Carbon nanofiber arrays deliver fluorescent OG-CmPP16-1 into a Populus leaf.

(a) Epifluorescence micrograph of the impaled region. The outline of the VACNF chip (ca. 2 × 2 mm) is indicated by the large dashed box. (b) Close-up view of a leaf vein junction showing carbon nanofiber spikes resident in the leaf. Arrows indicate clusters of fibers, in which individual fibers are visible as small black dots. (c) Composite epifluorescence image showing bidirectional movement of the labeled protein from the site of impalement with the VACNF array. The images were recorded 5–10 min after introduction of OG-CmPP16-1. Results shown are representative of 5 separate experiments (one plant per experiment). (d) Accumulation of fluorescence at the hydathodes was observed in 2 of 5 experiments 30 min after VACNF delivery. The black square indicates the location of the VACNF chip.