Nanopatch Immunization Uses 1/100 Amount of Vaccine

A new study has found that a vaccine delivered by a nanopatch induces a similarly protective immune response as a vaccine delivered by needle and syringe, but uses 100 times less vaccine.

Researchers at the University of Queensland (UQ; Australia) designed a nanopatch composed of densely packed micro-nanoprojections--over 20,000 "spikes” per cm²--to deposit antigen to large numbers of epidermal Langerhans cells and dermal dendritic cells directly. The researchers then controllably applied the nanopatches to mice with discrete conditions between peak tissue-strain rates of approximately 100 s^-1 to 7,000 s^-1, and quantified the resulting penetration depths, delivery payloads, and skin mechanics. By increasing the strain rate of the application, the researchers were able to overcome key skin variability, achieving increases in both projection penetration depth of over 50% (by length) and area coverage of a full array by 50% to 100%.

According to the researchers, this delivery depth precision opens the way for utilizing the skin's immune function more fully. Furthermore, the researchers uncovered new insights on the mechanical behavior of skin tissue, including internal skin property changes that could affect and facilitate penetration, the puncture mechanics of skin in this strain rate range, and aspects of the nanoprojection design criteria that could be used to dictate penetration depth. The study was published ahead of print on March 11, 2010, in Biomaterials.

"The Nanopatch targeted specific antigen-presenting cells are found in a narrow layer just beneath the skin surface, and as a result we used less than one hundredth of the dose used by a needle while stimulating a comparable immune response,” said lead author Prof. Mark Kendall, Ph.D., of the Australian Institute for Bioengineering and Nanotechnology at the UQ. "Our result is ten times better than the best results achieved by other delivery methods and does not require the use of other immune stimulants, called adjuvants, or multiple vaccinations.”

"Because the Nanopatch requires neither a trained practitioner to administer it nor refrigeration, it has enormous potential to cheaply deliver vaccines in developing nations,” added Professor Kendall. "When compared to a needle and syringe, a nanopatch is cheap to produce, and it is easy to imagine a situation in which a government might provide vaccinations for a pandemic such as swine flu to be collected from a chemist or sent in the mail.”

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University of Queensland