Invisibly small stands tall

LOS ANGELES—Researchers from UCLA and Northwestern University are using nanotechnology to develop a new way to deliver drugs that is invisible to the immune system. With nanoscale polymer films—about four nanometers per layer—the research team built a platform of sorts to hold and slowly release an anti-inflammatory drug, a significant drug delivery hurdle that could lead to new and better therapeutic delivery methods for cancer and other diseases.

 
The study provides an example of the enormous potential and clinical significance that nanomaterials may represent in such fields as oncology, endocrinology and cardiology.

"One of the key advantages with the nanocloak polymer/nanofilm devices that we are developing is that it is a platform system that can be integrated with virtually any drug (chemically synthesized, protein/antibody-based, etc.)," says Dean Ho, an assistant professor of biomedical and mechanical engineering with the McCormick School of Engineering and Applied Science, a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University and the study's senior author.

The researchers used nanoscale polymer films, about four nanometers per layer, to build a sort of matrix or platform to hold and slowly release an anti-inflammatory drug. The films are orders of magnitude thinner than conventional drug delivery coatings, says Genhong Cheng, a researcher at UCLA's Jonsson Comprehensive Cancer Center and one of the study's authors.

"Using this system, drugs could be released slowly and under control for weeks or longer," says Cheng, a professor of microbiology and molecular genetics.

Researchers coated tiny chips with layers of the nanoscale polymer films, which are inert and helped provide a Harry Potter-like invisibility cloak for the chips, hiding them from the body's natural defenses. They then added Dexamethasone, an anti-inflammatory drug, between the layers. The chips were implanted in mice, and researchers found that the Dexamethasone-coated films suppressed the expression of cytokines, proteins released by the cells of the immune system to initiate a response to a foreign invader. Mice without implants and those with uncoated implants were studied to compare immune response.

The uncoated implants generated an inflammatory response from the surrounding tissue, which ultimately would have led to the body's rejection of the implant and the breakdown of its functionality. However, tissue from the mice without implants and the mice with the nano-cloaked implants were virtually identical, proving that the film-coated implants were effectively shielded from the body's defense system, says Edward Chow, a former UCLA graduate student who participated in the study and is one of its authors.

"The next step of the project will involve using the nanocloaking polymer as the foundation for an implantable nanofilm device for localized cancer treatment," says Ho, adding that within the next year or so, the technology could see rapid movement towards its next phase of development.

The technology also may prove to be an effective approach for delivering multiple drugs, controlling the sequence of multi-drug delivery.