrophilic analyte concentration systems have shown the ability to reach detection limits below the femto-molar level. However, the sensitivity of these sensors is limited by the concentration systems' inability to deposit the analyte on an area smaller than 0.01 mm². This article proposes a new approach to analyte enrichment by utilizing the effect of non-uniform electrostatic field on evaporating droplets, which, when combined with an optimized superhydrophobic/superhydrophilic concentration system, can reduce the deposition area by more than six times. This has the potential to improve the detection limit of plasmonic sensors to the attomolar level.