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.”