Research

Elucidating nanomaterial interactions with plant/algae biosurfaces and biomolecules for developping targeted and controlled release tools

The mechanisms of uptake, transport, and distribution of nanoparticles in plants and algae are poorly understood. Our research has highlighted that the surface properties of nanoparticles determine their transport through plant/algae membranes. We are discovering how nanomaterial properties such as size, surface chemistry, and aspect ratios, biomolecule coatings shape their interaction with plant/algae lipid membranes, cell walls, proteins, lipids and other biomolecules. We aim to leverage this knowledge to enable novel targeted and controlled chemical and biomolecule delivery tools for plants/algae and advance agriculture, biofuels, and biomanufacturing technologies. We have developed carbon based nanocarriers that target the delivery of chemical and DNA cargoes to chloroplasts and the plant vasculature mediated by biorecognition of peptides and sucrose molecules. These nanocarriers can signficantly enhance the delivery efficiency of agrochemicals, pesticide active ingredients, and nucleic acids in plants.

Nanosensor approaches for understanding plant signaling and enabling plant communication with electronic devices

Signaling molecules play a central role in controlling metabolism, stress resistance, growth and development in plants. We are developing nanosensors to image and quantify with precision the location and concentration of signaling molecules in plants. Our research has shown that carbon nanotube-based sensors enable the detection of nitric oxide and hydrogen peroxide in extracted chloroplasts and leaves of living plants. We have used this approach to develop plants that report their health or stress levels in real time to electronic devices. Optical nanomaterials offer a robust platform for detection of plant signaling molecules in vivo. They do not photobleach and can take down the detection limit to the single-molecule level. Our objective is to develop nanoparticle-based sensors for monitoring subcellular spatial and temporal changes in plant signaling molecules in real-time. This will allow us to understand  the role of  signaling molecules in the regulation of plant physiological mechanisms. Our nanosensors approach is leading to plants that act as environmental and crop health monitoring devices.

Nanotechnology as a tool to study and engineer plant/algae tolerance to stress

Environmental stress leads to accumulation of reactive oxygen species (ROS) and consequent decrease in photosynthetic performance. We are demonstrating that interfacing negatively charged spherical cerium oxide nanoparticles (nanoceria) with chloroplasts in vivo augments ROS scavenging and photosynthesis of Arabidopsis thaliana plants under excess light, heat, and dark chilling. Nanoceria are transported into chloroplasts via non-endocytic pathways, influenced by the electrochemical gradient of the plasma membrane potential. Nanoceria augment plant ROS scavenging including superoxide anion and hydroxyl radicals, for the latter ROS there is no known plant enzyme scavenger. Plants with embedded nanoceria that are exposed to abiotic stress have enhanced quantum yield of photosystem II, carbon assimilation rates, and Rubisco carboxylation rates relative to plants without nanoparticles.

Engineering and understanding chloroplast function with nanomaterials

We are demonstrating that that engineered nanomaterials enhance chloroplast photosynthesis, act as gene delivery tools, and turn chloroplasts into biomanufacturing devices. For example, semiconducting single walled carbon nanotubes (SWNT) enhance photosynthesis by capturing solar energy in wavelengths that are weakly absorbed by chloroplasts. Cerium oxide nanoparticles (nanoceria) act as potent antioxidants protecting plant photosynthesis from reactive oxygen species accumulation (ROS). We are also utilizing carbon nanostructures to deliver chemical cargoes and plasmid DNA and augment chloroplast function in plants and algae. This nanoengineering approach may lead to crops with improved stress tolerance and plants/algae that act as biomanufacturing platforms on demand.