Medical Device Daily Washington Editor

When old meets new, ideas are sometimes hard to convey, but members of the 130-year old American Chemical Society (ACS; Washington) recently heard a wide range of presentations on the world of nanotechnology, with many discussions covering a range of medical uses for these space-age harbingers of hope.

This year's national meeting of the ACS, held in San Francisco, ran from Sept. 10-12 and included a discussion of how nanotubes can help adult stem cells take the shape and size of brain cells.

Thomas Webster of Brown University (Providence, Rhode Island) and several colleagues at Yonsei University (Seoul, South Korea) described an effort to mix healthy rat stem cells with carbon nanotubes and implant them into the brains of three rats that had suffered strokes. The controls got either nanotubes or stem cells, but not both.

An eight-week follow-up showed that the stem cells migrated to distant parts of the brain when injected without nanotubes and that neither these nor the other three controls displayed any improvement in neurological function.

However, stem cells in the trio receiving the mixture of cells and nanotubes made the morphological leap into functioning neurons. Webster said that the findings could have important implications for the treatment of a number of neurological disorders, including Alzheimer's and Parkinson's diseases.

A similar idea was applied to mice with heart attacks by another team.

Samuel Stupp, Ph.D., chemist and director of the Institute of Bionanotechnology in Medicine at Northwestern University (Evanston, Illinois) used nanoparticles derived from polysaccharides and peptide amphiphiles amplified the signals that pass between cells that trigger blood vessel formation. After one month, the hearts of the treated mice were functioning almost as well as those of healthy mice. Controls, which received no treatment, could muster up only about 50% of normal heart function.

Stupp said that medical science may find a role for nanoparticles in treatment of diabetes: a search of the National Library of Medicine web site (PubMed) shows that this idea has been under discussion in the medical community at least since 2005.

Not to be left out, researchers at Johns Hopkins Institute for NanoBioTechnology (Baltimore) have bridged another chasm in the effort to use small chips of various materials to control the release of drugs in the human body.

The Hopkins team used gold electrodes about the diameter of a human hair manufactured by photolithography, the process computer chipmakers use in their clean rooms. “We used a gold electrode because gold is a good conductor of electricity,” said grad student Prasheed Mali, “and because it's an inert metal, it wouldn't get involved in any of the chemical reactions.”

Peter Searson, a professor of materials science and engineering at Hopkins who directed the research, drew an analogy between the chip and “a balloon tethered to a surface.” “We use an electrical impulse to cut the tether and it floats away,” he said.

The chemical agent is attached to the surface of the chip by means of a long-chain hydrocarbon molecule and a gold-sulfur bond. The small electrical jolt separated the sulfur atom from the gold platform, releasing the chemical agent to do its work.

Searson said that the technique “is relatively simple, but nothing like this has been done before.”

Most of the existing work done in this realm has focused on “preventing this from happening,” he said.

If this approach pans out, drug makers could use biocompatible implant chips to release medicine inside a patient on demand.

CDC: Diabetes projections increase

While drug and device makers strive to come up with ever-better treatments for diabetes, the need for a permanent cure becomes ever more pressing if the most recent figures from the Centers for Disease Control and Prevention (CDC; Atlanta) are credible.

A recent article in the diabetes journal Diabetes Care upgrades earlier estimates and found that a convergence of increasing incidence and decreasing mortality promises to balloon the numbers of Americans living with the disease far beyond projections made only five years ago.

K.M. Venkat Narayan, MD, an epidemiologist at CDC, said that “if incidence rates continue to rise, the impact on future numbers with diabetes and consequent healthcare costs will be much more devastating.”

And that devastation appears to be indicated by a look at the CDC's previous and current projections.

In 2001, an article in Diabetes Care, based on CDC studies, said that the rate of diagnosis “is projected to increase 165%, from 11 million in 2000 . . . to 29 million in 2050,” an increase in prevalence from 4% to 7.2%. Two years later, the CDC numbers indicated that the numbers would increase to 39 million by 2050, but declining mortality and increasing diagnosis have left even those numbers in shreds.

Now, the most recent estimate from CDC is that 16.2 million cases of diabetes were present in the U.S. in 2005, and the prevalence is now expected to jump from 5.62% last year to 12% over the next 44 years.

The Baby Boomer generation has much of the burden for the expected increase, partly due to its numerical prominence, but parents of Boomers are also likely to cluck over the lifestyle choices of their offspring.

The CDC expects Boomers between 65 and 74 will triple the current rate of diabetes for that age slot, and that those older than 75 will be diagnosed five times more frequently than the current cohort.

Other demographic trends indicate a distinctly varied racial burden: diabetes among whites is expected to double by 2050, whereas the rates for African-Americans may triple in that time. Latino populations are expected to exhibit a six-fold increase in incidence.