In the lymph node, specific lymphocytes targeted at the antigen in the vaccine are produced - these cells persist in the body as memory cells
Then if an actual infection occurs, the memory cells are primed and ready to act and combat the infection e.g. produce antibodies specific to the antigen.
Animation Watch the Vaccination and Transdermal Patch Animations to improve your understanding of delivering vaccines and drugs via the skin.
Benefits Of Transdermal Patches Image: Courtesy Nanotechnology Victoria Ltd What are the benefits of transdermal delivery from a medical point of view?
Benefits Of Transdermal Patches Image: Courtesy Nanotechnology Victoria Ltd
Protrusions can be specifically engineered to ensure:
Delivery directly to immune cells therefore less material required
Painless application and no scar tissue formation
Versatility in applications: vaccines, drugs, hormones, wound healing proteins.
Microscopic images of transdermal patch protrusions
Benefits Of Transdermal Patches
Transdermal patches can deliver nano-formulated drugs/vaccines, which - have unique properties - can easily enter blood vessels once delivered to skin - can target particular cell types, such as immune cells
Examples of drugs that could be patch-delivered: - proteins such as insulin
Examples of vaccines that could be patch delivered: - protein vaccines - DNA vaccines.
Benefits Of Transdermal Patches
Due to directed delivery of nano-formulated drugs/vaccines, the use of patches means that - only small quantities of drugs/vaccines are required - less drug/vaccine is ‘wasted’ i.e. dispersed in blood or connective tissue before it reaches target cells - less side effects due to small dosage delivered directly to target cells - an optimal immune response is generated.
Nano-Formulated Vaccines Trigger An Optimal Immune Response Image: Courtesy Nanotechnology Victoria Ltd, based on data from Intersuisse Bioscience, 2006 Data was generated by vaccinating mice with various sized particles, and then counting the number of activated immune cells. Vaccine particle size Immune response (number of activated immune cells per million total cells) 0 30nm 100nm 500nm 1000nm
Advantages Of Transdermal Patches: Summary Image: pruzicka@flcikr
Delivery of nano-sized particles directly to the immune system
Delivery of molecules that normally cannot penetrate the skin
Lower dosages = less side effects
Easy to use, no needle-stick injury, low risk of infection, pain-free
Can be self-administered, or given by a non-medical person
Smaller, lighter, lower transport cost
Mass production = cost benefits
Suitable for public health programs e.g. air-drop into disaster zones
Suitable for veterinary purposes
Biocompatible and biodegradable material used to make patches
Can achieve short- & long-term delivery.
Other Examples Of Transdermal Patches Image: andreas@flickr
In addition to Nanotechnology Victoria, other groups within Australia are working on transdermal patches eg Dr Mark Kendall at AIBN, Queensland - developing a micro-nano projection array patch (‘Nanopatch’) - could be used for vaccination or DNA delivery - vaccine/DNA molecules are ‘dry-coated’ on to the patch projections for delivery to target cells through the top layer of skin (epidermis)
Nicotine patches (to help smokers quit) - plastic chamber within patch contains nicotine - a selectively permeable membrane allows diffusion of nicotine into the skin.