Researchers have created nanotubes from plant material that are much more flexible than rigid carbon nanotubes currently used.
The lignin nanotubes—about 500 times smaller than a human eyelash—can deliver DNA directly into the nucleus of human cells in tissue culture, where this DNA could then correct genetic conditions. Experiments with DNA injection are currently being conducted with carbon nanotubes, as well.
“That was a surprising result,” says Wilfred Vermerris, associate professor of microbiology and cell science at the University of Florida. “If you can do this in actual human beings you could fix defective genes that cause disease symptoms and replace them with functional DNA delivered with these nanotubes.”
The nanotube is made up of lignin from plant material obtained from biofuel pilot facility. Lignin is an integral part of the secondary cell walls of plants and enables water movement from the roots to the leaves, but it is not used to make biofuels and would otherwise be burned to generate heat or electricity at the biofuel plant.
The lignin nanotubes can be made from a variety of plant residues, including sorghum, poplar, loblolly pine, and sugar cane.
For the study, published in the journal Biomacromolecules, researchers first tested to see if the nanotubes were toxic to human cells and were surprised to find that they were less so than carbon nanotubes—which means they can deliver a higher dose of medicine to the human cell tissue.
Next they needed to know if the nanotubes could deliver plasmid DNA to the same cells. It turns out that they can. A plasmid is a small DNA molecule that is physically separate from, and can replicate independently of, chromosomal DNA within a cell.
Genetic disorders and cancer
“It’s not a very smooth road because we had to try different experiments to confirm the results,” says Elena Ten, a postdoctoral research associate. “But it was very fruitful.”
In cases of genetic disorders, the nanotube would be loaded with a functioning copy of a gene, and injected into the body, where it would target the affected tissue, which then makes the missing protein and corrects the genetic disorder.
Although Vermerris cautions that treatment in humans is many years away, among the conditions that these gene-carrying nanotubes could correct include cystic fibrosis and muscular dystrophy. But, patients would have to take the corrective DNA via nanotubes on a continuing basis.
Another approach under consideration is to use the lignin nanotubes for the delivery of chemotherapy drugs in cancer patients. The nanotubes would ensure the drugs only get to the tumor without affecting healthy tissues.
The US Department of Agriculture, the Public Health Service, the National Institutes of Health, the Children’s Miracle Network, Alex’s Lemonade Stand Foundation for Childhood Cancer, and Bankhead-Colely Cancer Research Program supported the work.
Source: University of Florida