Nanodiamonds 100 times cheaper, used to track cells in the body and deliver chemotherapy drugs

Taiwanese scientists have found a way to slash the cost of making the diamond chips by around 100 times.

Nanodiamond's fluorescent properties could be used to track cells moving through the body. And, last year, researchers showed they could safely deliver chemotherapy drugs.

Cheaper alternatives to nanodiamonds, such as fluorescent dyes or small chunks of semiconductor known as quantum dots, are in use already. The diamonds, though, are less prone to blinking on and off than fluorescent dyes, and are not toxic to cells, unlike quantum dots.

FNDs are usually made by firing a high-energy electron beam into commercially available diamond powder and heating it up to 800 °C. Huan-Cheng Chang and colleagues at Academia Sinica in Taipei shoot a much less intense, and hence cheaper, beam of helium ions at diamond powder to make FNDs of the same quality.

Chang's team could track the movement of a single fluorescent nanodiamond within a cell for over 3 minutes.

The researchers have also explored other applications for their cheap diamonds, such as using them to monitor stem cells in developing tissue, or to carry drugs into cells.

"In particular, we have demonstrated that FNDs are able to interact with plasmid DNA and to deliver different genes into cultured human cells," Chang told New Scientist. That could be used for gene therapy, or DNA vaccines.

Chang and his colleagues have set up a commercial operation selling their nanodiamonds and are working on making them even smaller and to fluoresce more brightly.

The cheaper diamond chips need to be made smaller, though, if they are to perform well as markers to reveal the inner workings of cells, he adds.

Nanoemulsion vaccines

A novel technique for vaccinating against a variety of infectious diseases – using an oil-based emulsion placed in the nose, rather than needles – has proved able to produce a strong immune response against smallpox and HIV in two new studies.

The results build on previous success in animal studies with a nasal nanoemulsion vaccine for influenza, reported by University of Michigan researchers in 2003.

Nanoemulsion vaccines developed at the Michigan Nanotechnology Institute for Medicine and the Biological Sciences at U-M are based on a mixture of soybean oil, alcohol, water and detergents emulsified into ultra-small particles smaller than 400 nanometers wide, or 1/200th the width of a human hair. These are combined with part or all of the disease-causing microbe to trigger the body’s immune response.

The surface tension of the nanoparticles disrupts membranes and destroys microbes but does not harm most human cells due to their location within body tissues. Nanoemulsion vaccines are highly effective at penetrating the mucous membranes in the nose and initiating strong and protective types of immune response, Baker says. U-M researchers are also exploring nasal nanoemulsion vaccines to protect against bioterrorism agents and hepatitis B.

The smallpox results, which appear in the February issue of Clinical Vaccine Immunology, could lead to an effective human vaccine against smallpox that is safer than the present live-vaccinia virus vaccine because it would use nanoemulsion-killed vaccinia virus, says Baker.

Anna U. Bielinska, Ph.D., a research assistant professor in internal medicine at the U-M Medical School, and others on Baker’s research team developed a killed-vaccinia virus nanoemulsion vaccine which they placed in the noses of mice to trigger an immune response. They found the vaccine produced both mucosal and antibody immunity, as well as Th1 cellular immunity, an important measure of protective immunity.

When the mice were exposed to live vaccinia virus to test the vaccine’s protective effect, all of them survived, while none of the unvaccinated control mice did. The researchers conclude that the nanoemulsion vaccinia vaccine offers protection equal to that of the existing vaccine, without the risk of using a live virus or the need for an inflammatory adjuvant such as alum hydroxide.

In antibody immunity, antibodies bind invading microbes as they circulate through the body. In cellular immunity, the immune system attacks invaders inside infected cells. There is growing interest in vaccines that induce mucosal immunity, in which the immune system stops and kills the invader in mucous membranes before it enters body systems.

A National Institutes of Health program, the Great Lakes Regional Centers of Excellence for Biodefense and Emerging Infectious Diseases, funded the research. If the federal government conducts further studies and finds the nanoemulsion smallpox vaccine effective in people, it could be a safer way to protect citizens and health care workers in the event of a bioterrorism attack involving smallpox, Baker says.

That would allay concerns about the current vaccine’s safety which arose in 2002. On the eve of the Iraq War, the Bush administration proposed a voluntary program to vaccinate military personnel and 500,000 health care workers with the existing vaccine to prepare for the possible use of smallpox virus as a biological weapon.

Nanoparticle Vaccine Is Both More Effective And Less Expensive

from Sciencedaily, bioengineering researchers from the EPFL in Lausanne, Switzerland, have developed and patented a nanoparticle that can deliver vaccines more effectively, with fewer side effects, and at a fraction of the cost of current vaccine technologies.

This technology may make it possible to vaccinate against diseases like hepatitis and malaria with a single injection. And at an estimated cost of only a dollar a dose, this technology represents a real breakthrough for vaccine efforts in the developing world.

Thanks to recent advances, an immune response can be triggered with just a single protein from a virus or bacterium. Recent research has also shown that the best way to get sustained immunity is to deliver an antigen directly to specialized immune cells known as dendritic cells (DCs). Current methods have trouble obtaining an adequate immune response with a single injection and can cause side effects or even be toxic.

EPFL professors Jeff Hubbell and Melody Swartz and PhD student Sai Reddy have engineered nanoparticles that completely overcome these limitations. At a mere 25 nanometers, these particles are so tiny that once injected, they flow through the skin's extracellular matrix, making a beeline to the lymph nodes. Within minutes, they've reached a concentration of DCs thousands of times greater than in the skin. The immune response can then be extremely strong and effective.

In addition, the EPFL team has also engineered a special chemical coating for the nanoparticles that mimics the surface chemistry of a bacterial cell wall. The DCs don't recognize this as a specific invader, but do know that it's something foreign, and so a low-level, generic immune reaction known as "complement" is triggered. This results in a particularly potent immune response without the risk of unpleasant or toxic side effects.

Cost and logistics are important factors, especially for use in developing countries. Unlike other nanoparticle vaccine technologies that degrade in water and thus require expensive drying and handling procedures, the EPFL team's nanoparticles won't degrade until they are in the body. They are in liquid form and don't require refrigeration, so preparation and handling costs are reduced, and they are easy to transport.

More study is required to achieve these goals," she adds, "but we have every reason to believe this technique could be in use within five years."