Custom made nanoparticles will transform cancer diagnosis and treatment

Mar 28 2006

Researchers have developed "custom" nanoparticles that promise to provide a more targeted and effective way of delivering anticancer drugs than conventional medications or any of the earlier attempts to fight cancer with nanoparticles.

The special nanoparticles were designed at the molecular level to attack specific types of cancer without affecting healthy cells.

The researchers from the University of North Carolina (UNC) at Chapel Hill, say the nanoparticles also have the potential to reduce the nasty side effects associated with chemotherapy.

According to researchers, the particles, which are considered to be the next generation of cancer therapeutics, are the most uniform, shape-specific drug delivery particles developed to date.

They say other potential benefits of the tiny uniform particles include enhanced imaging of cancer cells for improved diagnosis and use as delivery vehicles for gene therapy agents.

To date, the UNC researchers have produced a variety of custom nanoparticles from biocompatible organic materials using techniques they adapted from processes used by the electronics industry to make transistors.

In cell studies, they have shown that the uniform nanoparticles can attach to specific cell targets, release important chemotherapy drugs inside cells, and hold MRI contrast agents.

The researchers say animal studies began recently and human studies are anticipated.

Study leader Joseph DeSimone, Ph.D., a chemistry professor at UNC and director of the school’s Institute for Advanced Materials, Nanoscience and Technology, has co-founded a company, Liquidia Technologies, to develop and produce the nanoparticles and believes they will transform the way disease is detected and treated.

DeSimone says researchers have been experimenting with nanoparticles as drug delivery vehicles for years but have had only limited success in cell and animal studies.

Each carrier has drawbacks with regard to stability in the bloodstream or ability to be directed toward a specific cancer site.

He says there has also been no general method available that allows precise control of the particle’s size, shape and composition, which are considered key features for the success of targeted drug delivery.

DeSimone and his associates at UNC have developed a new fabrication technique that allows, for the first time, unprecedented control over the structure and function of drug delivery nanoparticles.

Called PRINT (Particle Replication In Non-wetting Templates), the technique is apparently similar to injection molding and uses principles borrowed from the electronics industry for transistor fabrication.

The manufacturing process starts with a silicon wafer that is etched with the shape and size of the desired nanoparticle, resulting in a template, then nonstick liquid fluoropolymers are poured into the template and cured to form a fixed mold.

DeSimone says the finished mold is then injected with organic materials that can contain imaging agents, anticancer drugs, DNA (for gene therapy) and other materials, depending on the intended function.

The new manufacturing technique apparently uses gentler processing methods that are less likely to harm important organic components than traditional nanoparticle manufacturing techniques.

The resulting nanoparticles can be as small as 20 nanometers, or thousands of times smaller than the width of a single human hair.

The shapes of the particles can also be made to mimic the shapes of objects found in nature like red blood cells or virus particles, DeSimone says.

The technique was first detailed last June in the online version of the Journal of the American Chemical Society.

The study was presented at the 231st national meeting of the American Chemical Society, the world’s largest scientific society.