Mapping gold nanoparticles on and in edible leaves in situ using surface enhanced Raman spectroscopy

Abstract

The increased prevalence of engineered nanomaterials (ENPs) in the environment and their potential toxicity require study on whether those engineered nanomaterials could possibly contaminate agricultural food and products. However, many techniques require invasive and complicated sample preparation procedures to detect and characterize engineered nanomaterials in complex matrices. Here, we present a non-destructive and label-free approach based on surface enhanced Raman spectroscopic (SERS) mapping technique to qualitatively detect and characterize gold nanoparticles (Au NPs), on and in spinach leaves in situ. We were able to detect the clearly enhanced signals from Au NPs at 15 to 125 nm on and in spinach leaves. Peak characterizations revealed the aggregation status of Au NPs and their interactions with plant biomolecules, such as chlorophylls and carotenoids. This developed approach will open a new analytical platform for various researches on studying ENPs' adhesion and accumulation.

Multiple Method Analysis of TiO2 Nanoparticle Uptake in Rice (Oryza sativa L.) Plants

“…Though a growing number of studies are emerging on NP interactions with terrestrial plants, available analytical techniques and associated sample pretreatment methods are limited for assessing the NPs within biological tissues. Some of the most frequently used detection techniques for NPs in plant tissues are electron microscopy (EM), X-ray absorption spectroscopy (XAS), surface enhanced Raman scattering (SERS), and total elemental analysis methods. − An early study used 2.8 nm Alizarin red S-bound (ARS) TiO 2 NPs to test the uptake potential in Arabidopsis seedlings . However, the surface sites of these TiO 2 NPs were saturated with sucrose before ARS-labeling, which may have modified the NP uptake potential.…”

Investigation of the Impact of a Pesticide Adjuvant on Dimethoate Persistence, Penetration, and Stability on Apples Using Surface-Enhanced Raman Spectroscopy

“…SERS technique allows the in situ detection of dimethoate on apples without the need for pesticide extraction using AuNPs as the substrate. AuNPs were used as SERS substrates in this study due to their low cytotoxicity and good biocompatibility. − Our previous studies demonstrated that the AuNP mirror substrate was able to improve the sensitivity and reproducibility of the detection due to its more uniform distribution than AuNPs. Thus, the AuNP mirror was applied as a SERS substrate in this study.…”

Plant extract reduced and stabilized gold Nanoparticles as model particles for foliar application of fertilizers

“…It was shown that NPs are capable of crossing plant mechanical barriers (e.g. cuticle and cell walls) with further translocation [6][7][8]. Moreover, NPs surfaces are easily modifiable with a variety of coatings and, similar to drug delivery, NP surface properties can theoretically be tuned to deliver them to specific leaf structures or tissues in plants [9,10].…”

“…The leaf itself is covered with a layer of hydrophobic epicuticular waxes [11,12]. In general, there are three main natural pathways how NPs could penetrate cuticle layerstomates, trichomes and pores [6,7,9].…”