Fiber‐optic SERS sensor with optimized geometry: testing and optimization

Abstract

A unique, geometry-optimized, surface-enhanced Raman scattering (SERS) fiber-optic sensor has been recently developed and built. Though this class of sensors can be very useful in many applications, their use is greatly hindered by the fact that their\ud reusability can hardly be achieved because of the irreversible adsorption of the analyte molecules on the SERS-active substrate.\ud Different substrates have been tested on our sensor with the purpose of increasing its reusability by means of cleaning\ud procedures or good reproducibility in manufacturing the sensor, keeping, however, the same enhancement. We show that a\ud partial reusability of the sensor is possible using SERS-active substrates prepared by a standard process of immobilization of\ud silver nanoparticleswith 3-aminopropyltrimethoxysilane.We also show that a fairly good reproducibility can be achieved with\ud a low-cost substrate realized in a short time by depositing a layer of polyvinyl alcohol (PVA) containing silver nanoparticles on\ud the etched fiber tip.We prove as well that measurements are possible evenwith nanoparticles dispersed in the analyte solution\ud instead of using a substrate directlymade on the sensor tip. Finally, we have successfully tested our sensorwith somemolecules\ud cited in EFSA (European Food Safety Authority) and FDA (Food and Drug Administration) reports as molecules for which new\ud detectionmethods are necessary

Fiber optic probes for linear and nonlinear Raman applications – Current trends and future development

“…The signal obtained from SERS probes can further be increased by shaping the fiber tip (Viets and Hill ; Lucotti and Zerbi ), e.g., angled (Viets and Hill ) or conically (Lucotti and Zerbi , Pesapane et al ). Viets and Hill observed the largest additional enhancement for silver films on 40° angled fiber tips .…”

Recent advances in linear and nonlinear Raman spectroscopy. Part V

“…Adenine and guanine, nucleobases present in both DNA and RNA strands, and microRNA containing adenine and guanine have been used as testing ligands for identifying traces of nucleic acids in Martian rocks and sediments. A unique, geometry‐optimized, SERS fiber‐optic sensor was recently developed and built by Pesapane, Lucotti and Zerbi . Good reproducibility was achieved with a low‐cost substrate realized in a short time by depositing a layer of polyvinyl alcohol containing silver NPs on the etched fiber tip.…”

Produção de substratos sers eficientes através da deposição de ouro sobre um molde de microesferas de poliestireno

“…O desvio padrão médio das intensidades SERS da 4-pyS medido nestes substratos vidro-Au foi da ordem de 20%, que é comparável à reprodutibilidade obtida para alguns substratos apresentados na literatura. 14,23,24 A flutuação nas profundidades e diâmetros das estruturas de Au, observada nas Figuras 3S e 4S (material suplementar), respectivamente, também contribui para uma diminuição na reprodutibilidade do sinal SERS. Esta heterogeneidade leva a uma distribuição de condições de ressonância plasmônica, de tal forma que se tem uma distribuição de intensificações ao longo de toda a superfície, o que leva aos desvios observados de intensidade absoluta das bandas SERS da 4-pyS.…”