Nanomaterials used to localize, control drug delivery

Using nanotechnology, scientists from UCLA and Northwestern University have developed a localized and controlled drug delivery method that is invisible to the immune system, a discovery that could provide newer and more effective treatments for cancer and other diseases.

The study, published last month in the journal ACS Nano, 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 (e.g. 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," said Cheng, a professor of microbiology, immunology and molecular genetics. "A drug that is given orally or through the bloodstream travels throughout the system and dissipates from the body much more quickly. Using a more localized and controlled approach could limit side effects, particularly with chemotherapy drugs."

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.

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 nanomaterial technology serves as a non-invasive and biocompatible platform for the delivery of a broad range of therapeutics, adds Ho.

The study was funded by the Center for Cell Control and Northwestern University, with additional support from the Jonsson Cancer Center, National Institute of Allergy and Infectious Disease of the National Institutes of Health and the V Foundation for Cancer Research. The Center for Cell Control is one of the Nanomedicine Development Centers funded by the National Institutes of Health through the Roadmap for Medical Research.