NanomedicineCenter.com

Nanoparticles aren’t toxic at small sizes

Scientists from the Pacific Northwest National Laboratory in Chicago have performed a research whose outcome gave the opportunity to experts to conclude that the finest nanoparticles, which are widely used in nanomedicine and bioengineering, aren’t really toxic. This should definitely calm some scientists who claimed that human tissues might react inadequate if exposed to small nanoparticles.

Researchers from Chicago, led by Brian Thrall, discovered that size doesn’t matter. “If you consider surface area as the dose metric, then you get similar types of responses independent of the size of the particle,” said Thrall. “That suggests the chemistry that drives the biological responses doesn’t change when you get down to the smallest nanoparticle.”

In general, it’s very hard to measure toxicity — some measure it by total weight, some by the number of particles. “Different dose metrics give different impressions of which particles are more toxic,” said Thrall. “We measured the dose at which the particles caused a biological response. That was either death of the cell, or a change in which genes the cell turned on and off. In the end, we found out that the biological response was very similar regardless of the size of the nanoparticles.”

The research was funded by the National Institutes of Health.

Source: pnl.gov/aaas/

Gold nanospheres kill cancer

A group of researchers from the UC Santa Cruz, led by Li Chun, have developed a nanosphere which is able to kill cancer, thus significantly improving tumor treatment and moving it another step forward.

Scientists have found that tiny shells made of pure gold can cling to cancer cells and “cook” them when heated. This method is still in development phase, and far from human use. However, tests on animals were very successful, and that’s promising.
The nanospheres are 50 nanometers in diameter. They were actually developed by Jin Zhang. When he developed them, he didn’t expect the spheres to have medical value. But after seeing Chun speak about using nanoparticles to treat cancer at a conference, he changed his mind.
“This is the ideal structure for this purpose,” Zhang said.

To make these spheres into structures which can kill cancer, scientists attached a short chain of molecules designed to bind to tumor cells. Then, they injected the nanospheres into cancerous mice. The molecule on the spheres snapped into receptors on the tumor cells like a key in a lock. The researchers then shone infrared light on the tumor, heating the gold and frying the cancer cells. Because the hollow nanospheres absorb infrared light so efficiently, the targeted treatment helps keep healthy tissue safe, the scientists said.

The group of scientists said that they plan to do more research on this matter, because it’s necessary in order to expand the use of this to humans.

Source: santacruzsentinel.com/localnews/ci_11656076

How is an antibiotic effective against bacteria

Researchers from United Kingdom and Australia have created a way of using nanotechnology (nanomedicine) standards to get to know how an antibiotic is effective against bacteria.

Many bacteria (golden staph, for example) are getting resistant to antibiotics, thus becoming an issue for the complete health image of the community.
“It order to attack this problem we need to understand not only the ways in which bacteria develop and exhibit resistance to antibiotics, but also how new antibiotics can work to kill or slow the growth of resistant bacteria,” said Professor Matt Cooper from Australia.

The research was done by creating nano-probes coated with molecules found in bacterial cell walls from normal bacteria and bacteria resistant to antibiotics. Then they added doses of the “last resort” antibiotic, vancomycin, to the system and found that probes from normal bacteria were stressed and changed shape, whereas probes from resistant bacteria were only weakly affected. This way scientists quickly realized the effectiveness of an antibiotic.

“This advance will help us to understand the mode of action of drugs targeted against resistant bacteria, and could also lead to rapid diagnostic tools and novel methods of investigating antibiotic action,” said Cooper. “There is only a tiny molecular difference between resistant and non-resistant bacteria. We now know that these probes can detect that difference, and can do so within minutes.”

The details can be found in the journal Nature Nanotechnology.

Source: uq.edu.au