CAMBRIDGE, Mass. — On a global scale, over one million people die each year due to ailments that could have been prevented if they were properly vaccinated. A large portion of those deaths are in developing nations, and health officials say one of the biggest obstacles facing vaccination campaigns in these areas is a lack of adequate medical infrastructure and record keeping. Due to these deficiencies, it’s especially difficult for local doctors to determine which individuals are in need of a particular vaccine.
With this problem in mind, researchers from MIT have developed a rather unexpected solution: patients’ vaccination history data can be stored inside a pattern of dye that is invisible to the naked eye, and then injected into their skin at the same time they receive a vaccination. This way, the next time that individual visits a hospital, doctor’s office, etc., their vaccination history will be readily available to medical professionals who otherwise would be in the dark about that person’s medical history in that regard.
“In areas where paper vaccination cards are often lost or do not exist at all, and electronic databases are unheard of, this technology could enable the rapid and anonymous detection of patient vaccination history to ensure that every child is vaccinated,” says Kevin McHugh, a former MIT postdoc and current assistant professor of bioengineering at Rice University, in a statement.
This newly developed dye, consisting of nanocrystals called quantum dots, can remain safely under human skin for at least five years. While under patients’ skin, the dye emits a near-infrared light that, while completely invisible to human eyes, can be picked up by a specially-equipped smartphone.
MIT researchers recognized years ago that there was a pressing need for some type of vaccine information storage system that didn’t require a centralized database or some other type of formal, physical infrastructure in developing nations. For example, many vaccines, such as those designed to prevent measles or mumps, require multiple doses over a certain period of time. So, without accurate records of prior doses for doctors to work with, it’s become very common for children in certain areas not to get all of their required vaccinations.
“In order to be protected against most pathogens, one needs multiple vaccinations,” comments Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research. “In some areas in the developing world, it can be very challenging to do this, as there is a lack of data about who has been vaccinated and whether they need additional shots or not.”
The quantum dots developed by researchers are copper-based, and only about 4 nanometers in diameter. Additionally, each dot is surrounded by biocompatible micro-particles that form a protective sphere of about 20 microns. These spheres ensure the dots stay in place under patients’ skin after the initial injection.
You may be imagining the dye being delivered using a traditional syringe, that that’s not the case; the dye was designed to be injected via a micro-needle patch. These patches are already being widely used to deliver vaccines all over the world, and the research team have already proven that their dye is easily compatible with the patches.
When a patch is applied to a patient’s skin, the 1.5 millimeter long micro-needles within the patch partially dissolve into the skin, fully releasing the dye within about two minutes. The patches can be customized to store different imprints, or data, depending on the type of vaccine being delivered and the specific patient’s needs.
“It’s possible someday that this ‘invisible’ approach could create new possibilities for data storage, biosensing, and vaccine applications that could improve how medical care is provided, particularly in the developing world,” comments Robert Langer, the David H. Koch Institute Professor at MIT.
The research team used human cadavers to confirm that the dye could be detected by smartphone cameras up to five years after injection, and also used rat testing to make sure the dye did not interfere with the effectiveness of the vaccine being delivered.
“This study confirmed that incorporating the vaccine with the dye in the micro-needle patches did not affect the efficacy of the vaccine or our ability to detect the dye,” Ana Jaklenec explains.
As far as next steps, the team at MIT plan on consulting with health professionals in developing African nations on the most efficient way to start introducing the dye. Furthermore, they are working on expanding the amount of data that can be included within the dye, such as dates of prior vaccinations.
Finally, while the research team are confident that the dye, and more particularly the quantum dots, are safe, they nonetheless plan to conduct further safety studies before trying the dye out on actual human patients.
The study is published in the scientific journal Science Translational Medicine.