Tiny silicon needles can deliver drugs with less pain in each prick, according to U.S researchers.

Dr Devin McAllister of the Georgia Institute of Technology and his team in Atlanta created a variety of needle shapes using different materials.

They published their findings in this week's issue of the Proceedings of the National Academy of Sciences.

The microneedles were made of silicon, metal and biodegradable polymer. They were then tested on how well they could pierce human skin and deliver insulin to diabetic rats.

The researchers said that in addition to hollow needles used for intravenous injections, arrays of up to 400 solid needles can be used to increase the skin’s permeability, making it easier to carry drugs directly across the skin.

Australian researcher Professor Frank Caruso from the University of Melbourne said using solid needles to increase the permeability of skin was very interesting.

"The microneedles pierce the skin so they can increase permeability by orders of magnitude. This may be able to provide the delivery of macromolecules across the skin. That's quite important."

Caruso said that microneedles could also be used to inject nanospheres. These nanospheres could release drugs slowly, over a period of time, or in a sudden burst.

At one to 1000 micrometres in size, the needles sit somewhere between conventional needles that can be painful for patients, and nanotubes, another technology developed to delivery drugs.

"Microneedles sit at the interface between transdermal patches and hypodermic needles, attempting to gain the advantages and eliminate the disadvantages of each," said the researchers.

Dr Minoo Moghaddam from Australia’s CSIRO Molecular Science said microneedles would be probably much less painful than regular needles, especially for delivering drugs like kids' vaccines.

However Moghaddam said that there are many advantages in using nanotubes over the microneedle technology.

"Nanotubes might be more painless and are very strong and stable, much more stable than stainless steel but very flexible."

Moghaddam said that microneedles are made by etching a surface and then depositing various materials on that to make a microneedle.

"Nanotubes on the other hand are being built from the bottom up, on the molecular level," she said.

Back