Gold Nanoparticle Detection with Laser-Induced Photoacoustic Signal in Arabidopsis

Gold nanoparticles (GNPs) are one of most widespread nanoparticles in use for biomedical applications, such as immunoassays, clinical, phototherapy of cancer cells, targeted delivery of drugs and optical bioimaging. Use of nanoparticles in plants has not yet been fully investigated however, only few methods are available for visualizing and quantifying nanoparticles to assess uptake, translocation and stability in planta. Recently, we found that GNPs can be easily detected quantitatively in leaves by laser-induced photoacoustic imaging and leaf temperature can be elevated by GNP mediated photothermal effect. Here, we detect 60 nm GNP with photoacoustic signal and find that (i) 60 nm GNP reached to the leaf tip from leaf petiole inside 4 hours, (ii) GNPs are finally localized in leaf vein, hydathode of leaf marginal part. This work demonstrates that nanoparticles can be rapidly taken up through the leaf vein and expected to be eliminated through leaf phloem or hydathode.