'Because you don't need refrigeration and it can be self-administered, you could post the vaccine out to people,' Prof. Mark Kendall says of the nano-patch. (University of Queensland)

Australian researchers have developed a needle-free, dissolving vaccination that they say could be mailed to households during a pandemic.

Unlike other next-generation vaccinations, the Australian development uses micro-projections made from dried vaccine.

The nano-patch is outlined in the latest edition of the journal Small.

Prof. Mark Kendall, of the University of Queensland's Australian Institute for Biotechnology and Nanotechnology, said this new form of vaccination doesn't require refrigeration and eliminates any chance of needle-stick injuries.

"The World Health Organization estimates that 30 per cent of vaccinations in Africa are unsafe due to cross-contamination caused by needle-stick injury," Kendall said.

Kendall said the nano-patch is smaller than a postage stamp and has 20,000 projections per square centimetre.

These projections are made from the dried vaccine bonded with an excipient or inert substance, such as carboxymethylcellulose.

When the patch is placed against the skin, the projections push through the outer skin layer and deliver the biomolecules to the target cells.

"Currently most vaccines are delivered with the needle and syringe into muscle, which has few immune cells," he said.

"In contrast, the skin is abundant in immune cells, offering great potential for vaccines, if we can successfully exploit it with practical delivery devices."

Kendall said the device is stable and strong when dry. But when the nano-patch is applied to the skin, the projections immediately become wet, and dissolve within minutes.

The work follows from an April paper by the team in the journal PLos One that showed the nano-patch triggered a protective immune response using one-100th of the standard needle and syringe dose.

Kendall said this is 10 times better than any other delivery method.

Counters 'needle phobia'

The latest paper comes in the wake of work by Prof. Mark Prausnitz of Georgia Institute of Technology on dissolving microneedles, published in last week's Nature Medicine.

But Kendall said Prausnitz's approach still uses needles for delivery and does not show any real improvement in vaccine immune response over the traditional needle and syringe approach.

He said the nano-patch would also be of benefit to the 10 per cent of the population with needle phobia.

Kendall added that because it uses one-100th of the dose the cost to the health system is reduced.

He said in a pandemic situation the reduced dose would also make it easier for governments to supply enough vaccinations.

"Because you don't need refrigeration and it can be self-administered, you could post the vaccine out to people," Kendall said.

The next step is to establish clinical trials.