I’ve talked before about how lotions work, and skin absorption rates, and the claims of certain cosmetics manufacturers that they have a product which will “penetrate the skin” and do magical mystical (usually anti-aging) things. But we know, unless a product has been deliberately designed to penetrate multiple skin layers, the skin doesn’t let much get through, which is why doctors use needles.

But a team of nanotech researchers at Queensland University (Australia) reports to have created a patch smaller than a postage stamp, that can replace vaccines and other needle based delivery methods. The delivery of vaccine is accomplished by millions of microprojections (like tiny needles but at the microscale – about the width of a hair).

The nanoprojections puncture the top layer of skin to reach specific cells in the epidermis called Langerhans cells. These are the first skin members of the body’s immune system. They pick up the antigen from the nanopatch and move it to the lymph nodes, the hubs of the immune system. Once in the lymph nodes, the Langerhans cells mature and make the antigen available to another worker in the immune system, the T-cell.

T-cells are studded with receptors – tiny protuberances designed to pick up the molecular configuration of antigens in this case presented by Langerhans cells. The T-cells come in many different types, and among the types are sometimes differentiated to be sensitive to only one type of antigen. When it comes in contact with that antigen, it binds it to a receptor and from then on ‘remembers’ that type of antigen. The T-cells work together with B-cells to provide an attack on specific antigens whenever they are detected in the body. This is the basis of immunization.

The nanopatch approach is designed to directly affect T-cell immunization with a huge advantage in being able to ‘educate’ the T-cells about a particular antigen without the need for actually suffering the disease. Its effect, in some cases, is stronger than needle injected vaccine especially for infections such as HIV and malaria. The nanopatch is generally inexpensive to manufacture and typically requires much less vaccine.

It should be noted that the nanopatch is still undergoing trials in mice.

Crichton, M., Ansaldo, A., Chen, X., Prow, T., Fernando, G., & Kendall, M. (2010). The effect of strain rate on the precision of penetration of short densely-packed microprojection array patches coated with vaccine Biomaterials, 31 (16), 4562-4572 DOI: 10.1016/j.biomaterials.2010.02.022