Effective localized collection and identification of airborne species through electrodynamic precipitation and SERS-based detection

Abstract

Various nanostructured sensor designs currently aim to achieve or claim single molecular detection by a reduction of the active sensor size. However, a reduction of the sensor size has the negative effect of reducing the capture probability considering the diffusion-based analyte transport commonly used. Here we introduce and apply a localized programmable electrodynamic precipitation concept as an alternative to diffusion. The process provides higher collection rates of airborne species and detection at lower concentration. As an example, we compare an identical nanostructured surfaced-enhanced Raman spectroscopy sensor with and without localized delivery and find that the sensitivity and detection time is improved by at least two orders of magnitudes. Localized collection in an active-matrix array-like fashion is also tested, yielding hybrid molecular arrays on a single chip over a broad range of molecular weights, including small benzenethiol (110.18 Da) and 4-fluorobenzenethiol (128.17 Da), or large macromolecules such as anti-mouse IgG (~150 kDa).

Ultrasensitive surface-enhanced Raman scattering detection in common fluids

“…Despite the significance of detecting explosives, poisonous airborne compounds, chemical warfare agents, and environmental pollutants dispersed in air, gas-phase SERS detection remains extremely challenging. Detection of these species generally needs specially designed molecule collection systems [e.g., electrodynamic precipitation (17)] and is limited to specific airborne species (52). We used our SLIPSERS for sensitive detection of airborne species without any periphery molecule collection equipment (Fig.…”

“…Among various analytical techniques, surface-enhanced Raman scattering (SERS) is among the most promising methods in detecting trace amounts of molecules owing to its high molecular specificity (i.e., differentiation between different types of molecules) and high sensitivity (i.e., the lowest analyte concentration from which SERS signals are distinguishable from the noise signal of a control sample) (9)(10)(11)(12)(13)(14)(15)(16)(17). Extensive studies have focused on the structural optimization of the SERS substrate to improve SERS sensitivity (18)(19)(20)(21)(22), but there are two important roadblocks that limit its practical applications.…”

SERS-Based Sensitive Detection of Organophosphorus Nerve Agents

“…The detection based on surface-enhanced Raman scattering (SERS) effect, which has been extensively reported since its discovery in the 1970s [6][7][8][9][10][11][12][13][14], would be an appropriate and effective method for fast and ultrasensitive detection. The SERS effect originates from a significant enhancement in the effective Raman cross-section of the target molecules situated at or very near to the roughened noble metal surfaces or colloidal particles [15][16][17][18][19][20][21][22][23][24][25].…”

Vapor phase SERS sensor based on mesoporous silica decorated with silver nanoparticles

“…At the same time, ordinary materials for SERS with ecological, pharmaceutical, biological and medical applications are commonly designed for the analysis of liquid analytes [1][2][3][4][5][6][7][8][9][10] while a limited number of actual research efforts has focused on vapor phase detection [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. The latter challenge evidently widens the promising application area of SERS and therefore requires novel approaches for the design of SERS-active materials.…”

“…Accordingly, the sensitivity of the analysis becomes even higher if porous silver nanocubes [12], polymer coatings [15], anisotropic nanoparticle aggregates [16,24], metal -organic frameworks [21,26], multihole capillaries [23], graphene oxide surface [28], free -surface microfluidic chips [18], electrodynamic precipitation [17] are applied.…”