Bombarding our Food Supply with Nanotechnology Magnetic Transfection

Magnetofection

One emerging tool in the biotech toolkit is the use of magnetic iron-oxide nanoparticles bonded with DNA. This method is challenging to adapt to plant engineering. Scientists can overcome barriers using fluorescently-labeled and bar-coded magnetic nanoparticles as carriers to deliver genes through these cell-wall-free apertures.  Magnetic fields are then applied to provide directional forces to transport the nanoparticle gene carriers into pollens. Using several types of imaging devices, scientists can track the florescence and energy until they make it to their final destination. Using the same polymerase chain reaction (PCR) test you are required to use - that results in a Darwinian Directed Evolution mutagenesis - they were able to successfully integrate transgenic characteristics to the genome, including successful inheritance to offspring.  Magnetofection works in many plant species including pumpkin, lily, and cotton.

Pollen is an attractive biological target to transfect because pollen grains carry the male gametes, and so could generate a complete genetically modified plant after fertilization in the plant ovules. Scientists are really excited about magnetofection because it allows for them to avoid using time-consuming tissue culture based on regenerable tissues. Regeneration is feasible but technically very challenging for both sorghum and maize, monocot species. However, magnetofection is likely not a simple, universal pollen transfection method.

Carbon Nanotube Transfection

Research is demonstrating that aside from the use of magnetic nanoparticles, carbon nanotubes are also an increasingly popular nano-tool for plant transfection.  Carbon nanotubes rely on passive delivery as a plant transformation tool. Research teams physically adsorb and electrostatically graft DNA encoding using green fluorescent protein (GFP) onto single-walled carbon nanotubes and showed that their technique can effectively deliver DNA into the leaves of a variety of plant species including wheat, cotton, and arugula for transient gene expressions. Carbon nanotube technology did not result in significant toxicity in mature leaves by performing quantitative PCR analysis of NbrbohB, a known stress gene.

A new species is engineered when isolates from arugula leaves were able to internalize carbon nanotubes and stably expressed the GFP plasmid with 80% inheritable transfer.

siRNA (si=small interfering RNA) is a useful material for transient plant genetic engineering. Using single-walled carbon nanotubes demonstrated that transfection of siRNA to inhibit and silence expressions of GFP in the leaves of tobacco plant occurred for up to a week. siRNA is biocompatible for use in plants.

The impact of using nanoparticles for plant genetic engineering is that delivery of DNA and RNA can be accomplished without pathogens ballistic force that disrupts the plant tissue. siRNA is considered to be a green alternative to the use of chemical pesticides, or the delivery of mRNA for DNA-free genetic manipulation of plants.

Problems Exist

Nanotechnology has significantly enhanced genetic engineering and reprogramming of humans, animals, and plants.  The first problem is that while it is relatively easy to engineer human and animals, plant cells have rigid cell walls which exclude large particles.  It is unknown whether nanoparticles are able to diffuse easily through the multi-layered cell wall and then into the cell membrane.  Complex biological differences among plant species and the types of biological materials from plants (leaves, pollens, and regenerable tissues like root hairs) mean that systematic characterization of plant-nanoparticle interactions are needed to enhance transfection outcomes.

Another problem relates to the size of the DNA cargo that can be delivered into plant cells, which is directly correlated to the surface area of the nanoparticles. Thus far, only small spherical nanoparticles and single-walled cylindrical carbon nanotubes have shown utility to transfect plant cells through passive diffusion and/or with the use of mechanical aid such as a gene gun. Unfortunately, this means that only small gene cargo load with potential for plant damage.

It has been shown that nanoparticles like carbon nanotubes can adversely inhibiting the growth of tomato and lettuce with some cell toxcitity after nanoparticle transfection.

Finally, most of the nanotechnology techniques for plant transfection offers transient gene expression. Long-term reproducible "phenotypes" [mutations] are necessary for bringing transfected crops to the commercial market. 

Plant genetic engineering will become increasingly important because of growing population and increased demand for food, medicine, and materials.  High-tech collaborators aim to energize the plant transformation toolkit using nanotechnology to generate positive societal impact.

Conclusion

We all must be ever vigilant in our food purchases. With some foods you will be able to visibly see technology at work, but most will remain invisible to the naked eye. The safest thing we can all do is grow our own food.  We should also be diligent about blessing our food and asking the Lord to cover it and to protect us from unwittingly eating corrupted foods. 

May you be blessed with pure food and nutrition,

Celeste