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.