Vaccination with a dissolving microneedle array

(Nanowerk News) The effectiveness of a vaccine strongly depends on the ability of the vaccine components to reach and activate antigenpresenting cells, especially dendritic cells in the lymphoid organs. Vaccines do not reach lymphoid APCs are ignored by the immune system, leading to unresponsiveness. On the other hand, vaccines are not confined to immune system access the systemic circulation and exert adverse effects systemically.
Researchers from Wayne State University now have demonstrated the utility of dissolving microneedle arrays designs for the lymph node delivery of amphiphilic vaccines released upon skin insertion (i.e. subcutaneous injection).
Microneedle administration of vaccines via the skin provides a cost-effective, easy, and safe approach without the need for trained personnel. It could even lead to self-administration of vaccines.
Dissolving Microneedle Arrays for Transdermal Delivery of Amphiphilic Vaccines
Mechanisms of direct access to draining lymph nodes through “albumin hitchhiking approach” upon a rapid dispersion of amphiphilic vaccines (amph-vaccines) released by a simple application of dissolving microneedles (MNs). After 5 min application of dissolving MNs into a dermis layer of the skin which is highly perfused with lymphatic capillary networks, released amph-vaccines from dissolving MNs bind and complex to endogenous albumin, and efficiently drain into draining lymph nodes, lead to enhanced lymphatic delivery. (© Wiley-VCH Verlag) (click on image to enlarge)
As the team writes in their report in Small ("Dissolving Microneedle Arrays for Transdermal Delivery of Amphiphilic Vaccines"), this approach can provide a number of safety and immunological advantages compared to hypodermic needles.
First, dissolving microneedle arrays generate no biohazardous sharp wastes because the microneedle arrays dissolve and disappear upon insertion. The pedestal part of microneedle arrays is also made of the water-soluble polymer so that it can easily be eliminated by dissolving in water.
This safety feature removes the risk of accidental needle-stick injury or intentional reuse of needles, which is common in some developing countries and is responsible for close to one million deaths per year due to transmission of hepatitis B, human immunodeficient virus (HIV), and other infectious diseases.
Second, the microneedle arrays delivery enhances the immune response through inflammatory cues and targeted delivery of antigen and adjuvant to the high density of antigen-presenting cells in lymph nodes.
This approach can greatly increase the safety profile of administered vaccines by effectively guiding them to draining lymph nodes, reducing systemic dissemination.
"Lymph node targeting vaccines delivered by microneedle arrays may provide not only practical advantages compared to hypodermic needles but also better humoral and cellular immunity," the authors conclude their report. "This strategy can be used as an effective platform for straightforward and robust transcutaneous self-administrative vaccines."
Michael Berger By – Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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