The University of Florida is seeking companies interested in commercializing nanotubes composed of lignin, a major component of plant cell walls. Nanotechnology-enabled drug delivery systems (DDS) for cancer treatment are one of the most promising medical applications of nanotechnology to date. Specifically, scientists have experimented with filling carbon nanotubes with cancer-fighting medications. These anti-cancer drugs are often also toxic to healthy tissue resulting in side effects such as hair loss, digestive upset, lethargy and ulcers. The protective carbon shell afforded by carbon nanotubes provides some protection to healthy tissue. Unfortunately, research has revealed that carbon nanotubes, with their thin, needle-like shape, behave much like asbestos fibers when introduced into the living tissue. Their large surface-area-to-volume ratio, in particular, makes them highly reactive, increasing the risk of free-radical production and inflammation. These DDS not only damage proteins, membranes and DNA, but might even promote cancer formation, the very condition it’s hoped they can be used to treat. Researchers at the University of Florida have created softer, more flexible lignin nanotubes that are expected to greatly reduce the negative health effects associated with carbon nanotube-enabled DDS. An additional advantage over traditional carbon nanotubes based on the buckminsterfullerene structure is that lignin nanotubes are easier to functionalize and are naturally fluorescent. Lignin, a plant cell-wall polymer, is generated as a waste product from paper mills and biorefineries, a cheap and abundant source of the raw starting material. This invention, which could eliminate the problem of nanotoxicology, has enormous marketplace potential. The nano-enabled DDS market is projected to reach $220 billion by 2015. If nanotoxicology were no longer a concern, this figure could climb even higher.
A drug-delivery system that can deliver medications to specific sites within the body (e.g. tumors) without damaging healthy tissue
- Anticipated to have superior biocompatibility and biodegradability, making it safer than traditional carbon nanotubes for health-related applications
- Composed of inexpensive raw materials, resulting in lower manufacturing costs
- Structure’s length, wall thickness and optical properties can be easily modified, maximizing utility
- Functionalized more easily than existing alternatives, enhancing versatility for a multitude of nanotechnology uses
Nearly 40 years ago, the term nanotechnology was coined to describe the miniaturization of manmade devices. Decades later, carbon nanotubes were celebrated as universal delivery systems that could bring about a new era in cancer treatment. Their size could be altered so that they would be small enough to pass though the relatively leaky blood vessel walls found in malignant tissue, but too large to pass though the smaller holes found in healthy tissue, a process called passive targeting. When peptides or antibodies that bind specifically with cancer cells were added, scientists could even actively target tumors. The risks associated with traditional carbon nanotubes, however, were not immediately recognized. The downside of this technology is that the carbon nanotube’s chemical inertness and sharp edges seem to increase the prevalence of dangerous free radicals. University of Florida researchers have developed nanotubes that are softer, more flexible, and derived from a naturally occurring plant polymer, making them safer for health-related applications. They synthesized these lignin-based structures in a template of commercially available alumina membranes and added layers of dehydrogenation polymer onto a lignin base layer via a peroxidase-catalyzed reaction to modify structural and optical properties.