Materials Project
Micro-needle Vaccines:
According to World Health Organization statistics, more than 3 million people die every year in developing countries due to a lack of access to vaccinations. It is difficult to transport and store vaccines as they must be stored at temperatures between 2 and 8 degrees Celsius to keep them active and effective; Access to refrigeration is often very difficult to attain in developing countries. Additionally, risks of transmitting blood borne diseases through hypodermic needles can be very high if needles are not sterilized or disposed of properly. As an attempt to solve these problems, King's College in London has been working to create a new form of vaccine involving the use of micro-needles in the form of a 'vaccine patch.'
Dr Linda Klavinskis from the Peter Gorer Department of Immunobiology at King’s College London said, “We have shown that it is possible to maintain the effectiveness of a live vaccine by drying it in sugar and applying it to the skin using micro-needles – a potentially painless alternative to hypodermic needles. We have also uncovered the role of specific cells in the skin which act as a surveillance system, picking up the vaccine by this delivery system and kick-starting the body’s immune processes.” Scientists at King's College observed that not only does the patch immunize test subjects to the disease injected, but there have been observed cases where the 'vaccine patch' worked more efficiently in vaccinating the test subjects, than vaccines we use today with hypodermic needles.
This innovation may eventually become a replacement for hypodermic needle vaccines according to scientists at King's College researching the vaccine patch. This form of vaccination is painless and does not cause bleeding, this may make vaccinations look more attractive to those afraid of needles, and help to vaccinate a greater majority against harmful diseases. The vaccine is made of a live, dehydrated virus which can be held at most temperatures without losing effectiveness. This will make sending vaccinations to developing countries where refrigeration is not available easier, making it possible to immunize a greater number of people.
Micro-needle vaccines use tiny biodegradable needles which are absorbed into the skin leaving no trace of sharp points or blood. This will ensure safety of all recipients of the vaccine, as dirty needles will not be shared, spreading blood borne diseases. Scientists from Georgia Institute of Technology say the 'vaccine patch' can be, “fabricated using low-cost manufacturing methods” the patches will be very cost efficient; sending them to developing countries would cost very little. These are only a few of the benefits to this form of vaccination, it is a safe, efficient way of vaccinating and eventually could be used worldwide.
Throughout history, many methods were created to vaccinate people against diseases such as small pox or measles. Early on, vaccination included scratching away a section of skin, and then applying the diseased cells of another person to the exposed area. This exposed people to the disease through the skin, helping to create an immunization for the body to the specific disease. The 'vaccine patch' works in a similar way to what was done in the past using a virus from a disease and applying it to the skin.
Before the virus (in the form of a vaccine patch) is injected into the body, it must first be dehydrated, this keeps the virus in a stable state where it can be stored outside of the low temperatures required for hypodermic needle vaccinations. A substance called Trehalose, a form of sugar, is added to the host cells of a virus to dehydrate them. Trehalose is different from other methods of dehydration as it turns the host cells of a virus to a gelatine state, preventing disruption of organelles within the cell. Once the cells are in this state, it is possible to restore their activity through re-hydrating them with water. When the cells are re-hydrated after this process, they will begin to work just as they did before dehydration, when if the cells had undergone a different form of dehydration, it would not be possible to return them to their original working state.
Once the cells are dehydrated, the virus is mixed with a liquified version of sucrose, or a non-toxic, biodegradable polymer, to hold the shape of the micro-needles, and is then poured into micro-needle array molds. This will become the 'vaccine patch,' it is in the shape of a very small square with a tiny array of very sharp needles protruding from one side. The vaccine is released into the body when the patch is pressed into the skin. The micro-needles will cut through the skin, allowing the micro-needles to come into contact with bodily fluids. The sucrose micro-needles will dissolve into these fluids within minutes, leaving only the backing of the patch. At this time the virus will come in contact with water inside the body, and will be re-hydrated, resuming the activity of the cells, working to immunize the body to the virus.