As any parent who’s held down a screaming toddler in a pediatrician’s office can attest, childhood immunizations — while necessary — can be difficult. With up to five pokes required at a single visit, multiple boosters for a single vaccine, and a flu shot recommended each year, it can be difficult for even the most organized caregiver to keep up.
Luckily, researchers at Massachusetts Institute of Technology have just invented a new method that could allow all immunizations to be condensed into a single jab. The procedure was outlined in a September paper published in Science.
SEAL, which stands for StampEd Assembly of polymer Layers, is a 3-D fabrication technique that allows for a new kind of drug-delivery particle. The particles, which resemble minuscule coffee cups, are generated from an FDA-approved polymer and can be filled with a vaccine before being sealed with a tiny “lid.” The particles can then be designed to degrade, thus releasing their contents, at varying times.
"We are very excited about this work,” MIT’s Robert Langer said in a release. “For the first time, we can create a library of tiny, encased vaccine particles, each programmed to release at a precise, predictable time, so that people could potentially receive a single injection that, in effect, would have multiple boosters already built into it. This could have a significant impact on patients everywhere."
SEAL was created as part of a project funded by the Bill and Melinda Gates Foundation, with the goal of increasing vaccine compliance in developing nations.
“In the developing world, it might be the difference between not getting vaccinated and receiving all of your vaccines in one shot,” said MIT’s Kevin McHugh.
The particles are created in silicon molds that were designed with photolithography, a kind of printing that uses light to transfer patterns. The team then uses a custom dispenser to fill the “cups” before heat-sealing them with their polymer “lids.”
“Each layer is first fabricated on its own, and then they’re assembled together,” said Ana Jaklenec, one of the authors of the study, in a release. “Part of the novelty is really in how we align and seal the layers. In doing so we developed a new method that can make structures which current 3-D printing methods cannot.”
Though no human clinical trials are planned for the near future, the researchers say the technique has proven successful in mice: After a single injection, particles were released at nine, 20 and 41 days. At both nine and 41 days, the mice showed a strong immune response to the particles’ contained substances, showing that the method is indeed viable.
The researchers have also designed particles that can degrade hundreds of days after injection, but the challenge remains to ensure the medication or vaccine can remain stable at body temperature for that long. The team is also testing the viability of using the particles to deliver other substances, such as medications.
Said Langer: “The SEAL technique could provide a new platform that can create nearly any tiny, fillable object with nearly any material, which could provide unprecedented opportunities in manufacturing in medicine and other areas.”