Delivery of biomolecules to plants via carbon nanofiber arrays Joanna Jelenska1, Sandra M. Davern2, Jessica Morgan1,3, Timothy E. McKnight2, Robert F. Standaert4, Jennifer L. Morrell-Falvey2,5, Saed Mirzadeh2, Jean T. Greenberg1 1Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL; 2Oak Ridge National Laboratory, Oak Ridge, TN; 3Biophysical Sciences, The University of Chicago, Chicago, IL; 4East Tennessee State University, Johnson City, TN; 5University of Tennessee, Knoxville, TN We used vertically aligned carbon nanofiber (VACNF) arrays as a new tool for microdelivery of biomolecules to plant leaves and other organs. We demonstrated that nanofibers penetrate the leaf surface and deliver sub microliter quantities of labeled molecules into Populus epidermal and palisade cells without disrupting cell or tissue integrity or inducing wound response. We showed that these arrays can deliver various macromolecules such as dyes (fluorescein, Lucifer yellow, propidium iodide), dextran and proteins into Populus and Arabidopsis leaves. Our studies tracked movement of the cucurbit phloem-mobile protein CmPP16-1 and GFP within a single leaf and throughout the plant. After VACNF-induced microdelivery into Populus leaf, both proteins moved bidirectionally, indicating phloem loading. Recently, we were able to successfully deliver DNA and transiently transform cells to express several probes and markers in multiple crop plant species in different organs – these studies are presented in a separate poster by a PhD student Jessica Morgan. We plan to use nanofiber arrays to deliver CRISPR/Cas proteins or transcripts and guide RNA to crop plants (lettuce) to edit the genome while avoiding stable introduction of editing materials and subsequent undesired off-target events. The ultimate goal will be allele replacement in sensitive cultivars to obtain lettuce resistant to pathogens without introduction of foreign genetic material.