1 research outputs found
Food Quality Monitor: Paper-Based Plasmonic Sensors Prepared Through Reversal Nanoimprinting for Rapid Detection of Biogenic Amine Odorants
This paper describes
the fabrication of paper-based plasmonic refractometric sensors through
the embedding of metal nanoparticles (NPs) onto flexible papers using
reversal nanoimprint lithography. The NP-embedded papers can serve
as gas sensors for the detection of volatile biogenic amines (BAs)
released from spoiled food. Commercial inkjet papers were employed
as sensor substratesî—¸their high reflectance (>80%) and smooth
surfaces (roughness: ca. 4.9 nm) providing significant optical signals
for reflection-mode plasmonic refractometric sensing and high particle
transfer efficiency, respectively; in addition, because inkjet papers
have lightweight and are burnable and flexible, they are especially
suitable for developing portable, disposable, cost-effective, eco-friendly
sensing platforms. Solid silver NPs (SNPs), solid gold NPs (GNPs),
and hollow Au–Ag alloyed NPs (HGNs) were immobilized on a solid
mold and then transferred directly onto the softened paper surfaces.
The particle number density and exposure height of the embedded NPs
were dependent on two imprinting parameters: applied pressure and
temperature. The optimal samples exhibited high particle transfer
efficiency (ca. 85%), a sufficient exposure surface area (ca. 50%
of particle surface area) presented to the target molecules, and a
strong resonance reflectance dip for detection. Moreover, the HGN-embedded
paper displayed a significant wavelength dip shift upon the spontaneous
adsorption of BA vapors (e.g., Δλ = 33 nm for putrescine;
Δλ = 24 nm for spermidine), indicating high refractometric
sensitivity; in contrast, no visible spectroscopic responses were
observed with respect to other possibly coexisting gases (e.g., air,
N<sub>2</sub>, CO<sub>2</sub>, water vapor) during the food storage
process, indicating high selectivity. Finally, the plasmonic sensing
papers were used to monitor the freshness of a food product (salmon)