The emergence of nanomaterials in consumer products has increased concern for their potential hazards in the environment and biological systems. Therefore, the monitoring of nanoparticles in biological systems is of great importance. Despite the numerous attempts, the methods to evaluate the uptake, translocation, and accumulation of nanomaterials inside the plant tissue are still limited. In this study, for the first time, we proposed the monitoring of the silver nanoparticles (AgNPs) in different tissues of the plant through surface-enhanced Raman spectroscopy (SERS) approach. For this, chemically (Che-AgNPs) and green-synthesized AgNPs (Gr-AgNPs) were prepared properly and their surfaces were functionalized with Raman-active molecule. With the contribution of electromagnetic enhancement, our NP systems provided high signal-to-noise SERS spectra. After exposure to NPs to maize seedlings as a model plant, we detected that AgNPs were accumulated mainly in the epidermis and cortex of the root and phloem parts of the shoot. Highly distinctive SERS spectra were collected from the root and shoot cross-section of each NP system. Also, the accumulation of the AgNPs was furtherly confirmed through inductively-coupled mass spectrometry and scanning electron microscopy analysis. Moreover, the exposure of AgNPs to maize seedlings led to remarkable alterations in both phytotoxic and biomolecular indicators including chlorophyll, protein and, antioxidant enzymes.
Keywords: Maize seedlings; Nanoparticle monitoring; Phytotoxicity; Silver nanoparticles; Surface-enhanced Raman spectroscopy (SERS).
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